Weak acids reacted with weak bases can produce ionic compounds with both the conjugate base ion and conjugate acid ion, such as ammonium acetate. Some ions are classed as amphoteric, being able to react with either an acid or a base. This is also true of some compounds with ionic character, typically oxides or hydroxides of less-electropositive metals (so the compound also has significant covalent character), such as zinc oxide, aluminium hydroxide, aluminium oxide and lead(II) oxide.
Acidity/basicity
Ionic compound
Ionic compound | Acidity/basicity
Ammonium acetate, zinc oxide, aluminum hydroxide,  aluminium oxide and lead(II) oxide. Sodium chloride and ammonium carbonate Ions Sodium chloride (NaCl),  Hydroxide (OH), ammonium carbonate, etc.
describe in general terms the structure of ionic solids such as nacl
user
Ions typically pack into extremely regular crystalline structures, in an arrangement that minimizes the lattice energy.
assistant
what can you tell me about their boiling point?
user
Boiling points exhibit similar trends to melting points in terms of the size of ions and strength of other interactions. When vapourized, the ions are still not freed of one another.
assistant
can you name any compounds?
user
Boiling points exhibit similar trends to melting points in terms of the size of ions and strength of other interactions. When vapourized, the ions are still not freed of one another. For example, in the vapour phase sodium chloride exists as diatomic "molecules".
Ionic compound | Melting and boiling points
Some substances with larger ions, however, have a melting point below or near room temperature (often defined as up to 100 °C), and are termed ionic liquids. Ions in ionic liquids often have uneven charge distributions, or bulky substituents like hydrocarbon chains, which also play a role in determining the strength of the interactions and propensity to melt. Even when the local structure and bonding of an ionic solid is disrupted sufficiently to melt it, there are still strong long-range electrostatic forces of attraction holding the liquid together and preventing ions boiling to form a gas phase. This means that even room temperature ionic liquids have low vapour pressures, and require substantially higher temperatures to boil.
Ionic compound | Melting and boiling points
Electrostatic forces between particles are strongest when the charges are high, and the distance between the nuclei of the ions is small. In such cases, the compounds generally have very high melting and boiling points and a low vapour pressure. Trends in melting points can be even better explained when the structure and ionic size ratio is taken into account. Above their melting point ionic solids melt and become molten salts (although some ionic compounds such as aluminium chloride and iron(III) chloride show molecule-like structures in the liquid phase). Inorganic compounds with simple ions typically have small ions, and thus have high melting points, so are solids at room temperature.
Ionic compound | Melting and boiling points
If there are multiple different cations and/or anions, multiplicative prefixes ("di-", "tri-", "tetra-", ...) are often required to indicate the relative compositions, and cations then anions are listed in alphabetical order. For example, KMgCl is named magnesium potassium trichloride to distinguish it from KMgCl, magnesium dipotassium tetrachloride (note that in both the empirical formula and the written name, the cations appear in alphabetical order, but the order varies between them because the symbol for potassium is K). When one of the ions already has a multiplicative prefix within its name, the alternate multiplicative prefixes ("bis-", "tris-", "tetrakis-", ...) are used.
Ionic compound | Nomenclature
According to the nomenclature recommended by IUPAC, ionic compounds are named according to their composition, not their structure. In the most simple case of a binary ionic compound with no possible ambiguity about the charges and thus the stoichiometry, the common name is written using two words. The name of the cation (the unmodified element name for monatomic cations) comes first, followed by the name of the anion. For example, MgCl is named magnesium chloride, and NaSO is named sodium sulfate (, sulfate, is an example of a polyatomic ion). To obtain the empirical formula from these names, the stoichiometry can be deduced from the charges on the ions, and the requirement of overall charge neutrality.
Ionic compound | Nomenclature
Arrhenius acids are named according to their anions. In the classical naming system, the ionic suffix is dropped and replaced with a new suffix, according to the table following. The prefix "hydro-" is used when the acid is made up of just hydrogen and one other element. For example, HCl has chloride as its anion, so the hydro- prefix is used, and the -ide suffix makes the name take the form hydrochloric acid. "Classical naming system:" In the IUPAC naming system, "aqueous" is simply added to the name of the ionic compound. Thus, for hydrogen chloride, as an acid solution, the IUPAC name is aqueous hydrogen chloride.
Acid | Nomenclature
For example, the uranyl(2+) ion, , has uranium in an oxidation state of +6, so would be called a dioxouranium(VI) ion in Stock nomenclature. An even older naming system for metal cations, also still widely used, appended the suffixes "-ous" and "-ic" to the Latin root of the name, to give special names for the low and high oxidation states. For example, this scheme uses "ferrous" and "ferric", for iron(II) and iron(III) respectively, so the examples given above were classically named ferrous sulfate and ferric sulfate.
Ionic compound | Nomenclature
For example, Ba(BrF) is named barium bis(tetrafluoridobromate). Compounds containing one or more elements which can exist in a variety of charge/oxidation states will have a stoichiometry that depends on which oxidation states are present, to ensure overall neutrality. This can be indicated in the name by specifying either the oxidation state of the elements present, or the charge on the ions. Because of the risk of ambiguity in allocating oxidation states, IUPAC prefers direct indication of the ionic charge numbers. These are written as an arabic integer followed by the sign (... , 2−, 1−, 1+, 2+, ...) in parentheses directly after the name of the cation (without a space separating them).
Ionic compound | Nomenclature
An ionic compound is named by its cation followed by its anion. See polyatomic ion for a list of possible ions. For cations that take on multiple charges, the charge is written using Roman numerals in parentheses immediately following the element name. For example, Cu(NO) is "copper(II) nitrate", because the charge of two nitrate ions () is 2 × −1 = −2, and since the net charge of the ionic compound must be zero, the Cu ion has a 2+ charge. This compound is therefore copper(II) nitrate. In the case of cations with a +4 oxidation state, the only acceptable format for the Roman numeral 4 is IV and not IIII.
IUPAC nomenclature of inorganic chemistry | Naming simple ionic compounds
Ionic compounds containing hydrogen ions (H) are classified as acids, and those containing electropositive cations and basic anions ions hydroxide (OH) or oxide (O) are classified as bases. Other ionic compounds are known as salts and can be formed by acid–base reactions. If the compound is the result of a reaction between a strong acid and a weak base, the result is an acidic salt. If it is the result of a reaction between a strong base and a weak acid, the result is a basic salt. If it is the result of a reaction between a strong acid and a strong base, the result is a neutral salt.
Ionic compound | Acidity/basicity
If the compound's normal boiling point is higher, then that compound can exist as a liquid or solid at that given temperature at atmospheric external pressure, and will so exist in equilibrium with its vapor (if volatile) if its vapors are contained. If a compound's vapors are not contained, then some volatile compounds can eventually evaporate away in spite of their higher boiling points. In general, compounds with ionic bonds have high normal boiling points, if they do not decompose before reaching such high temperatures. Many metals have high boiling points, but not all. Very generally—with other factors being equal—in compounds with covalently bonded molecules, as the size of the molecule (or molecular mass) increases, the normal boiling point increases.
Boiling point | Boiling point as a reference property of a pure compound
Weak acids reacted with weak bases can produce ionic compounds with both the conjugate base ion and conjugate acid ion, such as ammonium acetate. Some ions are classed as amphoteric, being able to react with either an acid or a base. This is also true of some compounds with ionic character, typically oxides or hydroxides of less-electropositive metals (so the compound also has significant covalent character), such as zinc oxide, aluminium hydroxide, aluminium oxide and lead(II) oxide.
Ionic compound | Acidity/basicity
The use of the term hydrate is still acceptable e.g. NaSO·10HO, sodium sulfate decahydrate. The recommended method would be to name it sodium sulfate—water(1/10). Similarly other examples of lattice compounds are:
IUPAC nomenclature of inorganic chemistry 2005 | Naming of hydrates and similar lattice compounds
Salts of carboxylic acids are named following the usual cation-then-anion conventions used for ionic compounds in both IUPAC and common nomenclature systems. The name of the carboxylate anion is derived from that of the parent acid by replacing the "–oic acid" ending with "–oate." For example, , the sodium salt of benzoic acid (), is called sodium benzoate. Where an acid has both a systematic and a common name (like , for example, which is known as both acetic acid and as ethanoic acid), its salts can be named from either parent name. Thus, can be named as potassium acetate or as potassium ethanoate.
IUPAC nomenclature of organic chemistry | Carboxylates
Ionic compounds containing basic ions hydroxide (OH) or oxide (O) are classified as bases. Ionic compounds without these ions are also known as salts and can be formed by acid–base reactions. Ionic compounds can also be produced from their constituent ions by evaporation of their solvent, precipitation, freezing, a solid-state reaction, or the electron transfer reaction of reactive metals with reactive non-metals, such as halogen gases. Ionic compounds typically have high melting and boiling points, and are hard and brittle. As solids they are almost always electrically insulating, but when melted or dissolved they become highly conductive, because the ions are mobilized.
Ionic compound | Introduction
When the molecular size becomes that of a macromolecule, polymer, or otherwise very large, the compound often decomposes at high temperature before the boiling point is reached. Another factor that affects the normal boiling point of a compound is the polarity of its molecules. As the polarity of a compound's molecules increases, its normal boiling point increases, other factors being equal. Closely related is the ability of a molecule to form hydrogen bonds (in the liquid state), which makes it harder for molecules to leave the liquid state and thus increases the normal boiling point of the compound. Simple carboxylic acids dimerize by forming hydrogen bonds between molecules.
Boiling point | Boiling point as a reference property of a pure compound
The quoted boiling point in the table below is thus a prediction. Despite this situation, some sources describe it without comment as a known compound.
Hexafluoride | Binary hexafluorides
The word "ion" is the Greek , "ion", "going", the present participle of , "ienai", "to go". This term was introduced by English physicist and chemist Michael Faraday in 1834 for the then-unknown species that "goes" from one electrode to the other through an aqueous medium. In 1913 the crystal structure of sodium chloride was determined by William Henry Bragg and William Lawrence Bragg. This revealed that there were six equidistant nearest-neighbours for each atom, demonstrating that the constituents were not arranged in molecules or finite aggregates, but instead as a network with long-range crystalline order. Many other inorganic compounds were also found to have similar structural features.
Ionic compound | History of discovery
IUPAC, however, recommends against calling future compounds not yet discovered with a name ending with the word "acid". Indeed, acids can be called with names formed by adding the word "hydrogen" in front of the corresponding anion; for example, sulfuric acid could just as well be called "hydrogen sulfate" (or "dihydrogen sulfate"). In fact, the fully systematic name of sulfuric acid, according to IUPAC's rules, would be "dihydroxidodioxidosulfur" and that of the sulfate ion, "tetraoxidosulfate(2−)", Such names, however, are almost never used.
Oxyacid | Names of inorganic oxyacids
As previously discussed, ionic interactions require considerably more energy to break than hydrogen bonds, which in turn are require more energy than dipole–dipole interactions. The trends observed in their boiling points (figure 8) shows exactly the correlation expected, where sodium n-butoxide requires significantly more heat energy (higher temperature) to boil than n-butanol, which boils at a much higher temperature than diethyl ether. The heat energy required for a compound to change from liquid to gas is associated with the energy required to break the intermolecular forces each molecule experiences in its liquid state.
Non-covalent interaction | Boiling points
The Roman numerals in fact show the oxidation number, but in simple ionic compounds (i.e., not metal complexes) this will always equal the ionic charge on the metal. For a simple overview see , for more details see selected pages from IUPAC rules for naming inorganic compounds.
IUPAC nomenclature of inorganic chemistry | Naming simple ionic compounds
For type-I ionic binary compounds, the cation (a metal in most cases) is named first, and the anion (usually a nonmetal) is named second. The cation retains its elemental name (e.g., "iron" or "zinc"), but the suffix of the nonmetal changes to "-ide". For example, the compound LiBr is made of Li cations and Br anions; thus, it's called lithium bromide. The compound BaO, which is composed of Ba cations and O anions, is referred to as barium oxide. The oxidation state of each element is unambiguous. When these ions combine into a type-I binary compound, their equal-but-opposite charges are neutralized, so the compound's net charge is zero.
Chemical nomenclature | Type-I ionic binary compounds
Compositional names impart little structural information and are recommended for use when structural information is not available or does not need to be conveyed. Stoichiometric names are the simplest and reflect either the empirical formula or the molecular formula. The ordering of the elements follows the formal electronegativity list for binary compounds and electronegativity list to group the elements into two classes which are then alphabetically sequenced. The proportions are specified by di-, tri-, etc. (See IUPAC numerical multiplier.) Where there are known to be complex cations or anions these are named in their own right and then these names used as part of the compound name.
IUPAC nomenclature of inorganic chemistry 2005 | Compounds
For example, FeSO is named iron(2+) sulfate (with the 2+ charge on the Fe ions balancing the 2− charge on the sulfate ion), whereas Fe(SO) is named iron(3+) sulfate (because the two iron ions in each formula unit each have a charge of 3+, to balance the 2− on each of the three sulfate ions). Stock nomenclature, still in common use, writes the oxidation number in Roman numerals (... , −II, −I, 0, I, II, ...). So the examples given above would be named iron(II) sulfate and iron(III) sulfate respectively. For simple ions the ionic charge and the oxidation number are identical, but for polyatomic ions they often differ.
Ionic compound | Nomenclature
Type-II ionic binary compounds are those in which the cation does not have just one oxidation state. This is common among transition metals. To name these compounds, one must determine the charge of the cation and then write out the name as would be done with Type I Ionic Compounds, except that a Roman numeral (indicating the charge of the cation) is written in parentheses next to the cation name (this is sometimes referred to as Stock nomenclature). For example, take the compound FeCl. The cation, iron, can occur as Fe and Fe. In order for the compound to have a net charge of zero, the cation must be Fe so that the three Cl anions can be balanced out (3+ and 3− balance to 0).
Chemical nomenclature | Type-II ionic binary compounds
Some ionic compounds contain polyatomic ions, which are charged entities containing two or more covalently bonded types of atoms. It is important to know the names of common polyatomic ions; these include:
Chemical nomenclature | Type-II ionic binary compounds
Thus, this compound is called iron(III) chloride. Another example could be the compound PbS. Because the S anion has a subscript of 2 in the formula (giving a 4− charge), the compound must be balanced with a 4+ charge on the Pb cation (lead can form cations with a 4+ or a 2+ charge). Thus, the compound is made of one Pb cation to every two S anions, the compound is balanced, and its name is written as lead(IV) sulfide. An older system – relying on Latin names for the elements – is also sometimes used to name Type II Ionic Binary Compounds.
Chemical nomenclature | Type-II ionic binary compounds
Inorganic molecular compounds are named with a prefix (see list above) before each element. The more electronegative element is written last and with an "-ide" suffix. For example, HO (water) can be called "dihydrogen monoxide". Organic molecules do not follow this rule. In addition, the prefix "mono-" is not used with the first element; for example, SO is "sulfur dioxide", not "monosulfur dioxide". Sometimes prefixes are shortened when the ending vowel of the prefix "conflicts" with a starting vowel in the compound. This makes the name easier to pronounce; for example, CO is "carbon monoxide" (as opposed to "monooxide").
IUPAC nomenclature of inorganic chemistry | Naming molecular compounds
They have been found to hydrolyse. Because of their distinctive properties, ionic liquids have been investigated for many applications. Some ionic liquids can be distilled under vacuum conditions at temperatures near 300 °C. In the original work by Martyn Earle, et al., the authors wrongly concluded that the vapor was made up of individual, separated ions, but was later proven that the vapors formed consisted of ion pairs. Some ionic liquids (such as 1-butyl-3-methylimidazolium nitrate) generate flammable gases on thermal decomposition. Thermal stability and melting point depend on the liquid's components. The thermal stability of a task-specific ionic liquid, protonated betaine bis(trifluoromethanesulfonyl)imide is of about and N-butyl-N-methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide was thermally stable up to 640 K.
Ionic liquid | Characteristics
Ionic compounds can be produced from their constituent ions by evaporation, precipitation, or freezing. Reactive metals such as the alkali metals can react directly with the highly electronegative halogen gases to form an ionic product. They can also be synthesized as the product of a high temperature reaction between solids. If the ionic compound is soluble in a solvent, it can be obtained as a solid compound by evaporating the solvent from this electrolyte solution. As the solvent is evaporated, the ions do not go into the vapour, but stay in the remaining solution, and when they become sufficiently concentrated, nucleation occurs, and they crystallize into an ionic compound.
Ionic compound | Formation
Compounds with a similar structure: Compounds with similar chemistry:
Periodic acid | See also
The large family starts with borate, carbonate, nitrate, fluorate, aluminate, silicate, phosphate, sulfate, chlorate, titanate, vanadate, chromate, manganate, ferrate, percobaltate, germanate, arsenate, selenate, bromate, molybdate, pertechnate, perruthenate, stannate, antimonate, tellurate, iodate, perxenate, tungstate, plumbate, bismuthate. Also the partially deprotonated hydrogensulfate, hydrogenphosphate, dihydrogenphosphate, etc. Also phosphonate, sulfonate, etc. Also carboxylate ions such as formate, acetate, propionate, butyrate, isobutyrate; oxalate, etc. Also methanolate / methoxide, ethanolate / ethoxide, etc. Also cyanate, isocyanate, thiocyanate, fulminate. Sulfur oxoanions, thioacetate, thiolates. Chlorosulfate, chloroacetate, etc.
Ate complex | -ate suffix
Simple covalent binary inorganic compounds E""X"" are named as where X is more electronegative than E, using the IUPAC formal electronegativity order. For example, PS is called 十硫化四磷 (shíliúhuàsìlín) (literally: 'ten sulfur of four phosphorus', 'decasulfide of tetraphosphorus'). As in English nomenclature, if "m" = 1, the numerical prefix of E is usually dropped in covalent compounds. For example, CO is called 一氧化碳 (yīyǎnghuàtàn) (literally: 'one oxygen of carbon', 'monoxide of carbon'). However, for compounds named as salts, numerical prefixes are dropped altogether, as in English. Thus, calcium chloride, CaCl, is named 氯化钙 (literally: 'chloride of calcium'). There is also a Chinese analog of the "-ic"/-"ous" nomenclature for higher/lower oxidation states.
Chemical elements in East Asian languages | Usage in the nomenclature for simple inorganic compounds
Several organic molecules have semitrivial names where the suffixes "-ane" (for an alkane) or "-ene" (for an alkene) are added to a name based on the shape of the molecule. Some are pictured below. Other examples include barrelene (shaped like a barrel), fenestrane (having a window-pane motif), ladderane (a ladder shape), olympiadane (having a shape with the same topology as the Olympic rings) and quadratic acid (also known as squaric acid).
Trivial name | Shape-based
The compounds nitryl fluoride, NOF, and nitryl chloride, NOCl, are not nitronium salts but molecular compounds, as shown by their low boiling points (−72 °C and −6 °C respectively) and short N–X bond lengths (N–F 135 pm, N–Cl 184 pm). Addition of one electron forms the neutral nitryl radical, ; in fact, this is fairly stable and known as the compound nitrogen dioxide. The related negatively charged species is , the nitrite ion.
Nitronium ion | Related species
Organic compounds typically melt and many boil. In contrast, while inorganic materials generally can be melted, many do not boil, and instead tend to degrade. In earlier times, the melting point (m.p.) and boiling point (b.p.) provided crucial information on the purity and identity of organic compounds. The melting and boiling points correlate with the polarity of the molecules and their molecular weight. Some organic compounds, especially symmetrical ones, sublime. A well-known example of a sublimable organic compound is para-dichlorobenzene, the odiferous constituent of modern mothballs. Organic compounds are usually not very stable at temperatures above 300 °C, although some exceptions exist.
Organic chemistry | Melting and boiling properties
This is a simple way to control the concentration and ionic strength. The concentration of solutes affects many colligative properties, including increasing the osmotic pressure, and causing freezing-point depression and boiling-point elevation. Because the solutes are charged ions they also increase the electrical conductivity of the solution. The increased ionic strength reduces the thickness of the electrical double layer around colloidal particles, and therefore the stability of emulsions and suspensions. The chemical identity of the ions added is also important in many uses. For example, fluoride containing compounds are dissolved to supply fluoride ions for water fluoridation.
Ionic compound | Uses
Lavoisier proposed that elements be named after their properties. For the next 125 years, most chemists followed this suggestion, using Greek and Latin roots to compose the names; for example, hydrogen ("water-producing"), oxygen ("acid-producing"), nitrogen ("soda-producing"), bromine ("stink"), and argon ("no reaction") were based on Greek roots, while the names of iodine and chlorine were derived from the Greek words for their characteristic colors. Indium, rubidium, and thallium were similarly named for the colors of particular lines in their emission spectra. Iridium, which forms compounds of many different colors, takes its name from "iris", the Latin for "rainbow". The noble gases have all been named for their origin or properties.
Trivial name | Origins
Hydrates are ionic compounds that have absorbed water. They are named as the ionic compound followed by a numerical prefix and "-hydrate". The numerical prefixes used are listed below (see IUPAC numerical multiplier): For example, CuSO·5HO is "copper(II) sulfate pentahydrate".
IUPAC nomenclature of inorganic chemistry | Naming hydrates
The circumstances under which a compound will have ionic or covalent character can typically be understood using Fajans' rules, which use only charges and the sizes of each ion. According to these rules, compounds with the most ionic character will have large positive ions with a low charge, bonded to a small negative ion with a high charge. More generally HSAB theory can be applied, whereby the compounds with the most ionic character are those consisting of hard acids and hard bases: small, highly charged ions with a high difference in electronegativities between the anion and cation. This difference in electronegativities means that the charge separation, and resulting dipole moment, is maintained even when the ions are in contact (the excess electrons on the anions are not transferred or polarized to neutralize the cations).
Ionic compound | Bonding
Chemical nomenclature, replete as it is with compounds with complex names, is a repository for some names that may be considered unusual. A browse through the "Physical Constants of Organic Compounds" in the "CRC Handbook of Chemistry and Physics" (a fundamental resource) will reveal not just the whimsical work of chemists, but the sometimes peculiar compound names that occur as the consequence of simple juxtaposition. Some names derive legitimately from their chemical makeup, from the geographic region where they may be found, the plant or animal species from which they are isolated or the name of the discoverer. Some are given intentionally unusual trivial names based on their structure, a notable property or at the whim of those who first isolate them.
List of chemical compounds with unusual names | Introduction
As the number of chlorine atoms increases, the electronegativity of that end of the molecule increases, and the molecule adopts a progressively more ionic character: its density, boiling point and acidity all increase.
Chloroacetic acids | Properties
This naming method generally follows established IUPAC organic nomenclature. Hydrides of the main group elements (groups 13–17) are given "-ane" base name, e.g. borane (BH), oxidane (HO), phosphane (PH) (Although the name "phosphine" is also in common use, it is not recommended by IUPAC). The compound PCl would thus be named substitutively as trichlorophosphane (with chlorine "substituting"). However, not all such names (or stems) are derived from the element name. For example, NH is called "azane".
Chemical nomenclature | Substitutive nomenclature
In some cases the anions take on a simple cubic packing, and the resulting common structures observed are: Some ionic liquids, particularly with mixtures of anions or cations, can be cooled rapidly enough that there is not enough time for crystal nucleation to occur, so an ionic glass is formed (with no long-range order).
Ionic compound | Structure
Carbon dioxide is written CO; sulfur tetrafluoride is written SF. A few compounds, however, have common names that prevail. HO, for example, is usually called "water" rather than "dihydrogen monoxide", and NH is preferentially called "ammonia" rather than "nitrogen trihydride".
Chemical nomenclature | Type-III binary compounds
These anions are also associated with methane and acetylene, both very weak acids. With an electronegativity of 2.5, carbon prefers to form covalent bonds. A few carbides are covalent lattices, like carborundum (SiC), which resembles diamond. Nevertheless, even the most polar and salt-like of carbides are not completely ionic compounds.
Carbon | Inorganic compounds
As can be seen from the above plot of the logarithm of the vapor pressure vs. the temperature for any given pure chemical compound, its normal boiling point can serve as an indication of that compound's overall volatility. A given pure compound has only one normal boiling point, if any, and a compound's normal boiling point and melting point can serve as characteristic physical properties for that compound, listed in reference books. The higher a compound's normal boiling point, the less volatile that compound is overall, and conversely, the lower a compound's normal boiling point, the more volatile that compound is overall.
Boiling point | Boiling point as a reference property of a pure compound
The -ate suffix is applied with anions. The ionic charge value is included in the chemical formula but not as not part of the systematic name.
Boranes | Chemical formula and naming conventions
Simple cations formed by adding a hydron to a hydride of a halogen, chalcogen or pnictogen are named by adding the suffix "-onium" to the element's root: HN is ammonium, HO is oxonium, and HF is fluoronium. Ammonium was adopted instead of nitronium, which commonly refers to NO. If the cationic center of the hydride is not a halogen, chalcogen or pnictogen then the suffix "-ium" is added to the name of the neutral hydride after dropping any final 'e'. HC is methanium, HO-(O)-H is dioxidanium (HO-OH is dioxidane), and HN-(N)-H is diazanium (HN-NH is diazane).
IUPAC nomenclature of organic chemistry | Parent hydride cations
The following illustrate the principles. The 1:1:1:1 quaternary compound between bromine, chlorine, iodine and phosphorus: The ternary 2:1:5 compound of antimony, copper and potassium can be named in two ways depending on which element(s) are designated as electronegative.
IUPAC nomenclature of inorganic chemistry 2005 | Ternary compounds and beyond
Early terminology for compound chemicals followed similar rules to the naming of elements. The names could be based on the appearance of the substance, including all five senses. In addition, chemicals were named after the consistency, crystalline form, a person or place, its putative medical properties or method of preparation. Salt (sodium chloride) is soluble and is used to enhance the taste of food. Substances with similar properties came to be known as salts, in particular "Epsom salt" (magnesium sulfate, found in a bitter saline spring in the English town of Epsom). Ammonium (with the little-used formal name nitrogen trihydride) was first extracted from sal ammoniac, meaning "salt of Amun".
Trivial name | Inorganic chemistry
Monatomic anions: Polyatomic ions:
IUPAC nomenclature of inorganic chemistry | List of common ion names
The reaction products of with and are assumed to be molecular adducts rather than true salts. One notable chloryl compound is dichlorine hexoxide, which exists as an ionic compound more accurately described as "chloryl perchlorate", . It is a red fuming liquid under standard conditions.
Chloryl | Compounds
Room-temperature ionic liquids (RTILs) consist of bulky and asymmetric organic cations such as 1-alkyl-3-methylimidazolium, 1-alkylpyridinium, "N"-methyl-"N"-alkylpyrrolidinium and ammonium ions. Phosphonium cations are less common, but offer some advantageous properties. A wide range of anions are employed, ranging from simple halides, which generally suffer high melting points, to inorganic anions such as tetrafluoroborate and hexafluorophosphate, and to large organic anions like bistriflimide, triflate or tosylate. There are also many potential uses of ionic liquids with simple non-halogenated organic anions such as formate, alkylsulfate, alkylphosphate or glycolate. The melting point of 1-butyl-3-methylimidazolium tetrafluoroborate is about and it is a colorless liquid with high viscosity at room temperature.
Ionic liquid | Room-temperature varieties
This process occurs widely in nature, and is the means of formation of the evaporite minerals. Another method of recovering the compound from solution involves saturating a solution at high temperature and then reducing the solubility by reducing the temperature until the solution is supersaturated and the solid compound nucleates. Insoluble ionic compounds can be precipitated by mixing two solutions, one with the cation and one with the anion in it. Because all solutions are electrically neutral, the two solutions mixed must also contain counterions of the opposite charges. To ensure that these do not contaminate the precipitated ionic compound, it is important to ensure they do not also precipitate.
Ionic compound | Formation
If the solvation energy exceeds the lattice energy, the negative net enthalpy change of solution provides a thermodynamic drive to remove ions from their positions in the crystal and dissolve in the liquid. In addition, the entropy change of solution is usually positive for most solid solutes like ionic compounds, which means that their solubility increases when the temperature increases. There are some unusual ionic compounds such as cerium(III) sulfate, where this entropy change is negative, due to extra order induced in the water upon solution, and the solubility decreases with temperature.
Ionic compound | Solubility
Compounds consisting of oppositely charged ions are known as ionic compounds, or salts.
Chemical substance | Chemical compounds
Some classical compounds are variants of one base. Some are also free words, such as "mania" in "dipsomania" and "phobia" in "claustrophobia". Some are composites of other elements, such as "encephalo-" brain, from "en-" in, "-cephal-" head; and "-ectomy" cutting out, from "ec-" out, "-tom-" cut, "-y", a noun-forming suffix that means "process of".
Classical compound | Variants
If both acyl groups are the same, then the name of the carboxylic acid with the word acid replaced with anhydride and IUPAC name consists of two words. If the acyl groups are different, then they are named in alphabetical order in the same way , with anhydride replacing acid and IUPAC name consists of three words. For example, CH3CO-O-OCCH3 is called Ethanoic Anhydride, CH3CO-O-OCCH2CH3 is called Ethanoic Propanoic Anhydride.
IUPAC nomenclature of organic chemistry | Acid Anhydrides
Different compounds that obey the octet rule (sp-elements) and hydrogen can be placed on the triangle. Unfortunately, d-elements cannot be analysed using van Arkel-Ketelaar triangle, as their electronegativity is so high that it is taken as a constant. Using electronegativity - two compound average electronegativity on x-axis and electronegativity difference on y-axis, we can rate the dominant bond between the compounds. Example is here On the right side (from ionic to covalent) should be compounds with varying difference in electronegativity. The compounds with equal electronegativity, such as Cl (chlorine) are placed in the covalent corner , while the ionic corner has compounds with large electronegativity difference, such as NaCl (table salt).
Van Arkel–Ketelaar triangle | Usage
The elements included light; caloric (matter of heat); the principles of oxygen, hydrogen, and azote (nitrogen); carbon; sulfur; phosphorus; the yet unknown "radicals" of muriatic acid (hydrochloric acid), boric acid, and "fluoric" acid; 17 metals; 5 earths (mainly oxides of yet unknown metals such as magnesia, baria, and strontia); three alkalies (potash, soda, and ammonia); and the "radicals" of 19 organic acids. The acids, regarded in the new system as compounds of various elements with oxygen, were given names which indicated the element involved together with the degree of oxygenation of that element, for example sulfuric and sulfurous acids, phosphoric and phosphorous acids, nitric and nitrous acids, the "ic" termination indicating acids with a higher proportion of oxygen than those with the "ous" ending.
Antoine Lavoisier | Chemical nomenclature
In organic chemistry, Carnelley's rule, established in 1882 by Thomas Carnelley, states that "high molecular symmetry is associated with high melting point". Carnelley based his rule on examination of 15,000 chemical compounds. For example, for three structural isomers with molecular formula CH the melting point increases in the series isopentane −160 °C (113 K) n-pentane −129.8 °C (143 K) and neopentane −16.4 °C (256.8 K). Likewise in xylenes and also dichlorobenzenes the melting point increases in the order meta, ortho and then para. Pyridine has a lower symmetry than benzene hence its lower melting point but the melting point again increases with diazine and triazines.
Melting point | Carnelley's rule
Any salt that melts without decomposing or vaporizing usually yields an ionic liquid. Sodium chloride (NaCl), for example, melts at into a liquid that consists largely of sodium cations () and chloride anions (). Conversely, when an ionic liquid is cooled, it often forms an ionic solid—which may be either crystalline or glassy. The ionic bond is usually stronger than the Van der Waals forces between the molecules of ordinary liquids. For that reason, common salts tend to melt at higher temperatures than other solid molecules. Some salts are liquid at or below room temperature. Examples include compounds based on the 1-ethyl-3-methylimidazolium (EMIM) cation and include: EMIM:Cl, EMIM dicyanamide, ()()·, that melts at ; and 1-butyl-3,5-dimethylpyridinium bromide which becomes a glass below .
Ionic liquid | Introduction
The compressibility of an ionic compound is strongly determined by its structure, and in particular the coordination number. For example, halides with the caesium chloride structure (coordination number 8) are less compressible than those with the sodium chloride structure (coordination number 6), and less again than those with a coordination number of 4.
Ionic compound | Compressibility
In this system, the metal (instead of a Roman numeral next to it) has an "-ic" or "-ous" suffix added to it to indicate its oxidation state ("-ous" for lower, "-ic" for higher). For example, the compound FeO contains the Fe cation (which balances out with the O anion). Since this oxidation state is lower than the other possibility (Fe), this compound is sometimes called ferrous oxide. For the compound, SnO, the tin ion is Sn (balancing out the 4− charge on the two O anions), and because this is a higher oxidation state than the alternative (Sn), this compound is called stannic oxide.
Chemical nomenclature | Type-II ionic binary compounds
The stoichiometric name is followed by the number of hydrogen atoms in brackets. For example BH, diborane(6). More structural information can be conveyed by adding the "structural descriptor" "closo"-, "nido"-, "arachno"-, "hypho"-, "klado"- prefixes. There is a fully systematic method of numbering the atoms in the boron hydride clusters, and a method of describing the position of bridging hydrogen atoms using the μ symbol.
IUPAC nomenclature of inorganic chemistry 2005 | Boron hydrides
The boiling point is 45.5 °C, and the melting point is -122.9. The predicted heat of formation for liquid trimethyldiborane is ΔH=-48 kcal/mol, and for the gas -41 kcal/mol. Heat of vapourisation ΔH was measured at 7.0 kcal/mol. A gas chromatograph can be used to determine the amounts of the methyl boranes in a mixture. The order they pass through are diborane, monomethyldiborane, trimethylborane, 1,1-dimethyldiborane, 1,2-dimethyldiborane, trimethyldiborane, and last tetramethyldiborane.
Trimethyldiborane | Properties
Its boiling point is expected to be about 80±30 °C, so that it is probably neither noble nor a gas; as a liquid it is expected to have a density of about 5 g/cm. It is expected to have a barely positive electron affinity (estimated as 5 kJ/mol) and a moderate ionisation energy of about 860 kJ/mol, which is rather low for a nonmetal and close to those of the metalloids tellurium and astatine. The oganesson fluorides OgF and OgF are expected to show significant ionic character, suggesting that oganesson may have at least incipient metallic properties. The oxides of oganesson, OgO and OgO, are predicted to be amphoteric.
Nonmetal | Group 18
In the higher oxidation states of the pnictogens, chalcogens, halogens, and noble gases there are oxoacids in which the central atom is attached to oxide ions and hydroxide ions. Examples include phosphoric acid HPO, and sulfuric acid HSO. In these compounds one or more hydroxide groups can dissociate with the liberation of hydrogen cations as in a standard Brønsted–Lowry acid. Many oxoacids of sulfur are known and all feature OH groups that can dissociate. Telluric acid is often written with the formula HTeO·2HO but is better described structurally as Te(OH). "Ortho"-periodic acid can lose all its protons, eventually forming the periodate ion [IO].
Hydroxide | Other main-group elements
The pure compound has a melting point of −86.8 °C and a boiling point of 23.5 °C, so it is volatile at ambient temperatures.
Isocyanic acid | Physical
It is difficult or impossible to find compounds with more than one IUPAC name. This is because shorter chains attached to longer chains are prefixes and the convention includes brackets. Numbers in the name, referring to which carbon a group is attached to, should be as low as possible so that 1- is implied and usually omitted from names of organic compounds with only one side-group. Symmetric compounds will have two ways of arriving at the same name.
Alkane | Nomenclature
The simplest systematic name of water is "hydrogen oxide". This is analogous to related compounds such as hydrogen peroxide, hydrogen sulfide, and deuterium oxide (heavy water). Using chemical nomenclature for type I ionic binary compounds, water would take the name "hydrogen monoxide", but this is not among the names published by the International Union of Pure and Applied Chemistry (IUPAC). Another name is "dihydrogen monoxide", which is a rarely used name of water, and mostly used in the dihydrogen monoxide parody. Other systematic names for water include "hydroxic acid", "hydroxylic acid", and "hydrogen hydroxide", using acid and base names. None of these exotic names are used widely.
Properties of water | Nomenclature
When compounds contain more than one functional group, the order of precedence determines which groups are named with prefix or suffix forms. The table below shows common groups in decreasing order of precedence. The highest-precedence group takes the suffix, with all others taking the prefix form. However, double and triple bonds only take suffix form (-en and -yn) and are used with other suffixes. Prefixed substituents are ordered alphabetically (excluding any modifiers such as di-, tri-, etc.), e.g. chlorofluoromethane, "not" fluorochloromethane. If there are multiple functional groups of the same type, either prefixed or suffixed, the position numbers are ordered numerically (thus ethane-1,2-diol, "not" ethane-2,1-diol.) The "N" position indicator for amines and amides comes before "1", e.g.
IUPAC nomenclature of organic chemistry | Order of precedence of groups
In the following table, the entropy terms are calculated from the experimental values of p"K" and Δ"H". The data were critically selected and refer to 25 °C and zero ionic strength, in water.
Acid dissociation constant | Thermodynamics
Most ionic compounds are very brittle. Once they reach the limit of their strength, they cannot deform malleably, because the strict alignment of positive and negative ions must be maintained. Instead the material undergoes fracture via cleavage. As the temperature is elevated (usually close to the melting point) a ductile–brittle transition occurs, and plastic flow becomes possible by the motion of dislocations.
Ionic compound | Brittleness
Another convention for the naming of compounds is the "common name", which is a shorter name and it gives less information about the compound. An example of a common name is terpineol, the name of which can tell us only that it is an alcohol (because the suffix "-ol" is in the name) and it should then have a hydroxy (–OH) group attached to it. An example of the IUPAC method is given in the adjacent image. In this example the base name is listed first, which indicates the total number of carbons in both rings including the carbons making up the shared edge (e.g., "heptane", which means "hepta-" or 7 carbons, and "-ane", which indicates only single bonding between carbons).
Cycloalkane | Nomenclature
As required for all separation techniques, ionic liquids exhibit selectivity towards one or more of the phases of a mixture. 1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF) is a room-temperature ionic liquid that was identified early on as a viable substitute for volatile organic solvents in liquid-liquid separations. Other [PF]- and [BF]- containing ionic liquids have been studied for their CO absorption properties, as well as 1-ethyl-3-methylimidazolium (EMIM) and unconventional cations like trihexyl(tetradecyl) phosphonium ([P]). Selection of different anion and cation combinations in ionic liquids affects their selectivity and physical properties. Additionally, the organic cations in ionic liquids can be "tuned" by changing chain lengths or by substituting radicals.
Ionic liquids in carbon capture | Tunability
IUPAC naming for Borinic acid is a unique name for acid. The anhydrides are named diboroxanes, HBOBH, as the base compound and H being able to be substituted, e.g. tetraethyldiboroxane, as the anhydride for diethylborinic acid. Organic naming standard in the bluebook allows skeletal replacement naming where the name is shorter, 3-borapentan-3-ol versus diethyl borinic acid. The grouping -BH-O-BH is called diboroxanyl. Substituting sulfur for oxygen gives borinothioic acid (HBSH). (dimethylboranyl)oxy is used for the group (CH)B-O− and methyl(hydroxy)boranyl for the grouping CHB(OH)-.
Borinic acid | Naming
Two major drawbacks for some applications were moisture sensitivity and acidity or basicity. In 1992, Wilkes and Zawarotko obtained ionic liquids with 'neutral' weakly coordinating anions such as hexafluorophosphate () and tetrafluoroborate (), allowing a much wider range of applications. Although many classical ILs are hexafluorophosphate and tetrafluoroborate salts, bistriflimide are also popular.
Ionic liquid | History
Contrary to the usual English style for parentheses, there is no space between the end of the element name and the opening parenthesis: for AgF, the correct style is "silver(I) fluoride" not "silver (I) fluoride". Where there is no ambiguity about the oxidation state of an element in a compound, it is not necessary to indicate it with Roman numerals: hence for NaCl, sodium chloride will suffice; sodium(I) chloride(−I) is unnecessarily long and such usage is very rare.
Stock nomenclature | Style
For ions, the charge on a particular atom may be denoted with a right-hand superscript. For example, Na, or Cu. The total charge on a charged molecule or a polyatomic ion may also be shown in this way. For example: HO or SO. Note that + and - are used in place of +1 and -1, respectively. For more complex ions, brackets [ ] are often used to enclose the ionic formula, as in [BH], which is found in compounds such as Cs[BH]. Parentheses ( ) can be nested inside brackets to indicate a repeating unit, as in [Co(NH)]Cl. Here, (NH) indicates that the ion contains six NH groups bonded to cobalt, and [ ] encloses the entire formula of the ion with charge +3.
Chemical formula | Ions in condensed formulae
Other chemical compounds with "triiodide" in their name may contain three iodide centers that are not bonded to each other as the triiodide ion, but exist instead as separate iodine atoms or iodide ions. Examples include nitrogen triiodide (NI) and phosphorus triiodide (PI), where individual iodine atoms are covalently bonded to a central atom. As some cations have the theoretical possibility to form compounds with both triiodide and iodide ions, such as ammonium, compounds containing iodide anions in a 3:1 stoichiometric ratio should only be referred to as triiodides in cases where the triiodide anion is present. It may also be helpful to indicate the oxidation number of a metal cation, where appropriate.
Triiodide | Nomenclature
An alternative to using HF and HSO as alkylation catalysts is the use of ionic liquid (IL). ILs are liquid salts that have melting points below 100 °C. They exhibit strong acid properties, so they can be used as acid catalysis without using conventional liquid acids. Ionic liquids are salts in liquid state, composed mostly of ions that convert C4 paraffins and other olefins into excellent gasoline-range blending products. Many parameters are available for fine-tuning IL properties for specific applications, and the choice of cation and anion affects the IL's physical properties, such as melting point, viscosity, density, water solubility, and reactivity.
Alkylation unit | Ionic liquids
That is, if some excess of the acid is present in the mixture the density increases.
Protic ionic liquid | Properties
The following list has substances known to be gases, but with an unknown boiling point.
List of gases | Known as gas
NaCl, for example), temperature, and the common ion effect. One can calculate the amount of AgCl that will dissolve in 1 liter of water, some algebra is required.
Solubility | Solubility of ionic compounds in water
The recommendations give a full list of acceptable names for common acids and related anions. A selection from this list is shown below.
IUPAC nomenclature of inorganic chemistry 2005 | List of acceptable names
This list is sorted by boiling point of gases in ascending order, but can be sorted on different values. "sub" and "triple" refer to the sublimation point and the triple point, which are given in the case of a substance that sublimes at 1 atm; "dec" refers to decomposition.
List of gases | List
The lower oxidation state is marked with the character 亚 (yà, 'minor; secondary'). For example FeCl and FeCl are 氯化亚铁 and 氯化铁, respectively. In a four-way contrast, "hypo-" and "per-" are marked with 次 (cì, 'inferior; following') and 高 (gāo, 'high, upper'), respectively. For example, the acids HClO"" ("n" = 1, 2, 3, 4) are called 次氯酸 ("n" = 1), 亚氯酸 ("n" = 2), 氯酸 ("n" = 3), and 高氯酸 ("n" = 4). In this example, the character 酸 (suān, 'sour') means (organic or inorganic) acid. The more modern Stock nomenclature in which oxidation state is explicitly specified can also be used: thus, tin(IV) oxide (SnO) is simply 氧化锡(IV).
Chemical elements in East Asian languages | Usage in the nomenclature for simple inorganic compounds
Type-III binary compounds are covalently bonded. Covalent bonding occurs between nonmetal elements. Covalently-bonded compounds are also known as "molecules". In the compound, the first element is named first and with its full elemental name. The second element is named as if it were an anion (root name of the element + "-ide" suffix). Then, prefixes are used to indicate the numbers of each atom present: these prefixes are "mono-" (one), "di-" (two), "tri-" (three), "tetra-" (four), "penta-" (five), "hexa-" (six), "hepta-" (seven), "octa-" (eight), "nona-" (nine), and "deca-" (ten). The prefix "mono-" is never used with the first element. Thus, NCl is called nitrogen trichloride, PO is called diphosphorus pentoxide (the "a" of the "penta-" prefix is dropped before the vowel for easier pronunciation), and BF is called boron trifluoride.
Chemical nomenclature | Type-III binary compounds
If the two solutions have hydrogen ions and hydroxide ions as the counterions, they will react with one another in what is called an acid–base reaction or a neutralization reaction to form water. Alternately the counterions can be chosen to ensure that even when combined into a single solution they will remain soluble as spectator ions.
Ionic compound | Formation
Positively charged ions are called cations and negatively charged ions are called anions. The cation is always named first. Ions can be metals, non-metals or polyatomic ions. Therefore, the name of the metal or positive polyatomic ion is followed by the name of the non-metal or negative polyatomic ion. The positive ion retains its element name whereas for a single non-metal anion the ending is changed to "-ide". When the metal has more than one possible ionic charge or oxidation number the name becomes ambiguous. In these cases the oxidation number (the same as the charge) of the metal ion is represented by a Roman numeral in parentheses immediately following the metal ion name.
IUPAC nomenclature of inorganic chemistry | System
The two tables below show some examples of different compounds, their valence diagrams, and the valences for each element of the compound.
Valence (chemistry) | Description
The suffix -ane in organic chemistry forms the names of organic compounds where the -C-C- group has been attributed the highest priority according to the rules of organic nomenclature. Such organic compounds are called alkanes. They are saturated hydrocarbons. The names of the saturated hydrides of non-metals end with the suffix -ane: the hydrides of silicon are called silanes SiH; the hydrides of boron are boranes BH. The final "-e" is dropped before a suffix that starts with a vowel, e.g. "propanol".
-ane | Introduction
Some compounds decompose at higher temperatures before reaching their normal boiling point, or sometimes even their melting point. For a stable compound, the boiling point ranges from its triple point to its critical point, depending on the external pressure. Beyond its triple point, a compound's normal boiling point, if any, is higher than its melting point. Beyond the critical point, a compound's liquid and vapor phases merge into one phase, which may be called a superheated gas. At any given temperature, if a compound's normal boiling point is lower, then that compound will generally exist as a gas at atmospheric external pressure.
Boiling point | Boiling point as a reference property of a pure compound
In organic chemistry, some trivial names derive from a notable property of the thing being named. For instance, lecithin, the common name for phosphatidylcholine, was originally isolated from egg yolk. The word is coined from the Greek λέκιθος (lékithos) for "yolk". Many trivial names continue to be used because their sanctioned equivalents are considered too cumbersome for everyday use. For example, "tartaric acid", a compound found in wine, has a systematic name of 2,3-dihydroxybutanedioic acid. The pigment β-Carotene has an IUPAC name of 1,3,3-trimethyl-2-[(1E,3E,5E,7E,9E,11E,13E,15E,17E)-3,7,12,16-tetramethyl-18-(2,6,6-trimethylcyclohexen-1-yl)octadeca-1,3,5,7,9,11,13,15,17-nonaenyl]cyclohexene. However, the trivial name can be potentially confusing. Based on its name, one might come to the conclusion that the molecule theobromine contains one or more bromine atoms.
Trivial name | Organic chemistry
Data obtained from "CRC Handbook of Chemistry (Page 2117)" Azeotropic mixture
Ethanol (data page) | Boiling points of aqueous solutions
This naming method generally follows established IUPAC organic nomenclature. Hydrides of the main group elements (groups 13–17) are given "-ane" base names, e.g. borane, BH. Acceptable alternative names for some of the parent hydrides are water rather than oxidane and ammonia rather than azane. In these cases the base name is intended to be used for substituted derivatives.This section of the recommendations covers the naming of compounds containing rings and chains.
IUPAC nomenclature of inorganic chemistry 2005 | Substitutive nomenclature
(The term used in the original text, "hydroxyl acid", is a non-standard name.) Under the 2005 revisions of IUPAC nomenclature of inorganic chemistry, there is no single correct name for every compound. The primary function of chemical nomenclature is to ensure that each name refers, unambiguously, to a single substance. It is considered less important to ensure that each substance should have a single unambiguous name, although the number of acceptable names is limited. "Water" is one acceptable name for this compound, even though it is neither a systematic nor an international name and is specific to just one phase of the compound (its liquid form).
Dihydrogen monoxide parody | Molecular terminology and naming conventions
Monatomic cations are named by taking the element name and following it with the charge in brackets e.g Sometimes an abbreviated form of the element name has to be taken, e.g. germide for germanium as germanide refers to . Polyatomic cations of the same element are named as the element name preceded by di-, tri-, etc., e.g.: Polyatomic cations made up of different elements are named either substitutively or additively, e.g.:
IUPAC nomenclature of inorganic chemistry 2005 | Cations