Related literature {#sec1}
==================

For a related structure, see: Naz *et al.* (2010[@bb6]). For graph-set notation, see: Bernstein *et al.* (1995[@bb1]).

Experimental {#sec2}
============

 {#sec2.1}

### Crystal data {#sec2.1.1}

C~7~H~8~NO~4~ ^+^·Cl^−^·2H~2~O*M* *~r~* = 241.63Triclinic,*a* = 6.0285 (8) Å*b* = 7.9597 (8) Å*c* = 10.9570 (13) Åα = 100.135 (5)°β = 97.162 (4)°γ = 92.921 (5)°*V* = 512.10 (11) Å^3^*Z* = 2Mo *K*α radiationμ = 0.38 mm^−1^*T* = 296 K0.28 × 0.15 × 0.10 mm

### Data collection {#sec2.1.2}

Bruker Kappa APEXII CCD diffractometerAbsorption correction: multi-scan (*SADABS*; Bruker, 2005[@bb2]) *T* ~min~ = 0.935, *T* ~max~ = 0.9658850 measured reflections2548 independent reflections1853 reflections with *I* \> 2σ(*I*)*R* ~int~ = 0.039

### Refinement {#sec2.1.3}

*R*\[*F* ^2^ \> 2σ(*F* ^2^)\] = 0.044*wR*(*F* ^2^) = 0.115*S* = 1.032548 reflections139 parametersH-atom parameters constrainedΔρ~max~ = 0.40 e Å^−3^Δρ~min~ = −0.27 e Å^−3^

 {#d5e572}

Data collection: *APEX2* (Bruker, 2009[@bb3]); cell refinement: *SAINT* (Bruker, 2009[@bb3]); data reduction: *SAINT*; program(s) used to solve structure: *SHELXS97* (Sheldrick, 2008[@bb7]); program(s) used to refine structure: *SHELXL97* (Sheldrick, 2008[@bb7]); molecular graphics: *ORTEP-3 for Windows* (Farrugia, 1997[@bb4]) and *PLATON* (Spek, 2009[@bb8]); software used to prepare material for publication: *WinGX* (Farrugia, 1999[@bb5]) and *PLATON*.

Supplementary Material
======================

Crystal structure: contains datablocks global, I. DOI: [10.1107/S1600536811000559/dn2650sup1.cif](http://dx.doi.org/10.1107/S1600536811000559/dn2650sup1.cif)

Structure factors: contains datablocks I. DOI: [10.1107/S1600536811000559/dn2650Isup2.hkl](http://dx.doi.org/10.1107/S1600536811000559/dn2650Isup2.hkl)

Additional supplementary materials: [crystallographic information](http://scripts.iucr.org/cgi-bin/sendsupfiles?dn2650&file=dn2650sup0.html&mime=text/html); [3D view](http://scripts.iucr.org/cgi-bin/sendcif?dn2650sup1&Qmime=cif); [checkCIF report](http://scripts.iucr.org/cgi-bin/paper?dn2650&checkcif=yes)

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: [DN2650](http://scripts.iucr.org/cgi-bin/sendsup?dn2650)).

The authors acknowledge the provision of funds for the purchase of the diffractometer and encouragement by Dr Muhammad Akram Chaudhary, Vice Chancellor, University of Sargodha. Pakistan.

Comment
=======

Recently we have reported the crystal structure of 5-carboxy-2,4-dihydroxyanilinium chloride (Naz *et al.*, 2010). The title compound (I, Fig. 1) has been prepared in a slightly different way.

In (I), the organic group (C1---C7/O1---O4/N1) is planar with r. m. s. deviation of 0.0164 Å. In the organic part, there exist a strong intramolecular H-bond of O---H···O type (Table 1, Fig. 1) completing an S(6) ring motif (Bernstein *et al.*, 1995). In the title compound, the Cl^-^ anion is penta coordinated due to H-bondings of N---H···Cl and O---H···Cl types (Table 1, Fig. 2). The NH~3~^+^ ion makes H-bonding with the both water molecules and the Cl^-^ ion. Due to these strong H-bondings the molecules are stabilized in the form of three-dimensional polymeric network (Table 1, Fig. 2). There does not exist any π···π or C---H···π interaction.

Experimental {#experimental}
============

Concentrated nitric acid (2 mL, 67%) was added drop by drop to β-resorcylic acid (1 g, 97%, 6.3 mmol) in a round bottom flask. The mixture was protected from moisture by CaCl~2~ (anhydrous) tube and was allowed to stand for 12 h at room temperature. Then reaction mixture was diluted with water. The crude material was filtered and recrystallized from water to affoard the 5-nitro-β-resorcylic acid.

Then a mixture of 5-nitro-β-resorcylic acid (1.5 g, 7.5 mmol), tin (3 g, 25 mmol) and absolute ethanol (5 ml) were taken in a 100 ml round bottom flask and passed HCl gas under reflux with stirring for 1 h. The completion of reaction was monitored by TLC. The reaction mixture was filtered to remove any unreacted tin. Filtrate was kept for seven days to afford light brown needles of (I).

Refinement {#refinement}
==========

All H atoms attached to C atoms, N atom and hydroxyl O atoms were fixed geometrically and treated as riding with C---H = 0.93 Å (C), N---H = 0.89 Å and

O-H = 0.82Å with U~iso~(H) = 1.2U~eq~(C) and U~iso~(H) = 1.5U~eq~(N,O). H atoms of water molecules were located in difference Fourier maps and included in the subsequent refinement using restraints (O-H= 0.85 (1)Å and H···H= 1.40 (2)Å) with U~iso~(H) = 1.5U~eq~(O). In the last cycles of refinement, they were treated as riding on their parent O atoms.

Figures
=======

![View of the title compound with the atom numbering scheme. The displacement ellipsoids are drawn at the 50% probability level. H-atoms are shown as small spheres of arbitrary radii. The dotted line represents the intramolecular H-bonding.](e-67-0o299-fig1){#Fap1}

![The partial packing (PLATON; Spek, 2009) which shows that molecules form various ring motifs and molecules are interlinked through H-bondings to form three dimensional polymeric network.](e-67-0o299-fig2){#Fap2}

Crystal data {#tablewrapcrystaldatalong}
============

  ------------------------------- ---------------------------------------
  C~7~H~8~NO~4~^+^·Cl^−^·2H~2~O   *Z* = 2
  *M~r~* = 241.63                 *F*(000) = 252
  Triclinic, *P*1                 *D*~x~ = 1.567 Mg m^−3^
  Hall symbol: -P 1               Mo *K*α radiation, λ = 0.71073 Å
  *a* = 6.0285 (8) Å              Cell parameters from 1853 reflections
  *b* = 7.9597 (8) Å              θ = 1.9--28.4°
  *c* = 10.9570 (13) Å            µ = 0.38 mm^−1^
  α = 100.135 (5)°                *T* = 296 K
  β = 97.162 (4)°                 Needle, brown
  γ = 92.921 (5)°                 0.28 × 0.15 × 0.10 mm
  *V* = 512.10 (11) Å^3^          
  ------------------------------- ---------------------------------------

Data collection {#tablewrapdatacollectionlong}
===============

  ------------------------------------------------------------ --------------------------------------
  Bruker Kappa APEXII CCD diffractometer                       2548 independent reflections
  Radiation source: fine-focus sealed tube                     1853 reflections with *I* \> 2σ(*I*)
  graphite                                                     *R*~int~ = 0.039
  Detector resolution: 7.50 pixels mm^-1^                      θ~max~ = 28.4°, θ~min~ = 1.9°
  ω scans                                                      *h* = −8→8
  Absorption correction: multi-scan (*SADABS*; Bruker, 2005)   *k* = −10→8
  *T*~min~ = 0.935, *T*~max~ = 0.965                           *l* = −14→14
  8850 measured reflections                                    
  ------------------------------------------------------------ --------------------------------------

Refinement {#tablewraprefinementdatalong}
==========

  ------------------------------------- -------------------------------------------------------------------------------------------------
  Refinement on *F*^2^                  Primary atom site location: structure-invariant direct methods
  Least-squares matrix: full            Secondary atom site location: difference Fourier map
  *R*\[*F*^2^ \> 2σ(*F*^2^)\] = 0.044   Hydrogen site location: inferred from neighbouring sites
  *wR*(*F*^2^) = 0.115                  H-atom parameters constrained
  *S* = 1.03                            *w* = 1/\[σ^2^(*F*~o~^2^) + (0.0571*P*)^2^ + 0.0225*P*\] where *P* = (*F*~o~^2^ + 2*F*~c~^2^)/3
  2548 reflections                      (Δ/σ)~max~ \< 0.001
  139 parameters                        Δρ~max~ = 0.40 e Å^−3^
  0 restraints                          Δρ~min~ = −0.27 e Å^−3^
  ------------------------------------- -------------------------------------------------------------------------------------------------

Special details {#specialdetails}
===============

  -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
  Refinement. Refinement of *F*^2^ against ALL reflections. The weighted *R*-factor *wR* and goodness of fit *S* are based on *F*^2^, conventional *R*-factors *R* are based on *F*, with *F* set to zero for negative *F*^2^. The threshold expression of *F*^2^ \> σ(*F*^2^) is used only for calculating *R*-factors(gt) *etc*. and is not relevant to the choice of reflections for refinement. *R*-factors based on *F*^2^ are statistically about twice as large as those based on *F*, and *R*- factors based on ALL data will be even larger.
  -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å^2^) {#tablewrapcoords}
==================================================================================================

  ----- ------------- --------------- -------------- -------------------- --
        *x*           *y*             *z*            *U*~iso~\*/*U*~eq~   
  O1    0.2807 (3)    0.0789 (2)      0.38672 (13)   0.0395 (4)           
  H1    0.3127        0.0453          0.3164         0.059\*              
  O2    −0.0155 (3)   0.1663 (2)      0.27792 (13)   0.0454 (4)           
  O3    −0.2957 (3)   0.35281 (19)    0.40596 (13)   0.0401 (4)           
  H3    −0.2501       0.3044          0.3424         0.060\*              
  O4    −0.1327 (3)   0.4424 (2)      0.84841 (13)   0.0415 (4)           
  H4A   −0.2380       0.5033          0.8442         0.062\*              
  N1    0.2345 (3)    0.2711 (2)      0.84317 (14)   0.0306 (4)           
  H1A   0.3302        0.1906          0.8294         0.046\*              
  H1B   0.1449        0.2439          0.8965         0.046\*              
  H1C   0.3104        0.3712          0.8755         0.046\*              
  C1    0.0937 (4)    0.1574 (2)      0.37826 (18)   0.0303 (5)           
  C2    0.0302 (3)    0.2322 (2)      0.50004 (17)   0.0268 (4)           
  C3    −0.1622 (4)   0.3252 (2)      0.50731 (18)   0.0284 (4)           
  C4    −0.2215 (3)   0.3963 (2)      0.62285 (18)   0.0303 (5)           
  H4    −0.3489       0.4570          0.6270         0.036\*              
  C5    −0.0912 (3)   0.3766 (2)      0.73114 (18)   0.0286 (5)           
  C6    0.0990 (3)    0.2839 (2)      0.72445 (17)   0.0248 (4)           
  C7    0.1595 (3)    0.2145 (2)      0.61147 (17)   0.0259 (4)           
  H7    0.2879        0.1547          0.6086         0.031\*              
  O5    0.9425 (3)    0.17641 (17)    0.00957 (13)   0.0372 (4)           
  H5A   0.9959        0.1488          0.0794         0.056\*              
  H5B   0.8641        0.2602          0.0303         0.056\*              
  O6    0.4319 (3)    −0.02049 (19)   0.16590 (14)   0.0427 (4)           
  H6A   0.4697        0.0818          0.1525         0.064\*              
  H6B   0.3236        −0.0641         0.1078         0.064\*              
  Cl1   0.53107 (9)   0.35035 (6)     0.11554 (5)    0.03442 (17)         
  ----- ------------- --------------- -------------- -------------------- --

Atomic displacement parameters (Å^2^) {#tablewrapadps}
=====================================

  ----- ------------- ------------- ------------- ------------ ------------- ------------
        *U*^11^       *U*^22^       *U*^33^       *U*^12^      *U*^13^       *U*^23^
  O1    0.0407 (10)   0.0515 (9)    0.0269 (8)    0.0127 (7)   0.0097 (7)    0.0025 (7)
  O2    0.0577 (11)   0.0566 (10)   0.0220 (8)    0.0189 (8)   0.0017 (7)    0.0056 (7)
  O3    0.0422 (10)   0.0517 (9)    0.0257 (8)    0.0121 (7)   −0.0042 (7)   0.0093 (7)
  O4    0.0478 (10)   0.0534 (10)   0.0251 (8)    0.0274 (8)   0.0074 (7)    0.0035 (7)
  N1    0.0326 (10)   0.0357 (9)    0.0231 (9)    0.0089 (7)   0.0018 (7)    0.0043 (7)
  C1    0.0377 (13)   0.0276 (10)   0.0255 (11)   0.0000 (9)   0.0033 (9)    0.0058 (8)
  C2    0.0325 (12)   0.0258 (9)    0.0229 (10)   0.0025 (8)   0.0059 (9)    0.0050 (8)
  C3    0.0319 (12)   0.0284 (10)   0.0246 (11)   0.0018 (8)   −0.0012 (9)   0.0081 (8)
  C4    0.0282 (11)   0.0322 (10)   0.0323 (12)   0.0097 (8)   0.0035 (9)    0.0086 (9)
  C5    0.0327 (12)   0.0271 (10)   0.0271 (11)   0.0052 (8)   0.0059 (9)    0.0062 (8)
  C6    0.0289 (11)   0.0242 (9)    0.0205 (10)   0.0036 (8)   0.0000 (8)    0.0038 (8)
  C7    0.0272 (11)   0.0251 (9)    0.0261 (11)   0.0037 (8)   0.0049 (8)    0.0047 (8)
  O5    0.0415 (9)    0.0386 (8)    0.0343 (8)    0.0153 (7)   0.0085 (7)    0.0085 (7)
  O6    0.0468 (10)   0.0400 (8)    0.0408 (9)    0.0073 (7)   0.0065 (8)    0.0045 (7)
  Cl1   0.0335 (3)    0.0385 (3)    0.0323 (3)    0.0111 (2)   0.0022 (2)    0.0086 (2)
  ----- ------------- ------------- ------------- ------------ ------------- ------------

Geometric parameters (Å, °) {#tablewrapgeomlong}
===========================

  ---------------- ------------- ---------------- -------------
  O1---C1          1.317 (2)     C2---C7          1.397 (3)
  O1---H1          0.8200        C2---C3          1.410 (3)
  O2---C1          1.225 (2)     C3---C4          1.390 (3)
  O3---C3          1.346 (2)     C4---C5          1.376 (3)
  O3---H3          0.8199        C4---H4          0.9300
  O4---C5          1.358 (2)     C5---C6          1.397 (3)
  O4---H4A         0.8200        C6---C7          1.365 (3)
  N1---C6          1.470 (2)     C7---H7          0.9300
  N1---H1A         0.8900        O5---H5A         0.8616
  N1---H1B         0.8900        O5---H5B         0.8517
  N1---H1C         0.8900        O6---H6A         0.8764
  C1---C2          1.467 (3)     O6---H6B         0.8647
                                                  
  C1---O1---H1     109.5         O3---C3---C2     123.24 (18)
  C3---O3---H3     109.5         C4---C3---C2     120.50 (18)
  C5---O4---H4A    109.5         C5---C4---C3     119.87 (18)
  C6---N1---H1A    109.5         C5---C4---H4     120.1
  C6---N1---H1B    109.5         C3---C4---H4     120.1
  H1A---N1---H1B   109.5         O4---C5---C4     124.58 (17)
  C6---N1---H1C    109.5         O4---C5---C6     115.57 (17)
  H1A---N1---H1C   109.5         C4---C5---C6     119.85 (18)
  H1B---N1---H1C   109.5         C7---C6---C5     120.75 (18)
  O2---C1---O1     122.79 (18)   C7---C6---N1     121.88 (16)
  O2---C1---C2     123.65 (19)   C5---C6---N1     117.31 (16)
  O1---C1---C2     113.56 (17)   C6---C7---C2     120.62 (17)
  C7---C2---C3     118.40 (17)   C6---C7---H7     119.7
  C7---C2---C1     120.94 (18)   C2---C7---H7     119.7
  C3---C2---C1     120.67 (18)   H5A---O5---H5B   104.7
  O3---C3---C4     116.25 (17)   H6A---O6---H6B   106.8
  ---------------- ------------- ---------------- -------------

Hydrogen-bond geometry (Å, °) {#tablewraphbondslong}
=============================

  -------------------- --------- --------- ------------- ---------------
  *D*---H···*A*        *D*---H   H···*A*   *D*···*A*     *D*---H···*A*
  O1---H1···O6         0.82      1.88      2.6945 (19)   171
  O3---H3···O2         0.82      1.96      2.672 (2)     145
  O4---H4A···Cl1^i^    0.82      2.21      3.0097 (15)   164
  N1---H1A···O6^ii^    0.89      2.02      2.903 (2)     169
  N1---H1B···O5^iii^   0.89      1.96      2.853 (2)     178
  N1---H1C···Cl1^iv^   0.89      2.35      3.1950 (18)   157
  O5---H5A···O2^v^     0.86      2.16      2.935 (2)     149
  O5---H5B···Cl1       0.85      2.41      3.1494 (15)   146
  O6---H6A···Cl1       0.88      2.27      3.1386 (16)   174
  O6---H6B···O5^vi^    0.86      1.99      2.850 (2)     173
  -------------------- --------- --------- ------------- ---------------

Symmetry codes: (i) −*x*, −*y*+1, −*z*+1; (ii) −*x*+1, −*y*, −*z*+1; (iii) *x*−1, *y*, *z*+1; (iv) −*x*+1, −*y*+1, −*z*+1; (v) *x*+1, *y*, *z*; (vi) −*x*+1, −*y*, −*z*.

###### Hydrogen-bond geometry (Å, °)

  *D*---H⋯*A*          *D*---H   H⋯*A*   *D*⋯*A*       *D*---H⋯*A*
  -------------------- --------- ------- ------------- -------------
  O1---H1⋯O6           0.82      1.88    2.6945 (19)   171
  O3---H3⋯O2           0.82      1.96    2.672 (2)     145
  O4---H4*A*⋯Cl1^i^    0.82      2.21    3.0097 (15)   164
  N1---H1*A*⋯O6^ii^    0.89      2.02    2.903 (2)     169
  N1---H1*B*⋯O5^iii^   0.89      1.96    2.853 (2)     178
  N1---H1*C*⋯Cl1^iv^   0.89      2.35    3.1950 (18)   157
  O5---H5*A*⋯O2^v^     0.86      2.16    2.935 (2)     149
  O5---H5*B*⋯Cl1       0.85      2.41    3.1494 (15)   146
  O6---H6*A*⋯Cl1       0.88      2.27    3.1386 (16)   174
  O6---H6*B*⋯O5^vi^    0.86      1.99    2.850 (2)     173

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .
