  Usually the ions in solid are in the positive oxidation states or in the
negative oxidation state depending upon the chemical environment. It is highly
unusual for an ion having both positive as well as negative oxidation state in
a particular compound. Structural analysis suggest that the alkaline earth
ammine borohydrides (AABH) with the chemical formula M (BH4)2(NH3)2 (M = Mg,
Ca, or Sr) where hydrogen is present in +1 and -1 oxidation states. In order to
understand the oxidation states of hydrogen and also the character of chemical
bond present in AABH we have made charge density, electron localization
function, Born effective charge, Bader effective charge, and density of states
analyses using result from the density functional calculations. Our detailed
analyses show that hydrogen is in amphoteric behavior with hydrogen closer to
boron is in negative oxidation state and that closer to nitrogen is in the
positive oxidation state. Due to the presence of finite covalent bonding
between the consitutents in AABH the oxidation state of hydrogen is
non-interger value. The confirmation of the presence of amphtoric behavior of
hydrogen in AABH has implication in hydrogen storage applications.
