EFFECTS OF PROTONATION IN DECAVANADATES - CRYSTAL-STRUCTURE OF TETRAKIS(N-HEXYLAMMONIUM) DIHYDROGENDECAVANADATE(V)

The crystal structure of a new dihydrogendecavanadate(V) of n-hexylamm onium has been determined by means of X-ray diffraction data. Empirica l bond length/bond number calculations have located the protonation si tes in two triply-linked oxygen atoms which reinforce theoretical resu lts of relative basicities of the oxygen sites in decavanadate anions. The crystal structure is stabilised by electrostatic forces and an ex tensive network of hydrogen contacts among anions and cations. The dih ydrogendecavanadate(V) anions are located on the (001) plane and are j oined via hydrogen bonding. d(O ... O) = 2.63 and 2.64 Angstrom, givin g evidence of strong O ... O interactions. Infrared spectroscopy and t hermoanalytical methods have been applied in order to confirm structur al properties.