Studies on Tetramethylammonium Selenate(VI) and Chromate(VI)

Abstract

Abstract [N(CH3)4]2SeO4 and [N(CH3)4]2CrO4 have been investigated by Infrared and Raman spectroscopy, coupled thermogravimetric and differential thermal analysis combined with mass spectroscopy of the evolved gases and temperature dependent X-ray diffraction. The crystal structure of [N(CH3)4]2SeO4 has been determined from single crystal data (cubic, Fm3̄m. a -11.1077(7) Å, Z = 4) and reveals [N(CH3)4]+ cations and SeO4 2- anions to be arranged in a Li2O -type of structure. While the cation framework of regular tetrahedra is orientationally fixed, the selenate anions are disordered. Powder diffraction data show [N(CH3)4]2CrO4 to be isostructural (cubic, Fm3̄m, a = 11,039(1) Å, Z = 4).