X–ray Single Crystal Structure and Raman Spectrum of Ammonium Hexafluoroarsenate

Abstract

AbstractThe structure of ammonium hexafluoroarsenate, NH4AsF6, has been determined by X‐ray diffraction using a single crystal grown from saturated solution in anhydrous HF. NH4AsF6 crystallizes rhombohedral with the KOsF6 structure type, with a = 7.459(3) Å, c = 7.543(3) Å (at 200 K), Z = 3, space group $R{\bar 3}$ (No. 148). No phase transition was observed in the 100 K–296 K temperature range. The structure is dominated by regular AsF6 octahedra and disordered NH4+ cations. Raman spectrum of a single crystal of NH4AsF6 shows the bands at 372 cm−1, 572 cm−1, 687 cm−1 (AsF6−) and at 3240 cm−1 and 3360 cm−1 (NH4+).