Compounds containing layers of composition [(Sb IIIF) XO 4] ( X = P, As). Crystal structures of Na(SbF)PO 4 · 1.5H 2O, Na(SbF)AsO 4, NH 4(SbF)PO 4 · H 2O, and NH 4(SbF)AsO 4 · 3H 2O

Abstract

The title compounds have been prepared in water by reaction of SbF 3 with dihydrogen phosphates or arsenates and characterized by single crystal X-ray work, IR, Raman, and Mössbauer spectroscopy. They have identical layer structures. Layers of composition [(SbF) XO 4] − ( X = P, As) were formed by sharing four corners between XO 4 tetrahedra and SbFO 4 pseudooctahedra. The lengths of the terminal SbF bond (with the lone pair in a trans-position) and the SbO bonds are 192 and 219 pm, respectively. The stacking of the layers and the interlayer distance depend on the cations and the number of intercalated water molecules. In Na(SbF)AsO 4 the Na + ion is coordinated by only two oxygen atoms within 300 pm. Crystal data: Na(SbF)PO 4 · 5H 2O, monoclinic, P2 1 m , a = 656.2(5), b = 654.1(5), c = 867.9(3) pm , β = 92.43(1)°, 889 reflections, 81 parameters, R = 0.044, R w = 0.046. NH 4(SbF)PO 4 · H 2O, tetragonal, I4 m , a = 656.6(3), c = 1439.8(5) pm , 680 reflections, 31 parameters, R = 0.023, R w = 0.021. Na(SbF)AsO 4, tetragonal, P4 ncc , a = 671.8(1), c = 1756.4(4) pm , 1056 reflections, 28 parameters, R = 0.052, R w = 0.065. NH 4(SbF)AsO 4 · 3H 2O, tetragonal, P4 ncc , a = 683.8(2), c = 1873.0(7) pm , 1194 reflections, 30 parameters, R = 0.042, R w = 0.050.