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Abstract

The phosphites M₂(HPO₃)₃ . 7H₂O (M = V, Cr), MH₃P₂O₆ . 3 H₂O (M = V, Mn) and H₃[Cr(HPO₃)₃ . 10 H₂O were studied in the solid phase by means of the thermography, magnetochemistry, and spectroscopy (IR, EPR, electronic reflection) techniques. The EPR spectrum of V₂(HPO₃)₃ . 7H₂O at ambient temperature displays hyperfine splitting arising from the nucleus ⁵¹V. In the phosphites H₃[Cr(HPO₃)₃] . 10H₂O, MnH₃P₂O₆ . 3H₂O, and probably also VH₃P₂O₆ . 3H₂O, in contrast to the other hithero studied hydrogenphosphites, coordination of the HPO^2-₃ anions occurs. These anions from which the molecules of the crystal water hydrogen bonds of the energy 40kJ mol^-1. The Jorgensen's parameters of the ligand in the tris(phosphito)chromate(III) anion are f = 0.95 and h = 1.50.