Synthesis, Crystal Structure, and Properties of Chromium(III) Trimetaphosphinate Heptahydrate, Cr(PO₂NH)₃×7H₂O.

Abstract

Chromium I 5500 Synthesis, Crystal Structure, and Properties of Chromium(III) Trimetaphosphinate Heptahydrate, Cr(PO2NH)3·7H2O. -The title compound precipitates from an aqueous solution of Cr(NO3)3 and Na3(PO2NH)3. The growth of single crystals by a gelatine diffusion technique is described. Cr(PO2NH)3·7H2O crystallizes in the monoclinic space group P21/n with Z = 4. The P3N3 rings of the [(PO2NH)3] 3ions are present as mixture of boat and twist conformations in the ratio 1:1. The Cr 3+ ions are octahedrally coordinated by six water molecules. The arrangement of the [Cr(OH2)6] 3+ octahedra and the [(PO2NH)3] 3units can be described as a distorted variant of the CsCl structure type.