K4In2(PSe5)2(P2Se6) and Rb3Sn(PSe5)(P2Se6): One-Dimensional Compounds with Mixed Selenophosphate Anions

Abstract

The reaction of In with a molten mixture of K2Se/P2Se5/Se yielded brick-red, needle-like crystals of K4In2(PSe5)2(P2Se6). The reaction of Sn with a molten mixture of Rb2Se/P2Se5/Se yielded black plate-like crystals of Rb3Sn(PSe5)(P2Se6). Both compounds are stable in air and water. K4In2(PSe5)2(P2Se6) crystallizes in the monoclinic space groupCc(9) witha=11.1564(1) Å,b=22.8771(1) Å,c=12.6525(2) Å,β=109.039(1)°,Z=4, andR/Rw=4.1/4.4%. The one-dimensional structure features [In2(PSe5)2(P2Se6)]4n−nchains that consist of In2(PSe5)2dimers. These dimers are then bridged along thea-axis by tetradentate [P2Se6]4−units to form the chain. In3+is in an octahedral environment. Rb3Sn(PSe5)(P2Se6) crystallizes in the monoclinic space groupP21/a(14) witha=14.013(2) Å,b=7.3436(8) Å,c=21.983(4) Å,β=106.61(1)°,Z=4, andR/Rw= 3.5/4.4%. The one-dimensional structure features [Sn(PSe5)(P2Se6)]3n−nchains with octahedral Sn4+. The neighboring Sn atoms are connected via tetradentate [P2Se6]4−units to form the chain. The [PSe5]3−act as chelating side groups employing the diselenide “arm” and one of the monoselenide atoms to coordinate to Sn. The compounds were characterized with differential thermal analysis, far-IR, and solid-state UV/vis diffuse reflectance spectroscopy.