α-Tetraphosphorus trichalcogenide diiodide compounds containing both sulfur and selenium

Abstract

Two isomers of each of α-P₄S₂SeI₂ and α-P₄SSe₂I₂ have been identified by ³¹P and ⁷⁷Se NMR spectroscopy in mixtures made by direct combination of the elements. The same compounds were formed as a result of a photochemical redistribution reaction between α-P₄S₃I₂ and α-P₄Se₃I₂ in solution in CS₂. Systematic changes in chemical shifts and in coupling constants with alterations in molecular geometry, as sulfur was replaced by selenium in the series α-P₄S₃I₂1–α-P₄S₂SeI₂2,3–α-P₄SSe₂I₂4,5–α-P₄Se₃I₂6, are reported.