The structures in solution of certain ring compounds of phosphorus and sulphur

Abstract

Studies on the vibrational spectra of solutions of cyclic phosphorus and sulphur compounds with bridging N, NH, and O have been used to deduce the structures of the rings. In aqueous solution the (PO₂NH)₃^3– and P₃O₉^3– anions have D_3h symmetry, and (PO₂NH)₄^4– has D_2d; in organic solvents, (PNCl₂)₃ has D_3h, (PNCl₂)₄ and S₄N₄- have D_2d, and S₄(NH)₄ has C_4v symmetry. It appears likely from the spectra of the solid ammonium and potassium tetraphosphoroimidate that the rings in these have approximate C_2h symmetry.