SYNTHESIS AND CRYSTAL-STRUCTURE OF SNP2S6

We report the synthesis and single-crystal analysis of the first layer ed AP(2)S(6) compound. The structure of the title compound, SnP2S6, is rhombohedral, space group <R(3)over bar> with a = 5.999(2) Angstrom a nd c = 19.424(4) Angstrom and Z = 3. The diffraction data are refined to a final R value of 0.0158. This compound is an ordered defect struc ture of the Fe2P2S6 type where one-half of the metal sites are vacant. Hence, the tin atoms in SnP2S6 have a formal oxidation state of +4. T his compound has previously been shown by us to display nonlinear opti cal behavior.