HYDROTHERMAL SYNTHESIS AND CRYSTAL-STRUCTURE OF [(CH3NH3)(1.03)K-2.97]SB12S20-CENTER-DOT-1.34H(2)O

A novel thioantimonate(III) [(CH3NH3)(1.03)K-2.97]Sb12S20. 1.34H(2)O w as synthesized hydrothermally. It crystallizes in space group P (1) ov er bar, with a = 11.9939(7) Angstrom, b = 12.8790(8) Angstrom, c = 14. 9695(9) Angstrom, alpha = 100.033(1)degrees, beta = 99.691(1)degrees, gamma = 108.582(1)degrees, V = 2095.3(2) Angstrom(3), and Z = 2. The s tructure is determined from single crystal X-ray diffraction data coll ected at room temperature and refined to R(F) = 0.037. In the crystal structure, each Sb(III) atoms has short bonds (2.37-2.58 Angstrom) to three S atoms. The pyramidal [SbS3] groups share common S atoms formin g two types of centrosymmetric [Sb12S20] rings with the same topology. These rings are interconnected by weaker Sb-S bonds (2.92-3.29 Angstr om) into 2-dimensional layers. Adjacent layers are parallel with K+ an d CH3NH3+ ions and H2O molecules located between them. Variation of bo nd valence sums calculated for the Sb(III) cations is found to be corr elated with the coordination geometry. This is interpreted as due to t he stereochemical activity of their lone electron pairs. (C) 1998 Acad emic Press.