Crystal structures of ammonium and cesium pentadecafluorotetraantimonates(III)

Antimony(III) fluoride complexes with compositions (NH4)(3)Sb4F15 (I) and C s3Sb4F15 (II) are structurally characterized. Crystals I are triclinic: a = 8.317(3) Angstrom, b = 10.419(6) Angstrom, c = 10.826(3) Angstrom, alpha = 63.71(4)degrees, beta = 73.24(3)degrees, gamma = 77.42(5)degrees, Z = 2, r ho (calcd) = 3.42 g/cm(3), rho (exp) = 3.45 g/cm(3), space group P (1) over bar, R = 0.051; crystals II are monoclinic: a = 8.079(2) Angstrom, b = 29. 116(8) Angstrom, c = 8.162(2) Angstrom, beta = 117.08(2)degrees, Z = 4, rho (calcd) = 4.549 g/cm(3), rho (exp) = 4.50 g/cm(3), space group P2(1)/c, R = 0.036. Structure I is composed of SbF4E and SbF5E polyhedra combined into tetranuclear chains; crystals II consist of SbF4E polyhedra, two of which form a dimer Sb2F7E2, while the other two are isolated (E is the antimony l one electron pair).