CRYSTAL AND MOLECULAR-STRUCTURES OF AMMONIUM AND DIMETHYLAMMONIUM PHENYLPENTACHLOROANTIMONATES NH4[PHSBCL5] AND (CH3)2NH2[PHSBCL5] AND AMMONIUM PHENYLPENTABROMOANTIMONATE NH4[PHSBR6]

The anionic Sb(V) complex compounds NH4[PhSbCl5] (I), NH4[PhSbBr5] (II), and (CH3)2NH2[PhSbCl5] (III) are synthesized and their x-ray structures are studied in continuation of a study of the mutual effect of ligands (MEL) in complexes of representative elements. All compounds crystallize in the orthorhombic system: (I) Pmn2(1), a = 7.118(1), b = 12.550(2), c = 7.154(1) angstrom, Z = 2, R = 0.029; (II) Pmn2(1), a = 7.431(4), b = 13.042(2), c = 7.432(3) angstrom, Z = 2, R = 0.044; (III) Pmna a = 27.442(5), b = 7.331(1), c = 7.295(2) angstrom, Z = 4, R = 0.033. The [PhSbX5] complexes are octahedral with central Sb atoms. The bond lengths are Sb-Cl = 2.402(2)-2.432(1) angstrom (I); 2405(3)-2.429(4) angstrom (III); and Sb-Br = 2.548(5)-2.608(5) angstrom (II). The Sb-X bonds (X = Cl and Br) are lengthened in comparision to those in [SbX6]. The greatest lengthening is seen in the position trans to the phenyl. Crystal packing effects on the structure of [PhSbX5] are discussed.