Crystal structures and normal coordinate analyses of trans-(n-Bu4N)(2) [ReCl4IX], X = NCS, NCSe

The crystal structures of trans-(n-Bu4N)(2)[ReCl4I(NCS)] (triclinic, space group <P(1)over bar>, a = 11.268(3), b = 11.696(2), c = 18.109(3) Angstrom, alpha = 98.68(2) beta = 106.40(2), gamma = 97.58(2)degrees, Z = 2) and tra ns-(n-Bu4N)(2)[ReCl4I(NCSe)] (orthorhombic, space group P 2(1)2(1)2(1), a = 11.839(2), b = 12.2679(10), c = 31.136(5) Angstrom, Z = 4) have been deter mined by single crystal X-ray diffraction analysis. Based on the molecular parameters of the X-ray determinations the low temperature (10 K) IR and Ra man spectra of the (n-Bu4N) salts have been assigned by normal coordinate a nalysis. The valence force constants are f(d)(ReN) = 1.69(NCS) and 1.65(NCS e) mdyn/Angstrom.