The Syntheses and the X-Ray Crystal Structure of Tetramethylammonium Tetrakis- and Tris(thiocyanato)cadmates(II), [(CH3)4N]2[Cd(SCN)4] and [(CH3)4N][Cd(SCN)3

Abstract

Abstract The crystal and molecular structure of the two new thiocyanatocadmate(II) complexes indicated in the title were determined by the single-crystal X-ray-diffraction technique. [(CH3)4N]2[Cd(SCN)4] is tri-clinic, with a space group of P\bar1; a=7.300(2), b=13.019(4), c=5.8920(9) Å, α=96.32(2), β=93.080(18), γ=104.63(2)°, and Z=1, while [(CH3)4N][Cd(SCN)3] is orthorhombic with a space group of Pna21; a=10.506(3), b=13.797(5), c=9.4506(18) Å, Z=4. In both complexes, the cadmium atom is in an octahedral geometry. In 1, the metal atom is at the center of symmetry, and respective pairs of side-by-side metal atoms are bridged by two thiocyanate (SCN) ions, where one SCN ion is S-coordinated and the other is N-coordinated to the same-side metal atom. Also bonded with two nitrogen atoms of unidentate SCN ions, the metal atom is 4N2S-hexa-coordinated, and they line up along the c-axis in a polymeric form. In 2, respective pairs of side-by-side metal atoms are bridged by three SCN ions, two of those SCN ions being S-coordinated, and one N-coordinated, to the same-side metal atom; each metal atom is 3S3N-hexa-coordinated, and the chain of the polymeric complex lines up along the a-axis. The tetramethylammonium ions bond with the polymeric complex only by the ionic bonding. The final R values obtained are 1=0.039 and 2=0.050.