CRYSTAL-STRUCTURE OF CALCIUM BIS[(2-HYDROXYETHYL)IMINODIACETATO]COBALTATE(III) TETRAHYDRATE

The X-ray crystal structure of Ca[Co(Heida)(2)](2). 4H(2)O, where Heid a(2-) is the N-(2hydroxyethyl)iminodiacetate ion, is determined (MoKal pha radiation, graphite monochromator, omega scan mode, R = 0.034). Th e crystals are triclinic; a = 6.795(1), b = 8.916(2), and c = 15.451(3 ) Angstrom; alpha = 75.13(3)degrees, beta = 81.76(3)degrees, and gamma = 82.22(3)degrees; sp. gr. P (1) over bar; and Z = 1. The structure i s composed of anionic complexes [Co(1)(Heida)(2)](-), cationic layers {[Ca(H2O)(2)Co(2)(Heida)(2)]}(infinity)(+), and crystallization water molecules. Two symmetry-independent cobalt atoms have coordination pol yhedra in the shape of an octahedron formed by two N atoms and four ca rboxylate O atoms of the Heida(2-) ligands. The hydroxyethyl groups do not coordinate the Co atoms. The Heida(2-) ligands are tridentate in the Co(1) complexes and pentadentate in the Co(2) comrlexes due to two additional bonds with the Ca atoms. The Ca atoms are coordinated by f our O atoms of the ligands and two water molecules, The structural for mula of the compound is [Co(Heida)(2)][Ca(H2O)(2)Co(Heida)(2)]. 2H(2)O .