Crystal Structure of Calcium [Aqua(Nitrilotriacetatocobaltate(II)] Tetrahydrate, Ca[Co(Nta)(H2O)]2· 4H2O

Abstract

Crystals of Ca[CoII(Nta)]2· 6H2O (I), where Nta3–is a nitrilotriacetate ion, were synthesized and studied using X-ray diffraction analysis. They were found to be monoclinic: a= 6.991(1), b= 10.031(1), c= 16.238(3) A, β = 98.50(1)°, V= 1126.2(3) A3, space group P21/n, Z= 2, R1= 0.0241, wR2= 0.0636, GOOF = 1.050 (for 3132 reflections with I> 2σ(I)). Structure Iis composed of {[Co(Nta)(H2O)]–}1∞anion chains united by Ca2+cations into a three-dimensional framework. The coordination polyhedra of Co and Ca atoms are distorted octahedra. The Co(II) atom environment includes atoms N(1), O(1), O(3), and O(5) of one Nta3–ligand, a carbonyl O(2)" atom of the neighboring anion fragment, and an O(w1) atom of the water molecule. The shortest bond is formed by the Co atom with the bridging O(2)" atom in trans-position relative to atom N(1). The Co–O(2)" distance (2.029 A) is noticeably shorter than the other bond lengths, Co–O(Nta) (2.069–2.103 A), Co–O(w1), and Co–N(1) (2.155 and 2.177 A, respectively). Cations Ca2+are located in the inversion centers and involve in their coordination atoms O(4), O(6), O(w2), and the oxygen atoms symmetrically bond to them and arranged at 2.271(1), 2.420(1), and 2.351(2) A, respectively. The structural formula of the title compound is {Ca(H2O)2[Co(Nta)(H2O)]2}3∞· 2H2O.