Stereochemistry of Discrete Eight-Coordination. Iv. The Structure of the Bis(Nitrilotriacetato)Zirconate(IV) Ion in Crystals of the Potassium Salt

摘要

A quantitative description of the bis(nitrilotriacetato)zirconate(IV) ion, Zr(N(CH2COO)3)2(2-) (written as ZrA2(2-), comes from a three-dimensional X-ray analysis of crystalline structure for the potassium salt, K2ZrA2.H2O. The orthorhombic unit cell containing 4K2ZrA2.H2O has a = 14.84, b = 14.83, and c = 8.67A; the space group is Ccc2-C(2v)13. The coordination group is unmistakably dodecahedral with two nitrogen and two oxygen atoms at A vertices, and four oxygen atoms at B vertices. The observed stereoisomeric form of the complex anion appears to handle the problems of ring structure and nonbonding repulsions in a superior manner, better, indeed, than any competing form whether this be based upon the dodecahedron, the antiprism, or the cube. (Author)