Structure of tetraaquacopper(II) chlorate at 296 and 223 K.

Cu(H2O)42, Mr = 302.51, orthorhombic, Pbca, lambda (Mo K alpha) = 0.71069 A, Z = 4, F(000) = 604; T = 296 K, a = 12.924 (3), b = 9.502 (2), c = 7.233 (1) A, V = 888.3 (3) A3, D chi = 2.26 g cm-3, mu = 31.04 cm-1, R = 0.041 for 1174 unique reflections with I greater than sigma (I); T = 223 K, a = 12.853 (2), b = 9.492 (2), c = 7.216 (2) A, V = 880.4 (3) A3, D chi = 2.28 g cm-3, mu = 31.28 cm-1, R = 0.033 for 1279 unique reflections with I greater than sigma (I). The single type of copper ion is octahedrally coordinated by four water oxygens and two chlorate ion oxygens; the complex is characterized by three distinct pairs of Cu-O distances (which we have previously described as '2 + 2 + 2' coordination), one of which is substantially larger than the remaining two. The nominal 90 degrees O-Cu-O angles of the complex differ from that value by at most +/- 1.8 degrees. The observed structure of the complex is typical for copper(II) and is consistent with the Jahn-Teller effect. The single type of chlorate ion shows the expected trigonal pyramidal geometry, with average Cl-O bond lengths 1.485 (13) and 1.490 (11) A and average O-Cl-O bond angles 106.8 (13) and 106.8 (13) degrees for 296 and 223 K, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)