Crystallographic disorder in mixed-valent dioxo-bridged Mn-III,Mn-IV complexes. [Mn2O2(bpb)(4)]-[Ce(NO3)(6)].5H(2)O

The structure of tetrakis(2,2'-bipyridine)di-mu-oxo-di-manganese(3+) hexani tratocerate(3-) pentahydrate, [Mn2O2(bpy)(4)][Ce(NO3)(6)].5H(2)O, is descri bed; M-r = 1368.88, monoclinic, C2/c, a = 12.940 (3), b = 18.060 (2), c = 2 2.54 (1) Angstrom, beta = 96.29(2)degrees, V = 5237 (3) Angstrom(3), T = 13 2 K, Z = 4, F(000) = 2752, D-x = 1.736 Mg m(-3), lambda(Mo K alpha) = 0.710 73 Angstrom, mu = 1.429 mm(-1), R(F-2) = 0.0358, wR(F-2) = 0.0783 for 4877 reflections with I > 2 sigma(I). The cation does not have crystallographica lly distinguishable Mn atoms. An analysis of the atomic displacement ellips oids and Mn-N bond distortions has been used to develop a model for the dis order in this type of mixed-valent complex. The anion, Ce(NO3)(6)(3-), has a distorted icosahedral geometry.