Structural investigations of metal nitrate complexes. Part III. Crystal and molecular structures of two crystalline forms of dinitratobis(α-picoline)copper(II)

Abstract
The structures of two crystalline forms of the title compound have been determined by single-crystal X-ray analyses. The crystals of both forms are monoclinic, space group P21/c, with Z= 4 in unit cells of dimensions a= 8·31, b= 14·81, c= 14·14 Å, β= 123·9°[Form (I)] and a= 8·57, b= 14·39, c= 14·20 Å, β= 119·5°[Form (II)]. Both structures were solved by conventional Patterson and Fourier methods from 1134 [Form (I)] and 1341 [Form (II)] observed data and refined by block-diagonal least-squares calculations to R 0·12 [Form (I)] and 0·09 [Form(II)]. Although both forms of the complexes possess grossly similar monomeric molecular structures, there are detailed differences in molecular geometry which may arise from the different packing within the two types of crystals.