تغییر سلول واحد در سری اکتاکیس(دی متیل سولفوکسید) لانتانیدIII) یدید

The octakis(dimethyl sulfoxide) neodymium(III), gadolinium(III), erbium(III) and lutetium(III) iodides crystallize in the monoclinic space group P21/n (No. 14), with Z= 4, while the corresponding solvates of the larger lanthanum(III), cerium(III) and praseodymium(III) ions crystallize in the orthorhombic space group Pbca (No. 61), Z= 8. All the lanthanoid(III) ions coordinate eight oxygen atoms from dimethyl sulfoxide ligands in a distorted square antiprismatic configuration with mean M-Obond distances of 2.30, 2.34, 2.38 to 2.43 Å (M = Lu, Er, Gd, Nd) for the monoclinic [M((CH3)2SO)8]I3 structures, and from 2.44, 2.47 to 2.49 Å (M = Pr, Ce and La) for the orthorhombic structures, respectively. Some of the dimethyl sulfoxide ligandswere appeared in two alternative configurations related by a twist around the metaloxygen (M-O) bond and were refined as disordered model. Despite longer bonddistances and larger M-O-S angles the cell volumes are smaller for the orthorombic structures than for the monoclinic structure, showing a more efficient packing arrangement.