Vol. 8, No. 12, December 1969
I.L-~ARBONYL-BIS-I.L-DIPHENYLGERMANIUM-BI~(TRICARBONYLIRON) 2703
bonding. When compared with distances of -2.6 and -2.5 A for single and double bonds, i t suggests the presence of a triple or quadruple bond. The rotational configuration of the MozCls4- ion is again found to be eclipsed (crystallographic symmetry Ci; virtual symmetry Ddh), which requires the presence of a significant 6 component in the Mo-Mo bond and thus shows t h a t this bond is quadruple. In this compound the Mo2Cls4-ion has a very regular square parallelepiped structure, which comes very close to containing a cubic array of eight C1 atoms. The bases of the parallelepiped formed by the sets of C1 atoms bound t o each of the Mo atoms are square within the chemical significance of the data. The edges all lie within the range 3.332-3.367 if and the Cl-Cl-Cl angles run from 89.4 t o 90.4'. The vertical edges of the parallelepipid are 3.41 f 0.01 if. These vertical
edges are longer than the eight basal edges by 0.06 if. an amount which is highly significant statistically and undoubtedly this difference is real. Still, the difference is small both relatively (
