CRYSTAL STRUCTURE OF CS2(B9C2H11)CO(B8C2H10)CO(B9C2H11).H2O, A SALT OF A 3-ICOSAHEDRAL-FRAGMENT METALLOCARBORANE

The crystal structure of the monohydrated cesium salt of the bis[π-(3)-1,2-dicarbollylcobalt]-π-(3,6)-1,2-dicarbacanastide ion, Cs2Co2B26C6H32·H2O, has been determined from 3649 independent X-ray data obtained from a single crystal by counter methods. The crystals are monoclinic, space group P21/c. Four molecules are in the unit cell with a = 7.089 (4) Å, b = 19.240 (14) Å, c = 20.682 (4) Å, and β = 98.00 (6)°. The calculated density is 1.871 g/cm3. The structure was refined by least squares to a conventional R factor of 3.4%. The carborane anion, (B9C2H11)Co(B8C2H10)Co(B9C2H11)2-, consists of three linked icosahedra. Two corners of a central 10-light-atom icosahedron are occupied by cobalts each of which is common to another icosahedron containing 11 light atoms. Five of the positions in the icosahedra are occupied by carbons but, because of disorder, two positions contain half-boron-half-carbon atoms. The cages are staggered across the cobalts and all carbons are as close to each other as is possible in this configuration. All hydrogens except those in the water molecule were located. © 1969, American Chemical Society. All rights reserved.