CRYSTAL AND MOLECULAR-STRUCTURE OF 1,5'-BIDECABORAN(14)YL - NEW BORANE FROM GAMMA-IRRADIATION OF DECABORANE(14)

The previously unknown structure of the most abundant of several isomers B20H26 produced by irradiation of decaborane(14) has been determined by X-ray crystal-structure analysis. The molecule, named l, 5-bidecaboran(14)yl, is made up of a l-decaboran(14)yl group linked by a two-center B-B bond to a 5-decaboran(14)yl group. The linking Bl-B5 bond, a type for which no previous precise metrical data exist, has a length of 1.698 (3) A. The interatomic distances and angles in the decaboranyl groups, after correction for the effects of thermal motion, agree remarkably well with the corresponding ones in decaborane(14) known from analysis oflow-temperature neutron-diffraction data. Most of the larger differences are for distances and angles involving atoms B1 and B5 of the connecting link. Crystallographic data: monoclinic, space group P2n, a = 7.235 (1) k, b= 15.453(4) A, c = 14.895 (3) A, 3 = 91.42 (2), 4 formula units per cell, dcM = 0.967 g/cm3 [X(CuKa) 1.5418 A]. © 1979, American Chemical Society. All rights reserved.