Crystal and molecular structure of bis[dicarbonyl(triethylphosphine)-nitrosylferrio]mercury

Abstract

The crystal structure of the title compound has been determined by X-ray diffraction methods using absorption corrected counter data. Refinement, R 0·060 (for 1800 unique reflections), was carried out by a full-matrix least-squares procedure. The monoclinic unit cell, space group P2₁/n, has dimensions a= 7·257, b= 14·178, c= 12·533 Å, β= 94° 13′ for Z= 2. The crystal is disordered in that the nitrosyl groups could not be distinguished from the carbonyl groups. The two sets of radial ‘carbonyl’ groups adopt a staggered configuration as do each set of ethyl groups with respect to its set of ‘carbonyl’ groups. The space group imposes a centre of symmetry at the mercury atom but the molecule as a whole approximates to (S₆) symmetry. The mercury–iron distance is 2·534(2)Å.