The Crystal and Molecular Structure of Dinitrato(triphenylphosphine)mercury(II)

The structure of dinitrato(triphenylphosphine)mercury(II), Hg(N03)2.P(C6H5)3, has been determined from single–crystal X-ray data measured on a computer–controlled diffractometer. The crystals are monoclinic, have a unit cell of dimensions a = 10.39(1), b = 9.56(1), c = 19.44(2) A, β = 94.3(1)°, which contains 4 molecules, and they belong to the space group, P21/c. The structure has been refined by least–squares methods from 2470 independent observed reflections to a conventional R-factor of 0.061. The Hg atom has a distorted tetrahedral coordination with Hg—O bond lengths of 2.190(8), 2.428(8), and 2.560(9) A and an Hg—P bond distance of 2.359(3) A. There are 2 distinct types of NO3 groups bonded to Hg. One is an unshared, unidentate ligand and the other acts as a bridging group joining 2 Hg atoms. Chains of—Hg—NO3—Hg—atoms are formed which follow crystallographic two-fold screw axes in the b-direction.