Metal-selenium interactions. Crystal structure of binuclear [((1)eta-iodo)-((2)eta-mu-iodo) (triphenyl selenophosphorane-Se)mercury(II)](2) complex

Reaction of mercury(II) diiodide with triphenyl selenophosphorane-Se (1:1 m ole ratio) in acetone followed by recrystallisation of the product from chl oroform formed crystals of stoichiometry {HgI2(Ph3PSe)}(1). Compound 1 exis ts as a centrosymmetric homobimetallic dimer, {Hg(mu -I)I(Ph3PSe)}(2), as m onoclinic crystals of space group P2(1)/n. The dimer comprises two mu (2)-i odo atoms that form unequal Hg-I bonds {2.8230(10), 3.1135(9) Angstrom} and two equal terminal Hg-I bonds {2.6524(10) Angstrom}. The Se atom of Ph3PSe forms terminal Hg-Se bond {2.5914(11) Angstrom} and thus the geometry abou t each Hg centre is distorted tetrahedral and the range of tetrahedral bond angles is 92.97(2) to 130.85(3)(0), the largest being that of Se(l)-Hg(l)- I(1) and the shortest, I(2)-Hg(l)-I(2)*. Hg-Hg and I-I separations of {4.09 30(11) Angstrom} and {4.3097(15) Angstrom} are more than the sums of their respective van der Waal radii {3.00 Angstrom and 4.24 Angstrom}.