STRUCTURE OF BIS(TETRAETHYLAMMONIUM) HEXAIODODIMERCURATE(II) DIIODOMERCURY(II)

[N(C2H5)4]2[Hg2I6].HgI2, M(r) = 1781.53, tetragonal, P4(2)/m, a = 10.391 (1), c = 17.051 (1) angstrom, V = 1841.4 angstrom 3, Z = 2, D(x) = 3.386 g cm-3, lambda(Mo K-alpha) = 0.71073 angstrom, mu = 195.23 cm-1, F(000) = 1628, T = 293 K, R = 0.0468 for 1201 observed reflections. The structure consists of two crystallographically independent tetraethylammonium cations, a linear centrosymmetric HgI2 molecule [Hg-I bond length is 2.574 (1) angstrom] and a dimeric anion [Hg2I6]2-. There are two van der Waals contacts between the Hg atom of HgI2 and two iodines from [Hg2I6]2- [3.547 (2) angstrom] and two I-I van der Waals contacts [3.769 (2) angstrom] between iodines of HgI2 and [Hg2I6]2-. The latter are considerably shorter than the van der Waals I...I distance (4.3 angstrom).