Crystal structure of K[Hg(SCN)(3)] – a redetermination

The crystal structure of the room-temperature modification of K[Hg(SCN)(3)], potassium tri­thio­cyanato­mercurate(II), was redetermined based on modern CCD data. In comparison with the previous report [Zhdanov & Sanadze (1952 ▶). Zh. Fiz. Khim. 26, 469–478], reliability factors, standard deviations of lattice parameters and atomic coordinates, as well as anisotropic displacement parameters, were revealed for all atoms. The higher precision and accuracy of the model is, for example, reflected by the Hg—S bond lengths of 2.3954 (11), 2.4481 (8) and 2.7653 (6) Å in comparison with values of 2.24, 2.43 and 2.77 Å. All atoms in the crystal structure are located on mirror planes. The Hg(2+) cation is surrounded by four S atoms in a seesaw shape [S—Hg—S angles range from 94.65 (2) to 154.06 (3)°]. The HgS(4) polyhedra share a common S atom, building up chains extending parallel to [010]. All S atoms of the resulting (1) (∞)[HgS(2/1)S(2/2)] chains are also part of SCN(−) anions that link these chains with the K(+) cations into a three-dimensional network. The K—N bond lengths of the distorted KN(7) polyhedra lie between 2.926 (2) and 3.051 (3) Å.