Polynuclear chloromercurate(II) systems in their chloropyridinium salts

The chloromercurate(II) salts of 2-, 3- and 4-chloropyridine display a vari ety of anion stoichiometries and structures, including the rare [[Hg3Cl10]( 4-) stoichiometry. 2-Chloropyridinium trichloromercurate(II), (I), (C5H5ClN )[HgCl3], monoclinic, P2(1)/n, a = 9.094(8), b = 18.143 (4), c = 12.902 (3) Angstrom, beta = 106.13 (4)degrees with Z = 8, has the [HgCl3](-) stoichio metry, but the anions are infinite chains composed of [HgCl3](-), HgCl2 and Cl- moieties linked by longer Hg ... Cl contacts. Hydrogen bonds link the cations to the formal Cl- ions. Tetrakis- (3-chloropyridinium) decachlorotr imercurate(II), (II), (C5H5ClN)(4)[Hg3Cl10], monoclinic, P2(1)/n, a = 7.522 (2), b = 28.046 (3), c = 9.165 (2) Angstrom, beta = 105.78 (2)degrees with Z = 2, has the rare [Hg3Cl10](4-) stoichiometry and contains infinite one- dimensional double-stranded {([HgCl4](2-))(2) [HgCl2]}(n) anionic chains ma de up of linear HgCl2 and distorted [HgCl4](2-) entities Linked together by longer Hg ... Cl contacts. The HgCl2 moieties are joined by double [HgCl4] (2-) bridges. Hydrogen bonds link the cations to the sides of the anionic c olumns. Tetrakis(4-chloropyridinium) decachlorotrimercurate(II), (III), (C5 H5ClN)(4)[Hg3Cl10], triclinic, P (1) over bar, a = 9.907(3), b = 13.226 (2) , c = 7.282 (2) Angstrom, alpha = 84.41 (2), beta = 74.81 (2), gamma = 87.3 4(2)degrees with Z = 1, also has the [Hg3Cl10](4-) stoichiometry and the sa me type of {([HgCl4](2-))(2) [HgCl2]}(n) anionic chains that were found in compound (II), but the formal HgCl2 and [HgCl4](2-) moieties are. more disc rete with much weaker contacts linking the individual units. Bifurcated hyd rogen bonds with the cations cross-link the anionic chains to form an infin ite two-dimensional network. Second forms of the 3- and 4-chloropyridinium salts were also obtained. 3-Chloropyridinium trichloromercurate(II), (IV), (C5H5ClN)-[HgCl3], monoclinic, P2(1)/c, a = 7.243(5), b = 22.145 (8), c = 1 2.320 (3) Angstrom, beta = 99.52 (4)degrees with Z = 8, has the [HgCl3](-) stoichiometry, but the anions are infinite chains composed of distorted [Hg 2Cl6](2-) moieties, Bifurcated. hydrogen bonds from the cations cross-link the anionic chains to form infinite two-dimensional layers. Bis(4-chloropyr idinium) hexachlorodimercurate(II), (V), (C5H5ClN)(2)[Hg2Cl6], monoclinic, C2/m, a = 13.447(3), b = 7.534(2), c = 9.939 (2) a, beta = 97,48 (2)degrees with Z = 2, contains highly symmetrical discrete [Hg2Cl6](2-) anions, Bifu rcated hydrogen bonds from the cations interconnect the anions to form infi nite one-dimensional chains.