Crystal structure of Tutton’s salts Tl2[MII(H2O)6](SeO4)2, MII=Mg, Mn, Co, Ni, Cu, Zn

H12MgO14Se2Tl2, monoclinic, P121/a1 (no. 14), a = 9.434(2) Å, b = 12.634(2) Å, c = 6.292(1) Å, / = 105.72(2)°, V = 721.9 Å, Z = 2, Rgt(F) = 0.028, wRref(F ) = 0.047, T = 295 K. H12MnO14Se2Tl2, monoclinic, P121/a1 (no. 14), a = 9.490(1) Å, b = 12.734(2) Å, c = 6.332(1) Å, / = 105.57(1)°, V = 737.1 Å, Z = 2, Rgt(F) = 0.032, wRref(F ) = 0.068, T = 295 K. H12CoO14Se2Tl2, monoclinic, P121/a1 (no. 14), a = 9.387(2) Å, b = 12.600(2) Å, c = 6.308(2) Å, / = 105.70(2)°, V = 718.3 Å, Z = 2, Rgt(F) = 0.036, wRref(F ) = 0.082, T = 295 K. H12NiO14Se2Tl2, monoclinic, P121/a1 (no. 14), a = 9.334(1) Å, b = 12.572(2) Å, c = 6.298(1) Å, / = 105.70(1)°, V = 711.5 Å, Z = 2, Rgt(F) = 0.031, wRref(F ) = 0.051, T = 295 K. H12CuO14Se2Tl2, monoclinic, P121/a1 (no. 14), a = 9.400(2) Å, b = 12.539(2) Å, c = 6.315(1) Å, / = 105.01(2)°, V = 718.9 Å, Z = 2, Rgt(F) = 0.028, wRref(F ) = 0.055, T = 295 K. H12O14Se2TlZn2, monoclinic, P121/a1 (no. 14), a = 9.383(1) Å, b = 12.612(2) Å, c = 6.317(1) Å, / = 105.59(1)°, V = 720.1 Å, Z = 2, Rgt(F) = 0.027, wRref(F ) = 0.054, T = 295 K. Source of material The synthesis of all title compounds of the probably isomorphous series Tl2[M(H2O)6](SeO4)2 was performed by dissolution of equimolar amounts of thallium selenate Tl2SeO4 and M selenate hydrate MSeO4. ·. nH2O in hot destilled water and ensuing evaporation of the solvent. The M selenate hydrates contained different amounts of crystal water. For the syntheses of the Tutton’s salts with M = Mg, Co, Ni, Cu, Zn, the M selenate hexahydrates were used, for M = Mn, the M selenate pentahydrate. Differently coloured, mostly ideomorphous single crystals of dimensions up to 10 mm were obtained. Experimental details To reduce errors introduced by insufficient corrections of absorption effects, it was attempted to grind a crystal sphere in order to apply a spherical absorption correction in the course of data processing. The grinding produced an ellipsoid, whose deviation from spherical is characterized by the given max, mid and min crystal dimensions. Discussion The so far unknown crystal structures of the compounds of the thallium selenates, constituting one more important series in our studies of crystal chemistry, metal-water interaction and hydrogen bonds in Tutton salts (Rb sulfates [1], Rb selenates [2], Cs sulfates [3], Cs selenates [4], K sulfates [5], K selenates [6], Tl sulfates [7]) by single crystal and powder X-ray diffraction experiments. As all other Tutton salts, they are isotypic. Due to scattering power of Tl and data errors introduced by insufficient correction for the large absorption, the hydrogen positions could not be determined by difference Fourier mapping, as done in [16]. Therefore, all hydrogen coordinates were calculated from the linear correlations x(H(i)), y(H(i)), z(H(i)), i = 1.6 vs the cation radius R(M) (M = K, Rb, Cs), derived for each of the 6 independend hydrogen bonds of the so far studied compounds. The evaluation of the O#H···O bond lengths and angles yielded resonable hydrogen coordinates. During the structure refinements, these predicted hydrogen coordinates were kept fixed, contrary to a common variable isotropic thermal displacement parameter, assigned to all hydrogens atoms. In all cases, the agreement indices were significantly lowered by introducing the H atoms into the model, for example R1(M = Mg) = 0.0284 to R1 (M = Mg) = 0.0302. The Tutton salt structure is characterized by irregular MO8 polyhedral (here with M = Tl), d(Tl—O) = 2.796(5) 3.362(5) Å, and M(H2O)6 octahedra, which are linked to the SeO4 groups by a system of hydrogen bonds. According to expectations, the most distorted M(H2O)6 octahedron is obtained for M = Cu (Jahn-Teller distortion) with 360 Z. Kristallogr. NCS 224 (2009) 360-364 / DOI 10.1524/ncrs.2009. 0158 © by Oldenbourg Wissenschaftsverlag, München