Syntheses and crystal structures of the manganese hydroxide halides Mn-5(OH)(6)Cl-4, Mn-5(OH)(7)I-3, and Mn-7(OH)(10)I-4

Single-crystals of the new manganese hydroxide halides Mn-5(OH)(6)Cl-4, Mn-5(OH)(7)I-3, and Mn-7(OH)(10)I-4 were obtained by means of high-pressure/high-temperature synthesis in a Walker-type multianvil apparatus. The chloride crystallizes in the monoclinic space group P2(1)/c (no. 14) with the lattice parameters (single-crystal data) a = 592.55(8), b = 1699.7(2), c = 597.33(8) pm, and beta = 112.58(1)degrees. The iodides crystallize in the triclinic space group P (1) over bar (no. 2) with a = 653.16(2), b = 905.98(3), c = 1242.98(4) pm, a = 114.21(1)degrees, beta = 99.91(1)degrees, and gamma = 94.37(1)degrees for Mn-5(OH)(7)I-3 and a = 656.90(3), b = 906.59(4), c = 909.32(4) pm, alpha = 119.29(1)degrees, beta = 97.99(1)degrees, and gamma = 95.03(1)degrees for Mn-7(OH)(10)I-4. The crystal structures consist of edge-sharing Mn(OH)(6-n)X-n (X = Cl, I; n = 1, 2, 3) octahedra arranged in stacked sheets. Adjacent layers are connected by hydrogen bonds of type O-H center dot center dot center dot X, confirmed by further characterization of single-crystals by IR-spectroscopy. The crystal chemical relationship with the aristotype Mg(OH)(2) (brucite) is discussed on the basis of Barnighausen trees (group-subgroup relations).