Contributions to the stereochemistry of zirconium oxysalts—part IV: syntheses and crystal structures of Zr2(OH)2(XO4)3·4H2O (X = S, Se), Zr(SO4)2·4H2O, and Zr(SeO3)2

摘要

Abstract Zr2(OH)2(XO4)3·4H2O (X?=?S, Se), Zr(SO4)2·4H2O, and Zr(SeO3)2 were synthesized at low-hydrothermal conditions from mixtures of Zr2O2(CO3)(OH)2, the respective acids, and minor amounts of water. While Zr2(OH)2(XO4)3·4H2O (X?=?S, Se) and Zr(SO4)2·4H2O form crystals up to several tenths of a mm, Zr(SeO3)2 was mainly obtained as microcrystalline powder, single crystals rarely exceeded 10?μm in size. Samples were investigated by single-crystal X-ray techniques and in the case of Zr(SeO3)2 also by X-ray powder diffraction. The compounds Zr2(OH)2(XO4)3·4H2O (X?=?S, Se) crystallize in the Ce2(OH)2(SO4)3·4H2O structure type (C2/c, Z?=?4, a?=?13.034(2) / 13.308(3), b?=?6.500(1) / 6.683(2), c?=?15.056(3) / 15.383(4) ?, β?=?96.27(1) / 96.81(1)°, V?=?1267.9(4) / 1358.5(6) ?3 for X?=?S / Se, respectively). Tetragonal aniprisms Zr[8]O8 are edge-connected to dimers that share corners with XO4 tetrahedra forming a three-dimensional network. Zr(SO4)2·4H2O (Fddd, Z?=?8, a?=?5.498(1), b?=?11.618(3), c?=?25.893(6) ?, V?=?1653.9(6) ?3) is isotypic with the respective selenate compound. Occasionally, pseudomerohedral twinning is observed, simulating a larger monoclinic C-centered unit cell. Again, tetragonal antiprisms Zr[8]O8 are formed; however, they are corner-linked with SO4 tetrahedra to Zr(SO4)2 layers interconnected solely by hydrogen bonds. Zr(SeO3)2 crystallizes in P21/c, Z?=?2; a?=?4.9724(3), b?=?8.5992(5), c?=?6.9447(3) ?, β?=?110.128(3)°, V?=?278.81(3) ?3 (unit cell from powder data) and belongs to the β-Sn(SeO3)2 structure type established further for Ti(SeO3)2 and Pb(SeO3)2. Isolated ZrO6 octahedra share corners with the selenite groups forming a three-dimensional network.Graphical abstract