Hydrothermal Synthesis and Crystal Structures of Na2Be3(SeO3)4·H2O and Cs2[Mg(H2O)6]3(SeO3)4

Abstract

The selenites, Na2Be3(SeO3)4·H2O and Cs2[Mg(H2O)6]3(SeO3)4, were synthesized under hydrothermal conditions. The crystal structures of Na2Be3(SeO3)4·H2O and Cs2[Mg(H2O)6]3(SeO3)4 were determined by single‐crystal X‐ray diffractions. Na2Be3(SeO3)4·H2O crystallizes in the triclinic space group P1 (no. 2) with unit cell parameters a = 4.8493(9), b = 12.013(2), c = 12.077(2) Å, and Z = 2, whereas Cs2[Mg(H2O)6]3(SeO3)4 crystallizes in the monoclinic space group C2/m (no. 12) with lattice cell parameters a = 12.596(6), b = 7.297(4), c = 16.914(8) Å, and Z = 2. Na2Be3(SeO3)4·H2O features a three‐dimensional open framework structure formed by BeO4 tetrahedra and SeO3 trigonal pyramids. Na cations and H2O molecules are located in different tunnels. Cs2[Mg(H2O)6]3(SeO3)4 has a structure composed of isolated [Mg(H2O)6] octahedra and SeO3 trigonal pyramids interacted by hydrogen bonds, and Cs cations are resided in‐between. Both compounds were characterized by thermogravimetric analysis and FT‐IR spectroscopy.