Hydrothermal synthesis and crystal structure of two new hydrated alkaline earth metal borates Sr3B6O11(OH)2 and Ba3B6O11(OH)2

Inorg Chem. 2012 Apr 2;51(7):3956-62. doi: 10.1021/ic202316t. Epub 2012 Mar 12.

Abstract

Two new hydrated borates Sr(3)B(6)O(11)(OH)(2) (1) and Ba(3)B(6)O(11)(OH)(2) (2) were hydrothermally synthesized. Their structures were determined by single-crystal X-ray diffraction and further characterized by IR, powder XRD, and DSC/TGA. Compound 1 crystallizes in the triclinic space group P-1 with unit cell parameters of a = 6.6275(13) Å, b = 6.6706(13) Å, c = 11.393(2) Å, α = 91.06(3)°, β = 94.50(3)°, and γ = 93.12(3)°, while compound 2 crystallizes in the noncentrosymmetric monoclinic space group Pc with a = 6.958(14) Å, b = 7.024(14) Å, c = 11.346(2) Å, and β = 90.10(3)°. In spite of the differences in symmetry and packing of the borate chains, both structures consist of the same fundamental building block (FBB) of a [B(6)O(11)(OH)(2)](-6) unit and three unique alkaline earth metal atoms.