The new high-pressure borate hydrate Cu 3B 6O 12 · H 2O

Abstract

The new compound Cu 3B 6O 12 · H 2O, synthesized under high-pressure/high-temperature conditions of 7.5 GPa and 700 °C in a Walker-type multianvil apparatus, possesses a structure similar to CuB 2O 4 (3 × CuB 2O 4 = Cu 3B 6O 12). Via the high-pressure technique, it was possible to incorporate water molecules into the structure, leading to a symmetry reduction compared to the water free compound ( I 4 ¯ 2 d → Fdd2). Cu 3B 6O 12 · H 2O crystallizes in the orthorhombic space group Fdd2 ( Z = 8) with the lattice parameters a = 1620.4(3), b = 1657.6(3), c = 564.2(2) pm, V = 1.5154(5) nm 3, R 1 = 0.0375, wR 2 = 0.0640 (all data). The crystal structure of Cu 3B 6O 12 · H 2O is built up from corner-sharing BO 4 tetrahedra forming a three-dimensional network with channels along the c-axis. Inside these channels, the water molecules and a part of the copper ions are arranged.