Synthesis, structure, and properties of a novel hydrated borate Rb4[B4O5(OH)4]2·3H2O

Rb4[B4O5(OH)4]2·3H2O has been grown by slow evaporation method with crystal sizes up to 11 mm × 7 mm × 4 mm. Its crystal structure has been determined by single-crystal X-ray diffraction and further characterized by powder X-ray diffraction (XRD), IR, and TGA. It crystallizes in the orthorhombic space group Pbcn, with a = 16.3984(14) Å, b = 7.7850(7) Å, c = 16.0763(16) Å, and Z = 4. It contains isolated [B4O5(OH)4]2− polyanions, free water molecules and Rb cations. The Rb(1) and Rb(2) atoms are coordinated by nine and ten oxygen atoms, respectively. Connections between isolated [B4O5(OH)4]2− polyanions are provided by Rb polyhedra and the hydrogen-bonding to form a three-dimensional network.

Graphical abstractRb4[B4O5(OH)4]2·3H2O contains isolated [B4O5(OH)4]2− polyanions, free water molecules and Rb cations. The Rb(1) and Rb(2) atoms are coordinated by nine and ten oxygen atoms, respectively. Connections between isolated [B4O5(OH)4]2− polyanions are provided by Rb polyhedra and the hydrogen-bonding to form a three-dimensional network. (The packing diagram of RBOH. The green spheres are Rb atoms; the red spheres are O atoms; the orange spheres are H atoms; BO4 tetrahedra are shown in light blue, BO3 triangles are shown in light red, respectively).Figure optionsDownload full-size imageDownload as PowerPoint slide