Facile Assembly of an Unusual Lead Borate with Different Cluster Building Units via a Hydrothermal Process

Pb­(BO2)2·H2O as sources of B and Pb via a simple hydrothermal process provided the first binodal 5,9-connected lead borate, Pb6B4O11(OH)2 (1). Compound 1 crystallizes in the orthorhombic space group Pnma. The crystal structure is composed of different cluster building units of B4O9 and Pb6O4. Compound 1 has an optical band gap of 3.24 eV.