Guanidinium and Imidazolium Borates Containing the First Examples of an Isolated Nonaborate Oxoanion: [B₉O₁₂(OH)₆]³^-

Abstract

Boron−oxygen compounds have considerable mineralogical and industrial importance. Many examples of isolated boron oxoanions containing one to six borons occur in mineral and synthetic borates. However, isolated boron oxoanions having more than six borons are rare, and there are no previous examples having nine borons. Described is the synthesis and structural characterization of crystalline guanidinium and imidazolium borates, [C(NH2)3]3[B9O12(OH)6] and [C3H5N2]3[B9O12(OH)6], containing the first examples of the isolated nonaborate anion [B9O12(OH)6]3-.