K[ZnBP2O8] and A[ZnBP2O8] (A=NH4+, Rb+, Cs+): Zincoborophosphates as a New Class of Compounds with Tetrahedral Framework Structures

Abstract

Tetrahedral framework structures with topologies that show close relationships to the feldspar group or to gismondine are formed by the zincoborophosphates A[ZnBP2O8] (see picture). The compounds are readily accessible under mild hydrothermal conditions (Tmax=170°C) and are thermally remarkably stable (for example, 940°C for A=Cs). Metalloborophosphates are a new class of compounds, which are expected to provide access to zeolite-like microporous systems.