Non-molecular monovalent metal organophosphonates and diphosphonates

The solid state chemistry of non-molecular monovalent metal organophosphonates and diphosphonates is relatively new and evolving research arena. The syntheses and structural characterization of about fifty such compounds are reported in the literature. They are a variety of mono- and di-phosphonates of inorganic monovalent cations, namely, alkali metal, thallium, cuprous, silver and mercurous ions and also ammonium ions. They have x:2 (x = 1–4) ratios of metal to phosphonate moieties and possess mostly layered and pillared-layered structures. Some of them function as solid Brönsted acids and exhibit proton conductivity.