Recently we showed that phosphate is a suitable precursor to chemicals traditionally synthesized from white phosphorus. Building upon these principles, we sought to develop a process for the reduction of recovered phosphate to phosphite, bypassing hazardous white phosphorus and chlorine and minimizing energy waste (Figure ). The envisioned reaction, hydride phosphorylation, can be considered as directly analogous to the canonical two-electron, one-proton reduction of a main-group element oxide: for instance, CO2 reduction to formate. Our curiosity in regard to this topic was piqued by the industrial synthesis of sodium fluorophosphate (Na2PO3F), an active ingredient in toothpaste. In a 100% atom-efficient reaction, sodium trimetaphosphate (Na3P3O9) and three equivalents of sodium fluoride are heated to 300 • C resulting in a melt and the formation of Na2PO3F: 37 Sodium trimetaphosphate (Na3P3O9), readily produced by the dehydration of phosphoric acid with sodium chloride, is the smallest cyclic phosphate with a O:P ratio of three (Figure ), identical to that in phosphite. It is therefore an attractive starting material for reduction to produce phosphite. In analogy to the industrial production of Na2PO3F, we hypothesized that the reaction of Na3P3O9 with a metal hydride such as sodium hydride (NaH) might give rise to the formation of sodium phosphite (Na2HPO3):