High microwave susceptibility of NaH₂PO₄.2H₂O: rapid synthesis of crystalline and glassy phosphates with NASICON-type chemistry

Abstract

High microwave susceptibility of NaH₂PO₄.2H₂O has been discovered. This hydrated acid phosphate of sodium can be heated upto 1000 K or more when exposed to 2.45 GHz microwaves. Using this, a novel microwave-assisted preparation of a number of important crystalline and glassy materials with NASICON-type chemistry has been accomplished in less than 8 min which is only a fraction of the time required for conventional synthetic procedures. The present single-shot approach to the preparation of phosphates is attractive in terms of its simplicity, rapidity, and general applicability. A "step-ladder" heating mechanism has been proposed to account for the high microwave absorbing ability of NaH₂PO₄.2H₂O.