Radium Metaphosphates

There is no record of either of these salts ever having been prepared, although they could be made by several methods. The best one would be to react metaphosphoric acid and the hydroxide, oxide or carbonate of radium in the solid state:
RaCO3 + HPO3 + heat ? Ra(PO3)2 +H2O + CO2
The best temperature to use is about 700°C. It has no CAS number. The molecular weight is expected to be 383.9663 g/mol. This compound can also be prepared by the aqueous reactions:
NaPO3 (aq) + RaCl2 (aq) ? Ra(PO3)2 (solid) + NaCl (aq)
or
Ra(OH)2 (solid) + 2HPO3 (aq) ? Ra(PO3)2 (solid) + 2H2O
Whether hydrates form remains unknown at this date. The only reference in the scientific literature concerns the removal of radioactive ²²⁶Ra from drinking water by the addition of sodium polyphosphate. Radium polyphosphate is sufficiently insoluble so that all of the radium polyphosphate could be filtered out and subjected to proper disposal.