Strontium phosphite can have the molecular formula
of SrHPO3 or Sr(H2PO3)2. It is the former that appears
when a solution of phosphorous acid is reacted with
the oxide, hydroxide or carbonate:
SrO +H3PO3 ? SrHPO3 +H2O
The product is a hemimonohydrate, i.e. SrHPO3·
1.5H2O. It can also be prepared by the action of ammonium
phosphite on strontium chloride:
SrCl2 (aq) +NH4HPO3 (aq) ? SrHPO3·1.5H2O
+NH4Cl2 (aq)
The dihydrogen
phosphite compound is prepared by reaction of
strontium carbonate and sodium phosphite:
SrCO3 + 2NaH2PO3 (aq)0Sr(H2PO3)2 (aq)
+ 2NaOH (aq) + CO2
The salt is soluble in solution and is evaporated via
vacuum. In contrast, the monohydrogen compound is
relatively insoluble in water.
Very little information on these compounds is available
in the scientific or technical literature.
