CAS 6303-21-5 appears in our catalog under these names: Hypophosphorous acid, 50% w/w aq. soln. , Hypophosphorous acid, 50 wt.% solution in water, HYPOPHOSPHOROUS ACID, 50 WT. % SOLUTION&, HYPOPHOSPHOROUS ACID, 50 WT. % SOLUTION. Offered by: Thermo Scientific (Alfa Aesar), Thermo Scientific (Acros), Sigma-Aldrich. Available pack sizes: 50g, 500g, *4x500g, 1l, 5l, 500ML, 100G, 100ML.