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9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is a phosphinic ester wherein a phosphorus and an oxygen atom are integrated into the backbone of a phenanthrene.
D 0438 (OTTO) 9,10-Dihydro-9-oxa-10-phosphaphenanthrene 10-oxide, 97% Cas 35948-25-5 - used as a flame retardant, and a reactant for synthesizing a monomer.