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system
Provide the molecular formula for the IUPAC named substance (3aS)-1-(3-tert-butylphenoxy)-1-oxido-2-phenyl-3a,4,5,6-tetrahydro-3H-pyrrolo[1,2-c][1,3,2]diazaphosphol-1-ium .
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C21H27N2O2P
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