| Title:  Phenolphthalein Sodium CAS Registry Number:  518-51-4 CAS Name:  3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone disodium salt Molecular Formula:  C20H12Na2O4 Molecular Weight:  362.29 Percent Composition:  C 66.30%, H 3.34%, Na 12.69%, O 17.66% Literature References:  Prepd from an alcoholic soln of 1 mol phenolphthalein by the addition of 2 mols NaOH.  Structure:  Buu-Hoi, Bull. Soc. Chim. [5] 8, 165 (1941). Properties:  Reddish-brown granular mass with coppery luster, or pale red powder.  Dec in air.  Soluble in water, giving a deep-red soln.  Absorption max:  550-555 nm.  The unstable enol form is colorless, as is the trisodium salt. Absorption maximum:  Absorption max:  550-555 nm     Status:  This monograph has been retired and is no longer subject to revision or update.  |