Ponceau 6R, or Crystal ponceau 6R, Crystal scarlet, Brilliant crystal scarlet 6R, Acid Red 44, or C.I. 16250, is a red azo dye. It is soluble in water and slightly soluble in ethanol. It is used as a food dye, with E number E126. It is also used in histology, for staining fibrin with the MSB Trichrome stain. It usually comes as disodium salt.

CAS：2766-77-0
中文别名：酸性红44;
英文别名：Crystal Ponceau 6R;brilliant crystal scarlet;CRYSTAL SCARLET;Acid Red 44,Brilliant Crystal Scarlet,Crystal Scarlet;Acid Red 44 Brilliant Crystal Scarlet Crystal Ponceau 6R Crystal Scarlet Ponceau 6R;Acid Ponceau 6R;CRYSTAL PONCEAU;ACID RED 44;CRYSTAL PONCEAU 6R;C.I. Acid Red 44;Crystal Ponceau?R;
分子式：C20H12N2Na2O7S2
分子量：502.428
精确质量：501.988
Psa：176.11
Logp：6.0838

UNII：W8UOR0932R

熔点：>300ºC(lit.)