Alizarin red C (Alizarin C, alizarin red S) - a chemical compound series hydroxyanthraquinones.
Is an orange-yellow substance soluble in water and ethanol insoluble in benzene, alkanes, chloroform.
Alizarin red C is used as a reagent for the photometric determination of cations of aluminum, scandium, yttrium, and fluoride ions. This reaction is based on the interaction of colored complexes.
Alizarin red C can also be used as acid-base indicators: the transition pH 3,7-5,2 from yellow to pink color and pH 10,0-12,0 from yellow to violet color.