Acid Red 51 CAS #568-63-8

Acid Red 51, also known as Erythrosin B sodium salt, Erythrosin, has a CAS number of 568-63-8.
It is a red to brown powder that is easily soluble in water. The aqueous solution is a strong blue color, and it is magenta when hydrochloric acid or sodium hydroxide is added. Its molecular formula is C_{20} H_{6} I_{4} Na_{2} O_{5}, and its molecular weight is 879.86.
Acid Red 51 is mainly used as a biological stain, such as Jackson staining in plant tissue dissection; counterstaining after hematoxylin staining; staining of keratin and mucus in Kreyberg’s method, etc.
When using Acid Red 51, you need to pay attention to safety. Its hazard code is Xn (harmful), the risk statement is R22 (harmful if swallowed), and the safety statement is S36/24/25 (wear appropriate protective clothing and avoid contact with skin and eyes).