It is one of the four main bases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached. The nucleoside of cytosine is cytidine. In Watson-Crick base pairing, it forms three hydrogen bonds with guanine.Specifications:Ultra Pure GradeEm (275 nm, 0.1M HCl): >9,900 Appearance: White SolidChEBI : Not available.Crystal_Structure : Not available.Density : 0.48 g/cm3InChI : Not available.InChIKey : Not available.Melting Point: >300 °CRTECS Number: UW7350150