Cytidine 5′-monophosphate- 13 C 9 (5'-Cytidylic acid- 13 C 9 dilithium; 5'-CMP- 13 C 9 ) dilithium is 13 C-labeled Cytidine 5'-monophosphate. Cytidine 5'-monophosphate (5'-Cytidylic acid) is a nucleotide which is used as a monomer in RNA. Cytidine 5'-monophosphate consists of the nucleobase cytosine, the pentose sugar ribose, and the phosphate group.