How To Write The Iupac Name Of An Unknown Compound . We will go through several examples for more details about the naming rules. Write iupac name of following compound. Solved Write IUPAC Names For The Compounds Below. If You from www.chegg.com (a) the longest chain has six carbons, but the longest chain that contains the carbonyl carbon has only fi ve carbons. 2) next, the appropriate primary suffix (es) must be added to the root word to indicate the saturation or unsaturation. (b) the longest chain that contains the carbonyl is six carbons;