CFC Numbering Scheme

Rule of 90

• Add 90 to the CFC number.
• Resulting digits give the number of atoms, respectively, of carbon, hydrogen, and flourine.

Examples

• CFC-11: 11 + 90 = 101 --> CCl3F
• CFC-12: 12 + 90 = 102 --> CCl2F2
• HFC-134a 134 + 90 = 224 --> H2C2F4 (CF3-CFH2)

("a" refers to how the atoms are arranged)