Dr. KnowCFC's (chlorofluorocarbons)
Midgley and Henne developed in 1929 a naming system for halocarbons containing carbon, hydrogen, chlorine and fluorine. Park refined the system some years later. CFC (chlorofluorocarbons) was the group name, which was later divided into sub-groups like HCFC and HFC.
The system contains a body, CFC, a number, 01234, and an alphanumeric suffix, a: CFC-01234a
- The body stands for the group type
- The number stands for the molecular formula
- The suffix stands for different isomers
CFC
ChloroFluoroCarbons
0
Number of double bonds, omitted if zero
1
Number of carbon atoms minus 1, omitted if zero
2
Number of hydrogen atoms plus 1
3
Number of fluorine atoms
4
Number of chlorine atoms replaced by bromine, always used with prefix "b" (b1, b2), omitted if zero
a
Added to identify isomers, the isomer without suffix always has the smallest mass difference on each carbon atom. If there are more isomers the suffix is counting from a - z, omitted if only one isomer exists
Example:
CFC-12b1 has no double bonds, only 1 carbon atom, no hydrogen atoms, 2 fluorine atoms, one chlorine atom replaced by bromine and no isomers = Bromochlorodifluoromethane
If it is a cyclic structure the number is prefixed with a "C" for cyclic. Sometimes some other bodies are found like FC (fluorocarbon), HC (Halocarbon) or R (refrigerant).
Abbreviation Formula
Name
CFC-11
CCl3F
trichlorofluoromethane
CFC-12
CCl2F2
dichlorodifluoromethane
CFC-113
CCl2F-CClF2
1,1,2-trichlorotrifluoroethane
HCFC-22
CHClF2
chlorodifluoromethane
HCFC-123
CHCl2-CF3
2,2-dichloro-1,1,1-trifluoroethane
HCFC-123a
CHClF-CClF2
1,2-dichloro-1,1,2-trifluoroethane
HFC-23
CHF3
trifluoromethane
HFC-134
CHF2-CHF2
1,1,2,2-tetrafluoroethane
HFC-134a
CH2F-CF3
1,2,2,2-tetrafluoroethane
R-20
CHC3
chloroform
R-22B1
CHBrF2
bromodifluoromethane
R-1120
CHCl=CCl2
trichloroethylene
R-1150
CH2=CH2
ethylene
R-C316
C4Cl2F6
1,2-dichlorohexafluorocyclobutane
Another technique for naming CFCs has been described in detail in the Journal of Chemical Education [see reference] and is called "The rule of 90". Ninety is added to the CFC number, abc, to give as a result a number, xyz, that corresponds to the Carbon-Hydrogen-Fluorine (CHF) composition. If the carbon atoms are not saturated then additional chlorine atoms are required.
Abbreviation Add 90
Empirical Composition
Formula
C
H
F
Added Cl
CFC-11
101
1
0
1
3
CCl3F
CFC-12
102
1
0
2
2
CCl2F2
HCFC-22
112
1
1
2
1
CHClF2
HCFC-123
213
2
1
3
2
CHCl2-CF3
HFC-134a
224
2
2
4
0
CH2F-CF3
Halons
The halon nomenclature system was developed by the US Army Corps of Engineers and id totally different from the CFC system. The body prefix is "Halon". There is no number for hydrogen and terminal zeros are omitted. Halon-0123
0 Number of carbon atoms
1
Number of fluorine atoms
2
Number of chlorine atoms
3
Number of bromine atoms
Examples:
Halon Code
Formula
Name
CFC Code
Halon-1211
CBrClF2
bromochlorodifluoromethane
CFC-12b1
Halon-1301
CBrF3
bromotrifluoromethane
CFC-13b1
Halon-2402
CBrF2-CBrF2
1,2-dibromo-1,1,2,2-tetrafluoroethane
CFC-114b2a
Reference:
A. A. Woolf; J. Chem. Edu. 70 (1993) 35 - 36.