Editing Chlorofluorocarbon (section)

==Classes of compounds and Numbering System==
*Chlorofluorocarbons (CFCs): when derived from methane and ethane, these compounds have the formulae {{chem2|CCl_{m}F_{4-m}|}} and {{chem2|C2Cl_{m}F_{6-m}|}}, where m is nonzero.
*Hydro-chlorofluorocarbons (HCFCs): when derived from methane and ethane, these compounds have the formula {{chem2|CCl_{m}F_{n}H_{4-m-n}|}} and {{chem2|C2Cl_{x}F_{y}H_{6-x-y}|}}, where m, n, x, and y are nonzero.
*[[Bromofluorocarbon]]s (BFCs): have formulae similar to the CFCs and HCFCs, but also include bromine.
*Hydrofluorocarbons (HFCs): when derived from [[methane]], [[ethane]], [[propane]], and [[butane]], these compounds have the respective formulae {{chem2|CF_{m}H_{4-m}|}}, {{chem2|C2F_{m}H_{6-m}|}}, {{chem2|C3F_{m}H_{8-m}|}}, and {{chem2|C4F_{m}H_{10-m}|}}, where m is nonzero.

=== Numbering system ===
{{Main|Refrigerant#Refrigerants by class and R-number}} {{See also|List of refrigerants}}

A special numbering system is used for fluorinated alkanes, prefixed with Freon-, R-, CFC- and HCFC-, where the rightmost value indicates the number of fluorine atoms, the next value to the left is the number of hydrogen atoms ''plus'' 1, and the next value to the left is the number of carbon atoms ''less'' one (zeroes are not stated), and the remaining atoms are [[chlorine]].

Freon-12, for example, indicates a methane derivative (only two numbers) containing two fluorine atoms (the second 2) and no hydrogen (1 − 1 = 0). It is therefore {{chem2|CCl2F2}}.<ref>{{Cite web |title=Ice Breaker: Refrigerant Numbering System Explained {{!}} ACHR News |url=https://www.achrnews.com/articles/108910-ice-breaker-refrigerant-numbering-system-explained |access-date=2023-12-12 |website=www.achrnews.com |language=en}}</ref>

Another equation that can be applied to get the correct molecular formula of the CFC/R/Freon class compounds is to take the numbering and add 90 to it. The resulting value will give the number of carbons as the first numeral, the second numeral gives the number of hydrogen atoms, and the third numeral gives the number of fluorine atoms. The rest of the unaccounted carbon bonds are occupied by chlorine atoms. The value of this equation is always a three figure number. An easy example is that of CFC-12, which gives: 90+12=102 -> 1 carbon, 0 hydrogens, 2 fluorine atoms, and hence 2 chlorine atoms resulting in {{chem2|CCl2F2}}. The main advantage of this method of deducing the molecular composition in comparison with the method described in the paragraph above is that it gives the number of carbon atoms of the molecule.<ref>{{Cite web |last=Sievänen |first=Esa |date=2020-02-26 |title=Numbering of refrigerants • Darment |url=https://darment.eu/numbering-of-refrigerants-ansi-ashrae-standard/ |access-date=2023-12-12 |website=Darment |language=en-GB}}</ref>

[[Freon]]s containing bromine are signified by four numbers. [[Isomer]]s, which are common for ethane and propane derivatives, are indicated by letters following the numbers:

{| class="wikitable collapsible" cellpadding="0" style="margin:auto; margin:0; border-color:#c0c090; width:100%;"
!+ colspan="4" style="text-align:center; background:#ffdead;"| Principal CFCs
|-
! style="text-align:center; background:#ffdead;"| Systematic name
! style="text-align:center; background:#ffdead;"| Common/trivial<br> name(s), code
! style="text-align:center; background:#ffdead;"| Boiling point (°C)
! style="text-align:center; background:#ffdead;"| Formula
|-
| [[Trichlorofluoromethane]]
| Freon-11, R-11, CFC-11
| 23.77
| {{chem2|CCl3F}}
|-
| [[Dichlorodifluoromethane]]
| Freon-12, R-12, CFC-12
| −29.8
| {{chem2|CCl2F2}}
|-
| [[Chlorotrifluoromethane]]
| Freon-13, R-13, CFC-13
| −81
| {{chem2|CClF3}}
|-
| [[Dichlorofluoromethane]]
| R-21, HCFC-21
| 8.9
| {{chem2|CHCl2F}}
|-
| [[Chlorodifluoromethane]]
| R-22, HCFC-22
| −40.8
| {{chem2|CHClF2}}
|-
| [[Chlorofluoromethane]]
| Freon 31, R-31, HCFC-31
| −9.1
| {{chem2|CH2ClF}}
|-
| [[Bromochlorodifluoromethane]]
| BCF, Halon 1211, H-1211, Freon 12B1
| −3.7
| {{chem2|CBrClF2}}
|-
| [[1,1,2-Trichloro-1,2,2-trifluoroethane]]
| Freon 113, R-113, CFC-113, 1,1,2-Trichlorotrifluoroethane
| 47.7
| {{chem2|Cl2FC\sCClF2}}
|-
| [[1,1,1-Trichloro-2,2,2-trifluoroethane]]
| Freon 113a, R-113a, CFC-113a
| 45.9
| {{chem2|Cl3C\sCF3}}
|-
| [[1,2-Dichlorotetrafluoroethane|1,2-Dichloro-1,1,2,2-tetrafluoroethane]]
| Freon 114, R-114, CFC-114, Dichlorotetrafluoroethane
| 3.8
| {{chem2|ClF2C\sCClF2}}
|-
|[[1,1-Dichlorotetrafluoroethane|1,1-Dichloro-1,2,2,2-tetrafluoroethane]]
|CFC-114a, R-114a
|3.4
| {{chem2|Cl2FC\sCF3}}
|-
| [[1-Chloro-1,1,2,2,2-pentafluoroethane]]
| Freon 115, R-115, CFC-115, Chloropentafluoroethane
| −38
| {{chem2|ClF2C\sCF3}}
|-
| [[2-Chloro-1,1,1,2-tetrafluoroethane]]
| R-124, HCFC-124
| −12
| {{chem2|CHFClCF3}}
|-
| [[1,1-Dichloro-1-fluoroethane]]
| R-141b, HCFC-141b
| 32
| {{chem2|Cl2FC\sCH3}}
|-
| [[1-Chloro-1,1-difluoroethane]]
| R-142b, HCFC-142b
| −9.2
| {{chem2|ClF2C\sCH3}}
|-
| [[Tetrachloro-1,2-difluoroethane]]
| Freon 112, R-112, CFC-112
| 91.5
| {{chem2|CCl2FCCl2F}}
|-
| [[Tetrachloro-1,1-difluoroethane]]
| Freon 112a, R-112a, CFC-112a
| 91.5
| {{chem2|CClF2CCl3}}
|-
| [[1,1,2-Trichlorotrifluoroethane]]
| Freon 113, R-113, CFC-113
| 48
| {{chem2|CCl2FCClF2}}
|-
| 1-bromo-2-chloro-1,1,2-trifluoroethane
| Halon 2311a
| 51.7
| {{chem2|CHClFCBrF2}}
|-
| [[2-bromo-2-chloro-1,1,1-trifluoroethane]]
| Halon 2311
| 50.2
| {{chem2|CF3CHBrCl}}
|-
| 1,1-Dichloro-2,2,3,3,3-pentafluoropropane
| R-225ca, HCFC-225ca
| 51
| {{chem2|CF3CF2CHCl2}}
|-
| [[1,3-Dichloro-1,2,2,3,3-pentafluoropropane]]
| R-225cb, HCFC-225cb
| 56
| {{chem2|CClF2CF2CHClF}}
|}