Trihalomethanes (THMs) are chemical compounds in which three of the four hydrogen atoms of methane (CH₄) are replaced by halogen atoms. Many trihalomethanes find uses in industry as solvents or refrigerants. THMs are also environmental pollutants, and many are considered carcinogenic. A chemical compound is a chemical substance formed from two or more elements, with a fixed ratio determining the composition. ... R-phrases S-phrases , , , Flash point −188°C Autoignition temperature 537°C Explosive limits 5–15% Supplementary data page Structure and properties Thermodynamic data Spectral data UV, IR, NMR, MS Related compounds Related alkanes Ethane Propane Related compounds Methanol Chloromethane Except where noted otherwise, data are given for materials in... The halogens are a chemical series. ... A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... A refrigerant is a compound used in a heat cycle that undergoes a phase change from a gas to a liquid and back. ... // Carcinogen In pathology, a carcinogen is any substance or agent that promotes cancer. ...

The International Union of Pure and Applied Chemistry (IUPAC) is an international non-governmental organization devoted to the advancement of chemistry. ... Trifluoromethane (CHF3), also known as fluoroform, is one of the haloalkanes with minor ozone depletion, as it doesnt contain any chlorine. ... Freon is a trade name for a group of chlorofluorocarbons used primarily as a refrigerant. ... Cl | F--C--F | H Chlorodifluoromethane or difluoromonochloromethane is a hydrochlorofluorocarbon (HCFC) with chemical formula CHClF2 and CAS number 75-45-6. ... PEL-TWA (OSHA) 50 ppm (240 mg/m3) IDLH (NIOSH) 500 ppm Flash point non-flammable RTECS number FS9100000 Supplementary data page Structure & properties n, εr, etc. ... Bromoform (CHBr3) is a pale yellowish liquid with a sweet odor, a halomethane similar to chloroform. ... The compound iodoform is a yellow, crystalline, volatile substance, I3CH, having a penetrating odor (in older chemistry texts, the smell is sometimes referred to as the smell of hospitals) and sweetish taste, and analogous to chloroform. ...

Industrial uses

Refrigerants

Trifluoromethane and chlorodifluoromethane are both used as refrigerants in some applications. Trihalomethanes released to the environment break down faster than chlorofluorocarbons (CFCs), thereby doing less damage to the ozone layer (if they contain chlorine). Chlorodifluoromethane is a refrigerant HCFC, or hydrochlorofluorocarbon, while fluoroform is an HFC, or hydrofluorocarbon. Fluoroform is not ozone depleting. It has been suggested that Refrigerator be merged into this article or section. ... A refrigerant is a compound used in a heat cycle that undergoes a phase change from a gas to a liquid and back. ... Possible meanings: Certified Financial Consultant Chelsea Football Club Child and Family Canada Chlorofluorocarbon Combined Federal Campaign haloalkane This page concerning a three-letter acronym or abbreviation is a disambiguation page—a list of articles associated with the same title. ... The ozone layer, or ozonosphere layer (rarely used term), is that part of the Earths atmosphere which contains relatively high concentrations of ozone (O3). ... Hydrochlorofluorocarbons (HCFCs) is one of a class of fluorocarbon compounds that are used primarily as chlorofluorocarbon (CFC) substitutes. ... CFC molecules CFCs (chlorofluorocarbons) are a family of artificial chemical compounds containing chlorine, fluorine and carbon. ...

Unfortunately, the breakdown of trihalomethane HCFCs does still result in the creation of some free chlorine radicals in the upper atmosphere and subsequent ozone destruction. Ideally, HCFCs will be phased out entirely in favour of entirely nonchlorinated refrigerants.

Solvents

Chloroform (trichloromethane) is a very common solvent used in organic chemistry. It is a significantly less polar solvent than water, well-suited to dissolving many organic compounds. A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... The Earths magnetic field, which is approximately a dipole. ... An organic compound is any member of a large class of chemical compounds whose molecules contain carbon, with the exception of carbides, carbonates, carbon oxides and gases containing carbon. ...

Although still toxic and potentially carcinogenic, chloroform is significantly less harmful than carbon tetrachloride. Because of the health and regulatory issues associated with the use of carbon tetrachloride, in modern chemistry laboratories chloroform is used a cheaper, cleaner alternative wherever possible. R-phrases , , , , S-phrases , , , , , Flash point non flammable RTECS number FG4900000 Supplementary data page Structure and properties n, εr, etc. ...

Water pollutants

Trihalomethanes are formed as a byproduct when chlorine or bromine are used to purify water for drinking. They result from the reaction of chlorine and/or bromine with organic matter in the water being treated. The THMs produced may have adverse health effects at high concentrations, and many governments set limits on the amount permissible in drinking water. In the United States, the EPA limits the total concentration of chloroform, bromoform, bromodichloromethane, and dibromochloromethane to 80 parts per billion in treated water. This number is called "total trihalomethanes" (TTHM). General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Atomic mass 35. ... General Name, Symbol, Number bromine, Br, 35 Chemical series halogens Group, Period, Block 17, 4, p Appearance gas/liquid: red-brown solid: metallic luster Atomic mass 79. ... EPA redirects here. ...

Chloroform is also formed in swimming pools which are disinfected with chlorine or hypochlorite in the haloform reaction with organic substances (urine, sweat and skin particles). The reaction to phosgene under the influence of UV is also possible. PEL-TWA (OSHA) 50 ppm (240 mg/m3) IDLH (NIOSH) 500 ppm Flash point non-flammable RTECS number FS9100000 Supplementary data page Structure & properties n, εr, etc. ... 50 meter indoor swimming pool A swimming pool, swimming bath, or wading pool is an artificially enclosed body of water intended for recreational or competitive swimming, or for other bathing activities that do not involve swimming, i. ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Atomic mass 35. ... The hypochlorite ion is ClO-. A hypochlorite compound is a chemical compound containing this group, with chlorine in oxidation state +1. ... The haloform reaction is a chemical reaction where a haloform CHX3) is produced by the multiple halogenation of a methyl ketone (a molecule containing the R-CO-CH3 group) in the presence of a base. ... Urine is liquid waste excreted by the kidneys and is produced by the process of filtration. ... SWEAT is an OLN/TSN show hosted by Julie Zwillich that aired in 2003-2004. ... Diagram of the layers of human skin In zootomy and dermatology, skin is an organ of the integumentary system made up of a layer of tissues that protect underlying muscles and organs. ... Phosgene (also known as carbonyl chloride, COCl2) is a highly toxic gas or refrigerated liquid that was used as a chemical weapon in World War I. It has no color, but is detectable in air by its odor, which resembles moldy hay. ...

External links

• National Pollutant Inventory - Chloroform and trichloromethane