An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

The first molecule detected in the interstellar medium. Methylidine radical (CH) was discovered by Walter S. Adams in 1937 using coudé spectroscopy in the direction of the bright star ζ Ophiuchi at the Mount Wilson Observatory (main CH line at 4300 Å).

Chemical term based on Gk. methy "wine," cognate with Pers. mey "wine," from Mid.Pers. mad, may "wine;" Av. maδu- "wine, mead;" cf. Skt. mádhu- "honey, wine, sweet drink," O.E. medu, E. mead, M.Du. mede, Ger. Met "mead;" O.C.S. medu, Lith. medus "honey;" Rus. m'od "honey," m'édved' "bear" (literally "honey-knower"); PIE base *médhu- "honey, sweet drink."

A → methane molecule lacking one → hydrogen atom: CH₃. → methyl chloride.

Back formation from Fr. méthylène, → methylene.

A → chemical compound (CH₃Cl), which is the most abundant → organohalogen in the Earth's atmosphere. It has both natural and synthetic origins. Also called chloromethane. Low levels of methyl chloride occur naturally in the environment. Methyl chloride is formed in the oceans by natural processes (e.g., marine phytoplankton) and from biomass burning in grasslands and forested areas (e.g., forest fires); it has been detected at low levels in air all over the world. Other sources of exposure to methyl chloride include cigarette smoke, polystyrene insulation, and aerosol propellants; home burning of wood, coal, or certain plastics. High levels may occur at chemical plants where it is made or used. Acute (short-term) exposure to high concentrations of methyl chloride in humans has caused severe neurological effects. Methyl chloride has also caused effects on the heart rate, blood pressure, liver, and kidneys in humans (United States Environmental Agency, EPA).

→ methyl; → chloride.