Carbon oxohalides are a group of chemical compounds that contain only carbon, oxygen and halogen atoms: fluorine, chlorine, bromine and iodine. They include carbonyl halides, , and oxalyl halides, , where X = F, Cl, Br or I. The halogen atoms X do not have to be identical; they differ in mixed oxohalides. Most combinations of halogens exist but carbonyl iodide, , is unknown. The carbon–oxygen bond length in carbonyl halides (1.13–1.17 Å) is shorter than in other carbonyl compounds such as aldehydes and ketones, carboxylic acids, esters and amides (1.20–1.21 Å). They are reactive reagents for halogenation, acylation and dehydration reactions.
+Carbon oxohalides Name Formula Melting point / °C Boiling point / °C C–O bond length / Å Carbonyl fluoride −114 −83.1 1.174 Carbonyl chloride fluoride COFCl −42 Carbonyl bromide fluoride COFBr −20.6 Phosgene −127.8 +7.6 1.166 Carbonyl fluoride iodide COFI −90 +23.4 Carbonyl bromide chloride COClBr Carbonyl bromide +64.5 1.13 Oxalyl fluoride −3 +26.6 Oxalyl chloride −16 +63 Diphosgene −57 +128 Triphosgene +80 +206
See also
Oxohalide Carbon compounds#Carbon halides Carbon compounds#Carbon-oxygen compounds Oxocarbon
References