Chlorine monofluoride
Chlorine monofluoride is a volatile interhalogen compound with the chemical formula. It is a colourless gas at room temperature and is stable even at high temperatures. When cooled to −100 °C, ClF condenses as a pale yellow liquid. Many of its properties are intermediate between its parent halogens, chlorine| and fluorine|.
Geometry
The molecular structure in the gas phase was determined by microwave spectroscopy; the bond length is re = 1.628341 Å.The bond length in the crystalline ClF is 1.628 Å; the lengthening relative to the free molecule is due to an interaction of the type F-Br···ClMe with a distance of 2.640 Å. In its molecular packing it shows very short intermolecular Cl···Cl contacts of 3.070 Å between neighboring molecules.
Reactivity
Chlorine monofluoride is a versatile fluorinating agent, converting metals and non-metals to their fluorides and releasing in the process. For example, it converts tungsten to tungsten hexafluoride and selenium to selenium tetrafluoride:FCl can also chlorofluorinate compounds, either by addition across a multiple bond or via oxidation. For example, it adds fluorine and chlorine to the carbon of carbon monoxide, yielding carbonyl chloride fluoride COClF, an intermediate between phosgene and carbonyl fluoride.