Iodine monofluoride

Iodine monofluoride
Names
	IUPAC name Iodine monofluoride
	Other names Iodine fluoride
Identifiers
CAS Number	13873-84-2 ;
3D model (JSmol)	Interactive image;
ChemSpider	123150 ;
PubChem CID	139637;
CompTox Dashboard (EPA)	DTXSID50160764 ;
	InChI InChI=1S/FI/c1-2 Key: PDJAZCSYYQODQF-UHFFFAOYSA-N ; InChI=1/FI/c1-2 Key: PDJAZCSYYQODQF-UHFFFAOYAT;
	SMILES FI;
Properties
Chemical formula	IF
Molar mass	145.903 g/mol
Appearance	unstable brown solid
Melting point	−45 °C (−49 °F; 228 K)
Related compounds
Other anions	Iodine monochloride; Iodine monobromide; Astatine monoiodide
Other cations	Chlorine monofluoride; Bromine monofluoride
Related compounds	Iodine trifluoride; Iodine pentafluoride; Iodine heptafluoride
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Iodine monofluoride is an interhalogen compound of iodine and fluorine with formula IF. It is a chocolate-brown solid that decomposes at 0 °C,^[1] disproportionating to elemental iodine and iodine pentafluoride:

5 IF → 2 I₂ + IF₅

However, its molecular properties can still be precisely determined by spectroscopy: the iodine-fluorine distance is 190.9 pm and the I−F bond dissociation energy is around 277 kJ mol⁻¹. At 298 K, its standard enthalpy change of formation is Δ_fH° = −95.4 kJ mol⁻¹, and its Gibbs free energy is Δ_fG° = −117.6 kJ mol⁻¹.

It can be generated, albeit only fleetingly, by the reaction of the elements at −45 °C in CCl₃F:

I₂ + F₂ → 2 IF

It can also be generated by the reaction of iodine with iodine trifluoride at −78 °C in CCl₃F:

I₂ + IF₃ → 3 IF

The reaction of iodine with silver(I) fluoride at 0 °C also yields iodine monofluoride:

I₂ + AgF → IF + AgI

Reactions

Iodine monofluoride is used to produce pure nitrogen triiodide:^[2]

BN + 3 IF → NI₃ + BF₃

^ Eagleson, Mary (1994). Concise Encyclopedia of Chemistry. Walter de Gruyter. ISBN 978-3-11-011451-5.
^ Inis Tornieporth-Oetting; Thomas Klapötke (1990). "Nitrogen Triiodide". Angewandte Chemie International Edition. 29 (6). VCH Verlagsgesellschaft mbH: 677–679. doi:10.1002/anie.199006771.