Iodine monofluoride

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| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 446238943

| ImageFileL1 = Iodine-monofluoride-2D.png

| ImageFileR1 = Iodine-monofluoride-3D-vdW.png

| IUPACName = Iodine monofluoride

| OtherNames = Iodine fluoride

|Section1={{Chembox Identifiers

| CASNo_Ref = {{cascite|correct|??}}

| CASNo = 13873-84-2

| PubChem = 139637

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 123150

| SMILES = FI

| InChI = 1/FI/c1-2

| InChIKey = PDJAZCSYYQODQF-UHFFFAOYAT

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/FI/c1-2

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = PDJAZCSYYQODQF-UHFFFAOYSA-N }}

|Section2={{Chembox Properties

| Formula = IF

| MolarMass = 145.903 g/mol

| Appearance = unstable brown solid

| Density =

| MeltingPtC = -45

| BoilingPt =

| Solubility = }}

|Section3={{Chembox Hazards

| MainHazards =

| FlashPt =

| AutoignitionPt = }}

|Section4={{Chembox Related

| OtherAnions = Iodine monochloride
Iodine monobromide
Astatine monoiodide

| OtherCations = Chlorine monofluoride
Bromine monofluoride

| OtherCompounds = Iodine trifluoride
Iodine pentafluoride
Iodine heptafluoride}}

}}

Iodine monofluoride is an interhalogen compound of iodine and fluorine with formula IF. It is a chocolate-brown solid that decomposes at 0 °C,{{cite book|first=Mary |last=Eagleson |date=1994 |title=Concise Encyclopedia of Chemistry |publisher=Walter de Gruyter |ISBN=978-3-11-011451-5}} 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