Ammonium Fluoride - Wikipedia

Ammonium fluoride

Names
IUPAC name Ammonium fluoride
Other names Neutral ammonium fluoride
Identifiers
CAS Number	12125-01-8 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:66871
ChemSpider	23806 Y
ECHA InfoCard	100.031.975
EC Number	235-185-9
PubChem CID	25516
RTECS number	BQ6300000
UNII	4QT928IM0A
UN number	2505
CompTox Dashboard (EPA)	DTXSID6050463
InChI InChI=1S/FH.H3N/h1H;1H3 YKey: LDDQLRUQCUTJBB-UHFFFAOYSA-N Y InChI=1/FH.H3N/h1H;1H3Key: LDDQLRUQCUTJBB-UHFFFAOYAM
SMILES [F-].[NH4+]
Properties
Chemical formula	NH4F
Molar mass	37.037 g/mol
Appearance	White crystalline solid hygroscopic
Density	1.009 g/cm3
Melting point	100 °C (212 °F; 373 K) (decomposes)
Solubility in water	83.5 g/100 ml (25 °C) [1]
Solubility	slightly soluble in alcohol, insoluble in liquid ammonia
Magnetic susceptibility (χ)	−23.0×10−6 cm3/mol
Structure
Crystal structure	Wurtzite structure (hexagonal)
Hazards
GHS labelling:[2]
Pictograms
Signal word	Danger
Hazard statements	H301, H311, H314, H330, H331
Precautionary statements	P260, P261, P264, P270, P271, P280, P284, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P311, P312, P320, P321, P322, P330, P361, P363, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 0 0
Flash point	Non-flammable
Safety data sheet (SDS)	ICSC 1223
Related compounds
Other anions	Ammonium chlorideAmmonium bromideAmmonium iodide
Other cations	Sodium fluoridePotassium fluoride
Related compounds	Ammonium bifluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Chemical compound

Ammonium fluoride is the inorganic compound with the formula NH4F. It crystallizes as small colourless prisms, having a sharp saline taste, and is highly soluble in water. Like all fluoride salts, it is moderately toxic in both acute and chronic overdose.[3]

Crystal structure

[edit]

Ammonium fluoride adopts the wurtzite crystal structure, in which both the ammonium cations and the fluoride anions are stacked in ABABAB... layers, each being tetrahedrally surrounded by four of the other. There are N−H···F hydrogen bonds between the anions and cations.[4] This structure is very similar to ice, and ammonium fluoride is the only substance which can form mixed crystals with water.[5]

Reactions

[edit]

On passing hydrogen fluoride gas (in excess) through the salt, ammonium fluoride absorbs the gas to form the addition compound ammonium bifluoride. The reaction occurring is:

NH4F + HF → NH4HF2

Ammonium fluoride sublimes when heated—a property common among ammonium salts. In the sublimation, the salt decomposes to ammonia and hydrogen fluoride; the two gases can still recombine, i.e. the reaction is reversible:

[NH4]F ⇌ NH3 + HF

Uses

[edit]

This substance is commonly called "commercial ammonium fluoride". The word "neutral" is sometimes added to "ammonium fluoride" to represent the neutral salt [NH4]F as opposed to the "acid salt" (NH4HF2). The acid salt is usually used in preference to the neutral salt in the etching of glass and related silicates. This property is shared among all soluble fluorides. For this reason it cannot be handled in glass test tubes or apparatus during laboratory work.

Ammonium fluoride is a critical component of buffered oxide etch (BOE), a wet etchant used in microfabrication. It acts as the buffering agent in a solution of concentrated HF, creating an etchant with a more controllable rate of etching (than that of simple concentrated HF solutions).[6]

It is also used for preserving wood, as a mothproofing agent, in printing and dyeing textiles, and as an antiseptic in breweries.[7]

References

[edit]

1. ^ "Ammonium Fluoride". pubchem.ncbi.nlm.nih.gov.
2. ^ "Ammonium Fluoride". pubchem.ncbi.nlm.nih.gov.
3. ^ Bălan, H (January 2012). "Fluoride--the danger that we must avoid" (PDF). Romanian journal of internal medicine = Revue roumaine de medecine interne. 50 (1): 61–9. PMID 22788094. Retrieved 10 December 2025.
4. ^ A. F. Wells, Structural Inorganic Chemistry, 5th ed., Oxford University Press, Oxford, UK, 1984.
5. ^ Brill, R.; Zaromb, S. (1954). "Mixed Crystals of Ice and Ammonium Fluoride". Nature. 173 (4398): 316–317. Bibcode:1954Natur.173..316B. doi:10.1038/173316a0. S2CID 4146351.
6. ^ Wolf, Stanley; Tauber, Richard (1986). Silicon Processing for the VLSI Era: Volume 1 - Process Technology. pp. 532–533. ISBN 978-0-9616721-3-3.
7. ^ Aigueperse, Jean; Paul Mollard; Didier Devilliers; Marius Chemla; Robert Faron; Renée Romano; Jean Pierre Cuer (2005). "Fluorine Compounds, Inorganic". In Ullmann (ed.). Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a11_307. ISBN 3-527-30673-0.

v t e Ammonium salts
Inorganic salts	monatomic anions NH4F (NH4)2S NH4Cl (NH4)2Se NH4Br NH4I oxyanions NH4NO2 NH4NO3 CaNH4PO4 (NH4)2CO3 (NH4)4UO2(CO3)3 (NH4)HCO3 NH4H2AsO4 NH4BrO3 NH4ClO NH4OCN NH4B5O8 (NH4)3PO4 NH4PH2O2 (NH4)2HPO4 (NH4)H2PO4 NH4IO4 (NH4PO4)n(OH)2 NH4NaHPO4 (NH4)2SO3 (NH4)2SO4 (NH4)Al(SO4)2·12H2O (NH4)2Fe(SO4)2·6H2O NH4Fe(SO4)2·12H2O NH4SO3NH2 (NH4)HSO4 (NH4)2S2O8 (NH4)2S2O3 NH4ClO3 NH4ClO4 (NH4)2Mg(SO4)2 NH4VO3 Nd(NH4)2(NO3)5 (NH4)2CrO4 (NH4)2Cr2O7 NH4MnO4 (NH4)3AsO4 NH4BrO4 (NH4)2MoO4 (NH4)6Mo7O24 (NH4)3Mo12PO40 NH4IO3 (NH4)2Ce(NO3)6 (NH4)8Ce2(SO4)8·4H2O (NH4)10H2W12O42·4H2O NH4ReO4 (NH4)2SeO4 (NH4)2TeO4 other anions NH4BF4 NH4N3 NH4CN NH4[Au(CN)2] (NH4)HF2 (NH4)2SeBr6 (NH4)3AlF6 NH4SbF6 NH4AsF6 (NH4)3CrF6 (NH4)3FeF6 (NH4)3GaF6 (NH4)2GeF6 (NH4)3InF6 NH4NbF6 (NH4)2PtF6 (NH4)2ReF6 (NH4)2SnF6 NH4TaF6 (NH4)2UF6 (NH4)3VF6 (NH4)SiF6 (NH4)HS NH4SCN (NH4)2ZnCl4 (NH4)2MoS4 NH4I3 (NH4)2PtBr6 (NH4)2SnBr6 (NH4)2TeCl6 (NH4)2IrCl6 (NH4)2OsCl6 (NH4)2PtCl6 (NH4)2ReCl6 (NH4)2PdCl6 (NH4)2PbCl6 (NH4)3RhCl6 (NH4)2SeCl6 (NH4)2SnCl6 (NH4)4[Fe(CN)6] (NH4)3VS4 (NH4)2S5 (NH4)4[HgBr6] (NH4)2[PtI6] NH4AuCl4 (NH4)2PdCl4 (NH4)3AsS4 (NH4)2WS4 (NH4)2[PtCl4]
Organic salts	Aluminon Ammonium acetate Ammonium adipate Ammonium alginate Ammonium benzoate Ammonium bituminosulfonate Ammonium butyrate Ammonium carbamate Ammonium caprylate Ammonium cinnamate Ammonium citrate Ammonium diethyl dithiophosphate Ammonium ferric citrate Ammonium formate Ammonium fumarate Ammonium glutamate Ammonium heptadecanoate Ammonium itaconate Ammonium lactate Ammonium lauryl sulfate Ammonium laurate Ammonium malate Ammonium malonate Ammonium mandelate Ammonium myristate Ammonium nicotinate Ammonium nonanoate Ammonium oleate Ammonium oxalate Ammonium picrate Ammonium palmitate Ammonium perfluorononanoate Ammonium picolinate Ammonium propionate Ammonium salicylate Ammonium stearate Ammonium succinate Ammonium tartrate Ammonium thioglycolate Ammonium valerate Cupferron Ferric ammonium oxalate Murexide

v t e Fluorine compounds
v t e Salts and covalent derivatives of the fluoride ion HF ?HeF2 LiF BeF2 BFBF3B2F4+BO3 CF4CxFy+CO3 NF3FN3N2F2NFN2F4NF2?NF5+N+NO3 OF2O2F2OFO3F2O4F2?OF4 F2 Ne NaF MgF2 AlFAlF3 SiF4 P2F4PF3PF5+PO4 S2F2SF2S2F4SF3SF4S2F10SF6+SO4 ClFClF3ClF5 ?ArF2?ArF4 KF CaFCaF2 ScF3 TiF2TiF3TiF4 VF2VF3VF4VF5 CrF2CrF3CrF4CrF5?CrF6 MnF2MnF3MnF4?MnF5 FeF2FeF3FeF4 CoF2 CoF3 CoF4 NiF2NiF3NiF4 CuFCuF2?CuF3 ZnF2 GaF2GaF3 GeF2GeF4 AsF3AsF5 Se2F2SeF4SeF6+SeO3 BrFBrF3BrF5 KrF2?KrF4?KrF6 RbF SrFSrF2 YF3 ZrF2ZrF3ZrF4 NbF4NbF5 MoF4MoF5MoF6 TcF4TcF5 TcF6 RuF3RuF4RuF5RuF6 RhF3RhF4RhF5RhF6 PdF2Pd[PdF6]PdF4?PdF6 Ag2FAgFAgF2AgF3 CdF2 InFInF3 SnF2SnF4 SbF3SbF5 TeF4?Te2F10TeF6+TeO3 IFIF3IF5IF7+IO3 XeF2XeF4XeF6?XeF8 CsF BaF2   LuF3 HfF4 TaF5 WF4WF5WF6 ReF4ReF5ReF6ReF7 OsF4OsF5OsF6?OsF7?OsF8 IrF2IrF3IrF4IrF5IrF6 PtF2Pt[PtF6]PtF4PtF5PtF6 AuFAuF3Au2F10?AuF6AuF5•F2 Hg2F2HgF2?HgF4 TlFTlF3 PbF2PbF4 BiF3BiF5 PoF2PoF4PoF6 AtF?AtF3?AtF5 RnF2?RnF4?RnF6 FrF RaF2   LrF3 Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og ↓ LaF3 CeF3CeF4 PrF3 PrF4 NdF2 NdF3 NdF4 PmF3 SmF SmF2 SmF3 EuF2 EuF3 GdF3 TbF3 TbF4 DyF2 DyF3 DyF4 HoF3 ErF3 TmF2 TmF3 YbF2 YbF3 AcF3 ThF2ThF3ThF4 PaF4PaF5 UF3UF4UF5UF6 NpF3NpF4NpF5NpF6 PuF3PuF4PuF5PuF6 AmF2AmF3AmF4?AmF6 CmF3CmF4 ?CmF6 BkF3 BkF4 CfF3 CfF4 EsF3 EsF4?EsF6 Fm MdF3 No
PF−6, AsF−6, SbF−6 compounds	AgPF6 KAsF6 LiAsF6 NaAsF6 HPF6 HSbF6 NH4PF6 LiSbF6 KPF6 KSbF6 LiPF6 NaPF6 NaSbF6 TlPF6
AlF2−5, AlF3−6 compounds	(NH4)3[AlF6] Cs2AlF5 Li3AlF6 K3AlF6 Na3AlF6
chlorides, bromides, iodides and pseudohalogenides	BaClF SiIBrClF BrSO3F Br(SO3F)3 CFN ClFO2 PbFBr PbFCl SrFCl
SiF2−6, GeF2−6 compounds	BaSiF6 BaGeF6 (NH4)2SiF6 Na2[SiF6] K2[SiF6] Li2GeF6 Li2SiF6
Oxyfluorides	AcOF C7H5FO BrOF3 BrO2F ErOF HoOF BrO3F NdOF NpO2F2 LaOF SmOF TbOF ThOF2 VOF3 TcO3F PrOF PuOF PuO2F2 UO2F2 WOF4 C2F4O YOF ClOF3 ClO2F3
Organofluorides	CBrF3 CBr2F2 CBr3F CClF3 CCl2F2 CCl3F CF2O CF3I CHF3 CH2F2 CH3F C2Cl3F3 C2H3F C6H5F C7H5F3 C15F33N C3H5F C6H11F
with transition metal, lanthanide, actinide, ammonium	VOF3 CrOF4 CrF2O2 NH4F (NH4)3CrF6 (NH4)3GaF6 (NH4)2GeF6 (NH4)3FeF6 (NH4)3InF6 NH4NbF6 (NH4)2SnF6 NH4TaF6 (NH4)3VF6 (NH4)2ZrF6 CsXeF7 Li2SnF6 Li2TiF6 LiWF6 Li2ZrF6 K2TiF6 Rb2TiF6 Na2TiF6 Na2ZrF6 K2NbF7 K2TaF7 K2ZrF6 UO2F2
nitric acids	FNO FNO2 FNO3
bifluorides	KHF2 NaHF2 NH4HF2
thionyl, phosphoryl, and iodosyl	FN3O2S F2OS3 F2OS F3OP PSF3 IOF3 IO3F F2O6S2 F2O5S2 FClO5S2 ISO3F IOF5 IO2F IO2F3 I3SO3F S3O8F2
Chemical formulas

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