Zinc ammonium chloride

Zinc ammonium chloride is the inorganic compound with the formula (NH₄)₂ZnCl₄. It is the ammonium salt of tetrachlorozincate. It used as a flux in the process of hot-dip galvanizing.^[1][2][3]

Zinc ammonium chloride

Names
IUPAC name diammonium tetrachlorozincate(2-)
Identifiers
CAS Number	14639-97-5 Y
3D model (JSmol)	Interactive image
ChemSpider	55644
ECHA InfoCard	100.035.155
EC Number	238-687-6
PubChem CID	61754
UNII	NK9T00M5VV Y
UN number	1759
CompTox Dashboard (EPA)	DTXSID90892315 DTXSID6052164, DTXSID90892315
InChI InChI=1S/4ClH.2H3N.Zn/h4*1H;2*1H3;/q;;;;;;+2/p-2 Key: QOQUXKCHSZSKOT-UHFFFAOYSA-L
SMILES [NH4+].[NH4+].Cl[Zn-2](Cl)(Cl)Cl
Properties
Chemical formula	Cl4H8N2Zn
Molar mass	243.26 g·mol−1
Density	1.91 g/cm3
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H314, H315, H400, H411
Precautionary statements	P260, P264, P270, P273, P280, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P332+P313, P362, P363, P391, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Uses

Steel to be galvanized passes through an acidic cleaning process to remove iron oxide "mill scale". After this process, the surface of the steel is very active and oxide layers begin forming immediately upon exposure to the atmosphere. Zinc ammonium chloride flux in aqueous solution is applied to the steel to reduce any oxides that are formed and/or inhibit them from forming altogether. This allows the molten zinc in the proceeding galvanizing step to maximally adhere to and alloy with the surface of the steel.^[4][5]

Precautions

Zinc ammonium chloride is a Class 9 hazardous material (Miscellaneous) according to the U.S. DOT.