Zinc chloride
[CAS# 7646-85-7]

Identification

• Classification: API >> Vitamins and minerals >> Trace elements and mineral drugs
• Name: Zinc chloride
• Synonyms: dichlorozinc
• Molecular Formula: ZnCl₂
• Molecular Weight: 136.30
• CAS Registry Number: 7646-85-7
• EC Number: 231-592-0
• SMILES: Cl[Zn]Cl

Properties

• Density: 2.91
• Melting point: 293 °C
• Boiling point: 732 °C
• Water solubility: 432 g/100 mL (25 °C)

Safety Data

• Hazard Symbols: GHS05;GHS07;GHS09 Danger
• Risk Statements: H302-H314-H400-H410
• Safety Statements: S26;S36/37/39;S45;S60;S61

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	4	H302
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Serious eye damage	Eye Dam.	1	H318
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Acute toxicity	Acute Tox.	3	H301
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Flammable liquids	Flam. Liq.	2	H225
Skin corrosion	Skin Corr.	1A	H314
Skin corrosion	Skin Corr.	1	H314
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Skin sensitization	Skin Sens.	1	H317

• Transport Information: UN 2331

Discovery and Applications

Zinc chloride, with the chemical formula ZnCl₂, is a versatile compound that was first discovered and isolated in the early 19th century. It is prepared by treating zinc oxide or zinc metal with hydrochloric acid to produce zinc chloride and water, or by heating zinc with chlorine gas. Originally used in textile processing and metallurgical applications, its versatility quickly expanded to many other industries. Zinc chloride is typically a white crystalline solid that is highly soluble in water and alcohol.

Zinc chloride is essential in the galvanizing process, where it prepares metal surfaces, especially steel, for zinc plating by removing oxides and providing a clean surface for adhesion. It acts as a catalyst and Lewis acid in a variety of chemical reactions, including organic synthesis, dyeing processes, and petroleum refining. Zinc chloride is used as a wood preservative to prevent decay and fungal growth, extending the life of wood products.

In dentistry, zinc chloride solutions are used in dental fillings and mouthwashes for their astringent and antimicrobial properties. It is added to topical antimicrobial solutions and ointments for skin disinfection and wound treatment.

Zinc chloride electrolytes are used in certain types of batteries, including zinc-carbon batteries, because of their conductivity and stability. In soldering and welding applications, zinc chloride acts as a flux, promoting solder flow and removing metal oxides from joint surfaces. It is used as a mordant and dye fixative in textile dyeing and printing processes.

Zinc chloride is safe when used properly, but direct contact can cause skin and eye irritation. Proper ventilation and personal protective equipment (PPE) should be used during handling to prevent inhalation or ingestion, and it is toxic if swallowed.

Research continues to explore new applications and improved formulations for zinc chloride in various industries. Advances in nanotechnology and materials science may enhance its use in electronics, catalysis, and environmental remediation.

References

2000. Total synthesis of a demethoxy-egonol from Styrax obassia. Archives of Pharmacal Research, 23(10).
DOI: 10.1007/bf02976567

1998. Protective effects of zinc on cadmium toxicity in rodents. Biological Trace Element Research, 75(1-3)
DOI: 10.1007/bf02784291

1997. Zinc depletion suppresses tumor growth in mice. Biological Trace Element Research, 59(12)
DOI: 10.1007/bf02783226