Zinc nitrate formula and names
The chemical formula of zinc nitrate is Zn(NO3)2: one zinc ion (Zn2+) balanced by two nitrate ions (NO3−). It is usually sold as the hexahydrate, Zn(NO3)2·6H2O, which carries six molecules of water of crystallisation. The anhydrous salt has a molar mass of 189.4 g/mol and the hexahydrate 297.5 g/mol.
| Item | Anhydrous | Hexahydrate |
|---|---|---|
| Formula | Zn(NO3)2 | Zn(NO3)2·6H2O |
| Molar mass | 189.4 g/mol | 297.5 g/mol |
| CAS number | 7779-88-6 | 10196-18-6 |
| EC number | 231-943-8 | 600-255-3 |
| Zinc content | 34.5% | 22.0% |
Other names include zinc dinitrate and nitric acid zinc salt. The molar mass follows from the atomic masses: 65.38 (zinc) + 2 × [14.007 (nitrogen) + 3 × 15.999 (oxygen)] = 189.39 g/mol; adding 6 × 18.015 for the water gives 297.48 g/mol. Zinc nitrate has no tariff line of its own: it falls under HS 2834.29 with other nitrates (2834.29.51.00 in the US tariff), and it ships as UN 1514.
Appearance and properties
Zinc nitrate is a colourless or white crystalline solid, sold as crystals, powder, flakes or fused pieces. It is extremely soluble in water and absorbs moisture from the air. Values are from the International Chemical Safety Card (ICSC 1206), NOAA’s CAMEO Chemicals database and HSDB.
| Property | Value |
|---|---|
| Appearance | Colourless crystals or white powder; odourless (hexahydrate) |
| Solubility in water | About 200 g per 100 mL at 20 °C (ICSC); 184.3 g per 100 mL for the hexahydrate (HSDB) |
| Other solvents | Very soluble in alcohol |
| pH | 5.1 for a 5% solution of the hexahydrate: slightly acidic |
| Relative density | 2.07 (hexahydrate) |
| Melting point | 36.4 °C (hexahydrate); 45.5 °C (trihydrate) |
| Fire behaviour | Not combustible, but a strong oxidiser that makes other materials burn more fiercely |
The hexahydrate melts at only about 36 °C, so store it somewhere cool. HSDB notes that it loses its water of crystallisation between 105 and 131 °C.
What happens when zinc nitrate is heated
On strong heating, zinc nitrate decomposes to zinc oxide, nitrogen dioxide and oxygen:
2Zn(NO3)2 → 2ZnO + 4NO2 + O2
Zinc oxide is left as a white solid, while nitrogen dioxide is a toxic, red-brown gas. The ICSC warns that heating gives off toxic fumes of nitrogen oxides and zinc oxide, so this should only be done in a fume cupboard.
Grades and water content
Technical zinc nitrate is usually supplied as the hexahydrate, often specified at 98% or more. HSDB notes that it is also sold as fused pieces containing only about 20% water, and as technical flake that usually contains 25.6% water, compared with 36.3% water in the true hexahydrate. Because the water content varies with the form, compare offers on the zinc content and assay printed on the Certificate of Analysis (CoA), not on the product name alone.
How zinc nitrate is made
HSDB describes the method: zinc metal or zinc oxide is dissolved in nitric acid, and the salt crystallises from the solution. With zinc oxide, the reaction is:
ZnO + 2HNO3 → Zn(NO3)2 + H2O
Our guide to nitric acid covers the acid itself.
What zinc nitrate is used for
HSDB and Haz-Map list these industrial uses:
- Textiles: as a mordant in dyeing.
- Catalysts: as a resin catalyst, as an acidic catalyst, and as a catalyst in the manufacture of other chemicals.
- Rubber: as a latex coagulant.
- Fertilisers: as a source of zinc in liquid fertilisers, where its very high solubility is useful.
- Chemistry: as a laboratory reagent and chemical intermediate.
For zinc in solid fertilisers and feed, see also our guide to zinc sulphate.
Hazards, storage and transport
Zinc nitrate is an oxidiser and an irritant. The ICSC gives this UN GHS classification: Danger; may intensify fire (oxidiser); harmful if swallowed; causes skin and eye irritation; may cause respiratory irritation; and very toxic to aquatic life with long-lasting effects. For the anhydrous salt, about 70% of the classifications notified to the European Chemicals Agency also include serious eye damage (H318), so treat eye contact seriously.
- Oxidiser: the ICSC warns that it reacts violently with combustible and reducing materials, and with carbon, copper, metal sulfides, phosphorus and sulfur. Keep it away from these, and from organic materials such as wood, paper and oil.
- Health: it irritates the eyes, skin and respiratory tract. The ICSC lists cough and sore throat, redness and pain of the skin and eyes, and abdominal pain and nausea if swallowed.
- Fire: it does not burn, but it feeds a fire. Use water in large amounts, and keep drums cool with a water spray.
- Environment: it is very toxic to aquatic organisms, with long-term effects, and must not reach drains or waterways.
The ICSC advises preventing dust, using local exhaust or breathing protection, and wearing gloves and safety goggles. For first aid, move the person to fresh air; rinse the skin with plenty of water; rinse eyes for several minutes and get medical attention; and, if swallowed, rinse the mouth and get medical attention. For spills, sweep the material into covered containers and never absorb it in sawdust or other combustible absorbents.
Store zinc nitrate separated from combustible substances and other incompatible materials, in closed containers in a cool place, with provision to contain fire-fighting water. For transport, the ICSC and NOAA give these entries:
| Item | Entry |
|---|---|
| UN number and name | UN 1514, zinc nitrate |
| Hazard class | 5.1 (oxidising substance) |
| Packing group | II |
| US DOT hazard label | Oxidizer |
| Emergency Response Guidebook | Guide 140 (oxidizers) |
| Sea transport | Marine pollutant |
Confirm the classification, packing and labels for your shipment on the current SDS and with your freight forwarder.
Questions to ask a supplier
- Is the product the hexahydrate, flake or fused form, and what are the guaranteed assay and zinc content?
- What are the limits for impurities such as iron, lead and cadmium, if the material is for fertiliser use?
- Can you share a recent Certificate of Analysis and the current SDS for this grade?
- Is the packing approved for UN 1514 (Class 5.1, packing group II) and marked as a marine pollutant?
- How is the packing protected from moisture and heat during transit?
Enquire with Scapex Exports
Scapex Exports is an exporter and supplier of industrial and fine chemicals from India. Our zinc nitrate hexahydrate page lists the grade and packing and links to its COA and MSDS. Related products in our catalogue include zinc oxide, zinc sulphate heptahydrate, zinc acetate dihydrate and nitric acid 68% technical.
Tell us the form, grade, quantity, packing and destination port, and we will reply with a quotation.
Frequently asked questions
What is the formula of zinc nitrate?
Zn(NO3)2. The common commercial form is the hexahydrate, Zn(NO3)2·6H2O. The CAS numbers are 7779-88-6 (anhydrous) and 10196-18-6 (hexahydrate).
What is the molar mass of zinc nitrate?
189.4 g/mol for anhydrous zinc nitrate and 297.5 g/mol for the hexahydrate.
Is zinc nitrate soluble in water?
Yes, extremely: about 200 g dissolves in 100 mL of water at 20 °C. It is also very soluble in alcohol, and a 5% solution of the hexahydrate has a pH of about 5.1.
What happens when zinc nitrate is heated?
It decomposes to zinc oxide, nitrogen dioxide and oxygen: 2Zn(NO3)2 → 2ZnO + 4NO2 + O2. The nitrogen dioxide fumes are toxic.
Is zinc nitrate hazardous?
Yes. It is an oxidiser that can intensify a fire, it is harmful if swallowed, it irritates the skin, eyes and lungs, and it is very toxic to aquatic life. It ships as UN 1514, Class 5.1, packing group II.
Sources: ILO/WHO International Chemical Safety Card ICSC 1206, zinc nitrate; NOAA CAMEO Chemicals datasheet for zinc nitrate; HSDB, Haz-Map and ECHA records for zinc nitrate and its hexahydrate via PubChem; US Harmonized Tariff Schedule, subheading 2834.29.51.