Zinc Nitrate
Properties
| State | Solid (colorless, deliquescent crystals; usually as hexahydrate) |
| Color | Colorless to white |
| Solubility | Very soluble in water (327 g/L at 20 °C); soluble in ethanol |
| Melting Point | 110 °C (hexahydrate); 45 °C (anhydrous decomposes) |
| Boiling Point | Decomposes at ~125 °C |
About Zinc Nitrate
Zinc nitrate is a colorless deliquescent salt — Zn(NO3)2, molar mass 189.388 g/mol anhydrous, but the form sitting in a stockroom bottle is almost always the hexahydrate Zn(NO3)2·6H2O at 297.49 g/mol. The hexahydrate melts in its own water of crystallization at about 36 °C, which is why it ends up clumped at the bottom of a warm shipping container in summer. Zinc nitrate is unusual in zinc chemistry because most zinc salts are sparingly soluble — sulfide, hydroxide, carbonate, phosphate — so the nitrate is one of the few high-concentration sources of free Zn2+ in solution. Its other defining feature is the nitrate anion, which is a strong oxidizer when heated and which decomposes the salt cleanly: 2 Zn(NO3)2 -> 2 ZnO + 4 NO2 + O2 at moderate temperatures. That decomposition is now the standard sol-gel and combustion-synthesis route to zinc oxide nanoparticles for sunscreens, transparent conducting films, and gas sensors. In agriculture, Zn(NO3)2 doubles up as a zinc micronutrient and a quick-release nitrogen source for foliar feeds. Analytically, zinc nitrate solutions are the standard for AAS and ICP-MS calibration of Zn.
Where you'll encounter it
If you've ever run a sol-gel synthesis of ZnO nanoparticles in a materials lab, the precursor weighed into the beaker was almost certainly zinc nitrate hexahydrate dissolved in ethanol or 2-methoxyethanol with citric acid as a chelator — the resulting gel calcines at 400-500 °C to give phase-pure wurtzite ZnO with controllable particle size. In a textile finishing plant, Zn(NO3)2 solution is the mordant that fixes certain yellow and brown dyes onto cellulose fibers before the heat-set step. In a winter citrus orchard with zinc-deficient soil, foliar sprays of dilute zinc nitrate are how growers correct the chlorosis and small-fruit symptoms — the nitrate gives a fast nitrogen kick alongside the zinc the trees need for auxin biosynthesis. And in any environmental analysis lab, the zinc spike you add to your ICP-MS calibration curve started life as a 1000 ppm stock from a zinc nitrate solution.
Common Uses
- Sol-gel and combustion-synthesis precursor for ZnO nanoparticles in sunscreens and gas sensors
- Mordant in textile dyeing for fixing yellow and brown azo dyes onto cellulose fibers
- Foliar zinc-plus-nitrogen micronutrient fertilizer for citrus and pecan in zinc-deficient soils
- Catalyst in selected organic syntheses where a soluble oxidizing zinc source is needed
- Analytical 1000 ppm zinc standard stock for AAS and ICP-MS calibration curves
Safety Information
GHS: Oxidizing solid Category 2 (H272), Skin corrosion/irritation Category 2 (H315), Eye irritation Category 2A (H319), Acute toxicity oral Category 4 (H302), Aquatic acute and chronic Category 1 (H400/H410). The oxidizer hazard is the leading concern — never store or mix with paper, sawdust, alcohols, or other combustibles, and never grind in a mortar with organic material. NIOSH REL for nitrate compounds is general particulate (15 mg/m3 total). Wear nitrile gloves and splash goggles, work in a fume hood when calcining (the decomposition releases NO2, OSHA PEL 5 ppm ceiling), and segregate waste from acid and reducing-agent waste streams.
This safety summary is for educational reference only and may not be complete. It is not a substitute for Safety Data Sheets (SDS), medical advice, or professional chemical safety guidance. Always consult appropriate SDS and qualified professionals before handling chemicals.