Substance profile
Zirconium powder (pyrophoric)
Zirconium powder (pyrophoric) is bluish-black, amorphous powder or grayish-white lustrous metal (platelets or flakes) of.
01 · Identification
What Zirconium powder (pyrophoric) is
Zirconium powder (pyrophoric) is bluish-black, amorphous powder or grayish-white lustrous metal (platelets or flakes) of. Its molecular formula is Zr and its molecular weight is 91.22 g/mol. It boils at 4406 °C, melts at 1854 °C, is soluble in water.
Under the GHS it carries the signal word Danger. It is classed as flammable agents - 4th degree.
02 · GHS classification
Hazards and label elements
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
| Code | Hazard statement |
|---|---|
| H250 | Catches fire spontaneously if exposed to air. |
| H260 | In contact with water releases flammable gases which may ignite spontaneously. |
Precautionary statements: P210, P222, P231, P280, P370, P501
03 · Physical and chemical properties
Zirconium powder (pyrophoric) properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 4406 °C (7962.8 °F) | HSDB | |
| 3577 °C (6471 °F) | NIOSH | ||
| 3577 °C (6471 °F) | at 760 mmHg | CAMEO | |
| Melting point | 1854 °C (3369.2 °F) | HSDB | |
| 1857 °C (3375 °F) | NIOSH | ||
| Density | 6.52 g/cm³ | HSDB | |
| 6.51 g/cm³ | Metal | NIOSH | |
| Solubility | Soluble in hot concentrated acid | HSDB | |
| Insoluble | NIOSH | ||
| Insoluble (NIOSH, 2024) | CAMEO | ||
| Vapor pressure | 0 mmHg | HSDB | |
| 0 mmHg | approx | NIOSH | |
| Autoignition temperature | 330 °C (626 °F) | HSDB | |
| Lower explosive limit (LEL) | Sponge zirconium is pyrophoric when pure, and violently explosive when impure. | HSDB | |
| Metal: Combustible, but solid form is difficult to ignite; however, powder form may ignite SPONTANEOUSLY and can continue burning under water. | NIOSH |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Fire and explosion
Fire and explosion behaviour of Zirconium powder…
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
Fire and explosion
Zirconium metal dust is extremely flammable and can cause explosions. It burns with a brilliant flame, forming oxides and nitrides of the metal. Burning zirconium also reacts with halon and carbon dioxide fire-extinguishing agents.
Source: HSDB
Corrosivity
Zirconium is a very reactive metal that, in air or aqueous solution, immediately develops a surface oxide film. This stable, adherent film is the basis for zirconium's corrosion resistance.
Source: HSDB
05 · Handling and storage
Storing and handling Zirconium powder (pyrophoric)
Storage conditions
Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place. Storage class (TRGS 510): Non Combustible Solids.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Incompatible materials: Hydrofluoric acid, fluorine, fluorine nitrate, chlorine, bromine, iodine, halogenated hydrocarbon.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
When a mixture of alkali hydroxides and zirconium is heated, the liberated oxygen reacts explosively with zirconium [Mellor 7:116 1946-47]. Chromates, dichromates, sulfates, molybdates, and tungstates of lithium, sodium, potassium, rubdium, and cesium will react violently, even explosively, with an excess of zirconium powder [Ellern 1968. p. 249]. A mixture of hydrated borax and zirconium explodes when heated [Mellor 7:116 1946-47]. An explosion occurred when zirconium sponge was placed in a beaker of carbon tetrachloride [Allison 1969]. Zirconium explodes violently with cupric oxide or lead oxide [Mellor 7:116 1946-47]. A mixture of powdered zirconium and potassium nitrate explodes when heated above the melting point [Mellor 7:116 1946-47].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Zirconium powder… in the storage compatibility matrix →