Provenance

Reference data from EU CLP Annex VI and published regulations — verify against your supplier's SDS before use.

Build a label

Substance profile

Mercury cyanide oxide (Hg2(CN)2O)

Mercury cyanide oxide (Hg2(CN)2O) is a chemical substance with the molecular formula C2Hg2N2O.

CAS 1335-31-5 C2Hg2N2O 469.22 g/mol Danger

01 · Identification

What Mercury cyanide oxide… is

Mercury cyanide oxide (Hg2(CN)2O) is a chemical substance with the molecular formula C2Hg2N2O. Its molecular formula is C2Hg2N2O and its molecular weight is 469.22 g/mol.

Under the GHS it carries the signal word Danger.

CAS number1335-31-5
EC number215-629-8
Index number080-006-00-8
Molecular formulaC2Hg2N2O
Molecular weight469.22 g/mol

Other names for Mercury cyanide oxide…

  • dimercury dicyanide oxide
  • mercuric oxycyanide

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.

Signal wordDanger
Hazard statements assigned to Mercury cyanide oxide…
CodeHazard statement
H201 Explosive; mass explosion hazard.
H331 Toxic if inhaled.
H311 Toxic in contact with skin.
H301 Toxic if swallowed.
H373 May cause damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
H400 Very toxic to aquatic life.
H410 Very toxic to aquatic life with long lasting effects.

Precautionary statements: P210, P260, P270, P271, P273, P280, P301, P302, P304, P310, P314, P330, P352, P391, P501

03 · Handling and storage

Storing and handling Mercury cyanide oxide…

Reactivity

MERCURIC OXYCYANIDE detonates on heating [Hawley]. Several instances have been reported where explosions occurred in handling this substance. Friction is a frequent cause of the explosion [Chem. Abst. 16:2010. 1972]. Decomposes on contact with acid to give off hydrogen cyanide, a flammable poisonous gas. Desensitized by mixing 67% mercuric cyanide to create commercial product.

Source: CAMEO Chemicals

Planning storage for a mix of chemicals? Check Mercury cyanide oxide… in the storage compatibility matrix →

Get the free GHS / CLP / OSHA deadline calendar

Verified 2026–2029 compliance dates in one PDF — plus alerts when the rules change.