Provenance

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

Build a label

Substance profile

Iron (II) sulfate

Iron (II) sulfate is white orthorhombic crystals, hygroscopic.

CAS 7720-78-7 FeO4S 151.91 g/mol Warning

01 · Identification

What Iron (II) sulfate is

Iron (II) sulfate is white orthorhombic crystals, hygroscopic. Its molecular formula is FeO4S and its molecular weight is 151.91 g/mol. It boils at 300 °C, melts at 64 °C, is soluble in water.

Under the GHS it carries the signal word Warning.

CAS number7720-78-7
EC number231-753-5
Index number026-003-00-7
Molecular formulaFeO4S
Molecular weight151.91 g/mol

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 wordWarning
Hazard statements assigned to Iron (II) sulfate
CodeHazard statement
H302 Harmful if swallowed.
H315 Causes skin irritation.
H319 Causes serious eye irritation.

Precautionary statements: P264, P270, P280, P301, P302, P305, P312, P313, P330, P332, P337, P338, P352

03 · Physical and chemical properties

Iron (II) sulfate 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 300 °C (572 °F) above this value DrugBank
Melting point 64 °C (147.2 °F) DrugBank
Density 3.56 g/cm³ HSDB
2.97 g/cm³ at 25 °C HSDB
3.65 g/cm³ at 25 °C DOE PAC
Solubility White to yellow crystalline powder. Sol in water. Loses water @ about 300 °C; decomp @ higher temp. Ferrous sulfate monohydrate HSDB
Soluble in water. HSDB
25.6 g/100 mL DrugBank
Autoignition temperature Not flammable (USCG, 1999) CAMEO

Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.

04 · Handling and storage

Storing and handling Iron (II) sulfate

Storage conditions

Store in tight containers.

Source: Hazardous Substances Data Bank (HSDB)

Incompatible materials

May ignite on contact with arsenic trioxide and sodium nitrate.

Source: Hazardous Substances Data Bank (HSDB)

Reactivity

Weak inorganic reducing agents, such as FERROUS SULFATE, react with oxidizing agents to generate heat and products that may be flammable, combustible, or otherwise reactive.

Source: CAMEO Chemicals

Planning storage for a mix of chemicals? Check Iron (II) sulfate 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.