Characteristic

Iron(II) chloride, also known as ferrous chloride, is the chemical compound of formula FeCl₂. It is a paramagnetic solid with a high melting point.

Chemical formula：FeCl₂

Molar mass：126.751 g/mol (anhydrous)

                       198.8102 g/mol (tetrahydrate)

Appearance：Tan solid (anhydrous)

                       Pale green solid (di-tetrahydrate)

Density：3.16 g/cm³ (anhydrous)

                2.39 g/cm³ (dihydrate)

                1.93 g/cm³ (tetrahydrate)

Melting point：677 °C (1,251 °F; 950 K) (anhydrous)

                         120 °C (dihydrate)

                         105 °C (tetrahydrate)

Boiling point：1,023 °C (1,873 °F; 1,296 K) (anhydrous)

Solubility in water：64.4 g/100 mL (10 °C),

                                68.5 g/100 mL (20 °C),

                                105.7 g/100 mL (100 °C)

Solubility in THF：Soluble

log P：−0.15

Magnetic susceptibility (χ)：+14750·10⁻⁶ cm³/mol

Crystal structure：Monoclinic

Application

Unlike the related ferrous sulfate and ferric chloride, ferrous chloride has few commercial applications. Aside from use in the laboratory synthesis of iron complexes, ferrous chloride serves as a coagulation and flocculation agent in wastewater treatment, especially for wastes containing chromate or sulfides. It is used for odor control in wastewater treatment. It is used as a precursor to make various grades of hematite that can be used in a variety of pigments. It is the precursor to hydrated iron(III) oxides that are magnetic pigments. FeCl₂ finds some use as a reagent in organic synthesis.