| Occurrence and Uses | Iron(II) chloride occurs in nature as the mineral lawrencite. Iron dichloride is used as a mordant for dyeing; and as a reducing agent. It also is used in pharmaceutical preparation; in sewage treatment; and in metallurgy.
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| Physical Properties | White hexagonal crystal; hygroscopic; density 3.16g/cm3; melts at 677°C; vaporizes at 1,023°C; vapor pressure 20 torr at 737°C and 200 torr at 897°C; highly soluble in water, ethanol and acetone; slightly soluble in benzene. The dihydrate and tetrahydrate are greenish monoclinic crystals; densities 2.39 and 1.39 g/cm3, respectively; decomposing at 120 and 105°C, respectively; both the hydrates soluble in water.
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| Preparation | Iron(II) chloride is prepared by passing chlorine or hydrogen chloride gas over iron at red heat or 700°C:
Fe + 2HCl → FeCl2 + H2
Fe + Cl2 → FeCl2
It also may be produced by the reduction of iron(III) chloride with hydrogen or other reducing agents at elevated temperatures:
2FeCl3 + H2 → 2FeCl2 + 2HCl
The tetrahydrate is obtained by dissolving the metal in hydrochloric acid followed by crystallization at room temperature.
Fe + 2HCl + 4H2O → FeCl2•4H2O + H2
The tetrahydrate gradually loses water when heated above 105°C forming dihydrate, monohydrate and the anhydrous salt. At 220°C it loses all its water of crystallization.
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| Chemical Properties | Ferrous chloride is a pale greenish salt-like
crystal or power. |
| Chemical Properties | Greenish-white crystals.
readily oxidized. Soluble in alcohol and water. |
| Physical properties | White hexagonal crystal; hygroscopic; density 3.16g/cm3; melts at 677°C;vaporizes at 1,023°C; vapor pressure 20 torr at 737°C and 200 torr at 897°C;highly soluble in water, ethanol and acetone; slightly soluble in benzene. Thedihydrate and tetrahydrate are greenish monoclinic crystals; densities 2.39and 1.39 g/cm3, respectively; decomposing at 120 and 105°C, respectively;both the hydrates soluble in water. |
| Uses | Used in the synthesis of a novel cis-Fe(BPE5)2Cl2 (BPE5=1,2-diphospholanoethane) complex, which has potential application in many types of reactions such as intra- or intermolecular activation.1 |
| Uses | A paramagnetic solid. |
| Uses | Ferrous chloride (FeCl2) is used in pharmaceutical preparations, for sewage treatment, and
as a mordant (which fixes dyes so that they will not run) in textiles. |
| Preparation | Iron(II) chloride is prepared by passing chlorine or hydrogen chloride gasover iron at red heat or 700°C:
Fe + 2HCl → FeCl2 + H2
Fe + Cl2 → FeCl2
It also may be produced by the reduction of iron(III) chloride with hydrogenor other reducing agents at elevated temperatures:
2FeCl3 + H2 → 2FeCl2 + 2HCl
The tetrahydrate is obtained by dissolving the metal in hydrochloric acidfollowed by crystallization at room temperature.
Fe + 2HCl + 4H2O → FeCl2•4H2O + H2
The tetrahydrate gradually loses water when heated above 105°C formingdihydrate, monohydrate and the anhydrous salt. At 220°C it loses all its waterof crystallization. |
| General Description | Ferrous chloride is a greenish white crystalline solid. Ferrous chloride is soluble in water. Ferrous chloride is noncombustible. Ferrous chloride is used in sewage treatment, in dyeing of fabrics, and for many other uses. |
| Air & Water Reactions | Water soluble. |
| Reactivity Profile | Alkali metal hydroxides, acids, anhydrous chlorides of iron, tin, and aluminum, pure oxides of iron and aluminum, and metallic potassium are some of the catalysts that may cause ethylene oxide to rearrange and polymerize, liberating heat, [J. Soc. Chem. Ind. 68:179(1949)]. Explosions occur , although infrequently, from the combination of ethylene oxide and alcohols or mercaptans, [Chem. Eng. News 20:1318(1942)]. |
| Health Hazard | Inhalation of dust irritates nose and throat. Ingestion causes irritation of mouth and stomach. Dust irritates eyes and may cause skin irritation on prolonged contact. |
| Fire Hazard | Special Hazards of Combustion Products: Irritating hydrogen chloride fumes may form in fire. |
| Flammability and Explosibility | Nonflammable |
| Safety Profile | Poison by ingestion and
intraperitoneal routes. Mutation data
reported. Corrosive. Probably an irritant to
the eyes, skin, and mucous membranes. Can
react violently with ethylene oxide, K, Na.
di%en heated to decomposition it emits
toxic fumes of Cl-. See also CHLORIDES
and IRON. |
| Potential Exposure | It is used in textile dyeing, metallurgy,
the pharmaceutical industry and sewage treatment. |
| Shipping | UN1759 Ferrous chloride, solid, Hazard class: 8;
Labels: 8-Corrosive material. UN1760 Ferrous chloride,
solution, Hazard class: 8; Labels: 8-Corrosive material. |
| Purification Methods | It forms white hygroscopic rhombohedral crystals with a green tint which oxidise in air to FeCl3 and Fe2O3. It is soluble in H2O, EtOH Me2CO but insoluble in Et2O. The tetrahydrate is pale green to pale blue in colour and loses 2H2O at 105-115o. The dihydrate loses H2O at 120o. [Anhydrous FeBr2 can be obtained by carefully dehydrating the tetrahydrate in a stream of HBr and N2, and it can be sublimed under N2.] The ferrous iron in aqueous solutions of these salts readily oxidises to ferric iron. (See above.) [Kovacuumic & Brace Inorg Synth VI 172 1960, Lux in Handbook of Preparative Inorganic Chemistry (Ed Brauer) Academic Press Vol II p 1491 1965.] |
| Incompatibilities | Solution attacks metals. Contact with
ethylene oxide may initiate polymerization. Contact with
potassium or sodium forms an impact-sensitive material. |
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