Iron(II) chloride

  • Ferrous chloride
  • Dichloride
  • Ferrous chloride
  • Ferrum chloratum
  • 7758-94-3
  • 16399-77-2 (dihydrate )
  • 13478-10-9 (tetrahydrate )

B03AA05

White crystals, as the tetrahydrate blue-green, monoclinic, deliquescent crystals

Fixed

3.13 g · cm -3 1.93 g · cm -3

674 ° C 105-110 ° C (release of water of crystallization)

1026 ° C

1.33 hPa ( 700 ° C)

Readily soluble in water: 685 g · l-1 (20 ° C)

Risk

450 mg · kg -1 ( LD50, rat, oral)

Template: Infobox chemical / molecular formula search is not possible

Iron (II ) chloride ( FeCl2 ) is a chemical compound of iron (II) - and chloride ions. Iron (II ) chloride belongs to the group of iron halides. In addition, a crystal water-containing iron ( II) chloride tetrahydrate exists. Iron (II ) chloride tetrahydrate is converted not by heating in anhydrous iron (II ) chloride, as it is decomposed upon heating, and iron ( II) oxide forms.

Under the name of ferric chloride and the iron ( III) chloride precipitates (FeCl3 ).

Occurrence

In nature, iron ( II) chloride is present in form of the mineral Rokühnit ( hydrate).

Production and representation

Iron (II ) chloride can be obtained by reduction of iron (III ) chloride with hydrogen at 300 to 350 ° C ( above that temperature easily occurs, the reduction to iron a ) are displayed.

Iron (II ) chloride can also be prepared by reaction of iron with dry hydrogen chloride gas, less advisable on account of the high temperatures required, this reaction.

On the other hand can not be produced by dissolving iron in hydrochloric acid and subsequent precipitation of anhydrous iron ( II) chloride. This creates the hydrous iron (II ) chloride tetrahydrate FeCl2 · 4 H2O and molecular hydrogen:

Moreover, it is a by- product in the production of titanium dioxide by the chloride process. The pickling of iron sheets and parts, as a preparatory step of the Zinc produces large quantities.

Properties

Iron (II ) chloride is a white, hygroscopic powder, which can be sublimed in the HCl stream at about 700 ° C. The tetrahydrate has a green color which quickly merges with the oxidation by atmospheric oxygen in a brownish color. In water and alcohol are both readily soluble. Iron (II ) chloride has a crystal structure of cadmium (II ) chloride - type with the space group C6mc (a = 357.9 pm, c = 1753.6 pm ).

Use

In the laboratory and in the synthetic chemistry of iron ( II ) chloride is an important starting material for the production of other iron compounds such as iron (III ) chloride.

In wastewater treatment, it serves as precipitants and flocculants. For example, sewage treatment plants often use iron (II ) chloride for phosphate elimination, ie the precipitation of phosphates ( detergent or detergent ingredients ). Best results are achieved with the simultaneous precipitation.

For long sewer lines and sewerage under pressure occurs in the warmer seasons over and over again to odor problems. The reason is the formation of hydrogen sulfide. This form can be used with iron ( II) chloride prevented.

Biogas plants are also struggling with the formation of hydrogen sulfide. This iron ( II) chloride is used for biogas desulphurisation.

In addition to the solid form of iron ( II ) chloride is supplied as an aqueous solution in rubberized tankers or in cans from the chemical trade.

Chlorine CAS registry number Anatomical Therapeutic Chemical Classification System Vapor pressure Dangerous Substances Directive (67/548/EEC) Iron(II) oxide Iron(III) chloride Iron(II) fluoride Iron(II) bromide Iron(II) iodide Iron(III) fluoride Iron(III) bromide
300312
de