Ferric chloride anhydrous

Reported in EPA TSCA Inventory. EPA Genetic Toxicology Program.

OSHA PEL: TWA 1 mg(Fe)/m³
ACGIH TLV: TWA 1 mg(Fe)/m³
DOT Classification:  8; Label: Corrosive

Ferric chloride anhydrous is a chemical compound with the formula FeCl₃. The substance is also called as Iron(III) chloride which is a black crystalline powder. With the CAS register number 7705-08-0, the product is stable but very sensitive to moisture because it is hygroscopic. Ferric chloride anhydrous is incompatible with strong oxidizing agents; forms explosive mixtures with sodium, potassium. This chemical should be stored in a separate safety storage cabinet or room. Ferric chloride anhydrous is toxic to lungs, mucous membranes. It has a relatively low melting point and boils at around 315 °C.

Properties: Ferric chloride anhydrous undergoes hydrolysis to give an acidic solution. Ferric chloride anhydrous is a moderately strong Lewis acid which can form adducts with Lewis bases such as triphenylphosphine oxide, e.g. FeCl₃(OPPh₃)₂. It also can react with chloride salts to produce FeCl^4- ion. Oxalates react rapidly with aqueous Ferric chloride anhydrous to give [Fe(C₂O₄)₃]^3-. It also reacts with iron to convert iron(III) to iron(II). Ferric chloride anhydrous is a mild oxidising agent, for example, it can oxygenize copper(I) chloride to copper(II) chloride. When heated with iron(III) oxide at 350 °C, Ferric chloride anhydrous gives iron oxychloride. The reaction equations are as the following:

2 FeCl₃ + Fe → 3 FeCl₂
FeCl₃ + CuCl → FeCl₂ + CuCl₂
FeCl₃ + Fe₂O₃ → 3 FeOCl

Preparation: Ferric chloride anhydrous can be oxidised with sulfur dioxide to give Ferric chloride anhydrous. In addition, it can also be prepared by union of the elements: iron and chlorine gas.

32 FeCl₂ + 8 SO₂ + 32 HCl → 32 FeCl₃ + S₈ + 16 H₂O
2 Fe(s) + 3 Cl₂(g) → 2 FeCl₃(s)

What's more, Ferric chloride anhydrous can be produced by dissolving iron ore in hydrochloric acid. The reaction equation is as the following:

Fe₃O₄(s) + 8 HCl(aq) → FeCl₂(aq) + 2 FeCl₃(aq) + 4 H₂O

Besides, this chemical can also be prepared by hydrochloric acid and iron powder adding into the reactor to generate ferrous chloride solution. The mixture is defecated and then put into chlorine gas for chlorination reaction to give ferric chloride solution.

Fe + 2 HCl → FeCl₂ + H₂↑
FeCl₂ + Cl₂ → 2 FeCl₃

Uses: Ferric chloride anhydrous can be used as a Lewis acid for catalysing reactions such as chlorination of aromatic compounds and Friedel-Crafts reaction of aromatics in the laboratory. Ferric chloride anhydrous is used to treat sewage and industrial waste. It can also be used to purify water, as an etching agent for engraving circuit boards and in the manufacture of other chemicals. It is also used as a leaching agent in chloride hydrometallurgy, for example in the production of Si from FeSi. In industrial application, Ferric chloride anhydrous is used in sewage treatment and drinking water production.

Another important application of Ferric chloride anhydrous is etching copper to copper(I) chloride and then to copper(II) chloride in the production of printed circuit boards in two-step redox reaction.

FeCl₃ + Cu → FeCl₂ + CuCl
FeCl₃ + CuCl → FeCl₂ + CuCl₂

Ferric chloride anhydrous is used as catalyst for the reaction of ethylene with chlorine, forming ethylene dichloride.

H₂C=CH₂ + Cl₂ → ClCH₂CH₂Cl

What's more, Ferric chloride anhydrous can also be used by knife craftsmen and sword smiths to stain blades, as to give a contrasting effect to the metal, and to view metal layering or imperfections. It is also used in veterinary practice to treat overcropping of an animal's claws, particularly when the overcropping results in bleeding. This chemical can react with cyclopentadienylmagnesium bromide in one preparation of ferrocene, a metal-sandwich complex. It is used in an animal thrombosis model. Besides, it is used in conjunction with NaI in acetonitrile to mildly reduce organic azides to primary amines.

When you are using Ferric chloride anhydrous, you should be very cautious about it. It is harmful if swallowed and irritating to skin. There will be a risk of serious damage to eyes. In case of contact with eyes, you should rinse immediately with plenty of water and seek medical advice. Whenever you will use or contact it, you need wear eye/face protection.

You can still convert the following datas into molecular structure:
(1)Canonical SMILES: Cl[Fe](Cl)Cl
(2)InChI: InChI=1S/3ClH.Fe/h3*1H;/q;;;+3/p-3
(3)InChIKey: RBTARNINKXHZNM-UHFFFAOYSA-K

The toxicity data is as follows:

Organism	Test Type	Route	Reported Dose (Normalized Dose)	Effect	Source
mouse	LD50	intravenous	58mg/kg (58mg/kg)		Yakugaku Zasshi. Journal of Pharmacy. Vol. 87, Pg. 677, 1967.
mouse	LD50	oral	895mg/kg (895mg/kg)		Kenkyu Nenpo--Tokyo-toritsu Eisei Kenkyusho. Annual Report of Tokyo Metropolitan Research Laboratory of Public Health. Vol. 27, Pg. 159, 1976.
rat	LD50	oral	450mg/kg (450mg/kg)		Gigiena i Sanitariya. For English translation, see HYSAAV. Vol. 39(5), Pg. 16, 1974.
women	LDLo	oral	4mL/kg (4mL/kg)	LUNGS, THORAX, OR RESPIRATION: DYSPNEA GASTROINTESTINAL: NAUSEA OR VOMITING	Veterinary and Human Toxicology. Vol. 40, Pg. 31, 1998