National Biochemicals Corp.
1780 Enterprise Parkway • P.O. Box 1986, Twinsburg, OH 44087, USA
Phone: 330. 425. 2522 • Fax: 330. 425. 2583
www.nationalbiochem.com
FERRIC CHLORIDE
Product No.: MF7134
CAS No.: 7705-08-0
Storage Temperature: Ambient
Synonyms:
Iron(III) Chloride; Iron
Trichloride; Molysite
PRODUCT SPECIFICATIONS
NOMENCLATURE
Molecular Formula:
FeCl3
Molecular Weight:
162.2
Appearance:Y e l l o w - B r o w n
Deliquescent Crystals
Solubility (3 g in 10 mL Water):Complete,
Clear,
B r o w n i s h - R e d ,
Haze-Free
Assay (Min.):98.0%
Ferrous Chloride (Max.):
1.0%
Insoluble Matter (Max.):
2.0%
IR Scan:
Conforms to Reference
The descriptor hydrated or anhydrous is used when referring
to Ferric Chloride, to distinguish between the two common
forms. The hexahydrate is usually given as the simplified
empirical formula FeCl3 • 6H2O. It may also be given as
trans-[Fe(H2O)4Cl2]Cl • 2H2O and the systematic name
tetraaquadichloroiron(III) chloride dihydrate, which more
clearly represents its structure.
PRODUCT DESCRIPTION
Ferric Chloride, also called Iron(III) Chloride, is an industrial
scale commodity chemical compound. The color of Ferric
Chloride crystals depends on the viewing angle; by reflected
light, the crystals appear dark green, but by transmitted
light they appear purple-red. Anhydrous Ferric Chloride is
deliquescent, forming hydrated hydrogen chloride mists in
moist air. It is rarely observed in its natural form, mineral
molysite, known mainly from some fumaroles.
When dissolved in water, Ferric Chloride undergoes
hydrolysis and gives off heat in an exothermic reaction. The
resulting brown, acidic, and corrosive solution is used as a
flocculant in sewage treatment and drinking water production,
and as an etchant for copper-based metals in printed circuit
boards. Anhydrous Ferric Chloride is a fairly strong Lewis
acid, and it is used as a catalyst in organic synthesis.
STRUCTURE & PROPERTIES
Anhydrous Ferric Chloride adopts the Bil3 structure, which
features octahedral Fe(III) centres interconnected by twocoordinate chloride ligands. Ferric Chloride hexahydrate
consists of trans-[Fe(H2O)4Cl2]+ cationic complexes and
chloride anions, with the remaining two H2O molecules
embedded within the monoclinic crystal structure.5
Ferric Chloride has a relatively low melting point and boils
at around 315°C. The vapor consists of the dimer Fe2Cl6 which
increasingly dissociates into the monomeric FeCl3 at higher
temperature, in completion with its reversible decomposition
to give Ferric Chloride and chlorine gas.6
PREPARATION
Anhydrous Ferric Chloride may be prepared by union of the
elements:7
2Fe(s) + 3Cl2(g) → 2FeCl3(s)
Solutions of Ferric Chloride are produced industrially both
from iron and from ore, in a closed-loop process.
1. Dissolving pure iron in a solution of Ferric Chloride
Fe(s)
+
2FeCl3(aq)
→
3FeCl2(aq)
2. Dissolving
iron
ore
in
hydrochloric
acid
Fe3O4(s) + 8HCl(aq) → FeCl2(aq) + 2FeCl3(aq) + 4H2O
page 1
3. Oxidation
2FeCl2(aq)
of
+
Ferric Chloride with chlorine
Cl2(g)
→
2FeCl3(aq)
4. Oxidation of Ferric Chloride with oxygen
FeCl2(aq) + ¼O2 + HCl → FeCl3(aq) + ½H2O
Like many other hydrated metal chlorides, Ferric Chloride
can be converted to the anhydrous salt by refluxing with
thionyl choride.8 Conversion of the hydrate to anhydrous
Ferric Chloride is not accomplished by heating, as HCl and
iron oxychlorides are produced.
USES
Industrial
In industrial applications, Ferric Chloride is used in sewage
treatment and drinking water production.13 In this application,
FeCl3 in slightly basic water, reacts with the hydroxide
ion to forma floc of iron(III) hydroxide, or more precisely
formulated as FeO(OH)-, that can remove suspended materials.
[Fe(H2O)6]3+ + 4HO- → [Fe(H2O)2(HO)4]- + 4H2O → [Fe(H2O)O(HO)2]- + 6H2O
REACTIONS
It is also used as a leaching agent in chloride hydrometallurgy,14
for example, in the production of Si from FeSi.15
Ferric Chloride undergoes hydrolysis to give an acidic
solution. When heated with iron(III) oxide at 350°C,
Ferric Chloride gives iron oxychloride, a layered solid
intercalation host.
Another important application of Ferric Chloride is etching
copper in two-step redox reaction to copper(I) chloride
and then to copper(II) chloride in the production of printed
circuit boards.16
FeCl3 + Fe2O3 → 3FeOCl
FeCl3 + Cu → FeCl2 + CuCl
FeCl3 + CuCl → FeCl2 + CuCl2
It is a moderately strong Lewis acid, forming adducts
with Lewis bases such as triphenylphosphine oxide, e.g.
FeCl3(OPPh3)2 where pH = phenyl. It also reacts with other
chloride salts to give a yellow tetrahedral FeCl4- ion. Salts of
FeCl4- in hydrochloric acid can be extracted into diethyl ether.
Alkali metal alkoxides react to give the metal alkoxide
complexes of varying complexity.9 The compounds can
be dimeric or trimeric.10 In the solid phase a variety of
multinuclear complexes have been described for the nominal
stoichiometric reaction between FeCl3 and sodium ethoxide:11,12
FeCl3 + 3[C2H5O]-Na+ → Fe(OC2H5)3 + 3NaCl
Oxalates react rapidly with aqueous Ferric Chloride to give
[Fe(C2O4)3]3-. Other carboxylate salts form complexes, e.g.
citrate and tartrate.
Ferric Chloride is used as catalyst for the reaction of ethylene
with chlorine, forming ethylene dichloride, an important
commodity chemical, which is mainly used for the industrial
production of vinyl chloride, the monomer for making PVC.
H2C=CH2 + Cl2 → ClCH2CH2Cl
Laboratory
In the laboratory, Ferric Chloride is commonly employed
as a Lewis Acid for catalyzing reactions such as chlorination
of aromatic compounds and Friedel-Crafts Reaction of
aromatics. It is less powerful than aluminum chloride, but in
some cases this mildness leads to higher yields, for example
in the alkylation of benzene:
FeCl3
Oxidation
Ferric Chloride is a mild oxidizing agent, for example, it is
capable of oxidizing copper(I) chloride to copper(II) chloride.
FeCl3 + CuCl → FeCl2 + CuCl2
It also reacts with iron to form iron(II) chloride:
2FeCl3 + Fe → 3FeCl2
Reducing agents such as hydrazine convert Ferric Chloride
to complezes of iron(II).
Cl
excess
83% yield
The Ferric Chloride test is a traditional colorimetric test for
phenols, which uses a 1% iron(III)chloride solution that has been
neutralized with sodium hydroxide until a sight precipitate of
FeO(OH) is formed.17 The mixture is filtered before use. The
organic substance is dissolved in water, methanol or ethanol,
then the neutralized Ferric Chloride solution is added - a
transient or permanent coloration indicates the presence of a
phenol or enol.
This reaction is exploited in the Trinder Spot Test, which
is used to indicate the presence of salicylates, particularly
salicylic acid, which contains a phenolic OH group.
page 2
Other Uses
• Used
drying
in
anhydrous
reagent
in
form
certain
as
a
reactions.
•
Used to detect
compounds
in
examining
purity
the presence of phenol
organic
synthesis,
e.g.
of
synthesized
Aspirin.
•
Used in water and wastewater treatment to
precipitate phosphate as iron(III) phosphate.
•
Used by American coin collectors to identify
the dates of Buffalo Nickels that are so badly
worn that the date is no longer visible.
•
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.
•
Used to etch the widmanstatten pattern in iron meteorites.
•
Necessary
plates for
images in
cylinders
to
for the etching of photogravure
printing photographic and fine art
intaglio and for etching rotogravure
used
in
the
printing
industry.
•
Used
make
printed
circuit
boards.
•
Used
in
veterinary
practice
to
treat
overcropping of an animal’s claws, particularly
when the overcropping results in bleeding.
PRECAUTIONS & DISCLAIMER
This product is solely for Research and Development use.
It is not for drug, household, or any other uses. Please
review the Safety Data Sheet for information regarding
risks and safe handling practices.
REFERENCES
1. Pradyot, P., Handbook of Inorganic Chemicals, (2002).
2. w w w . e r m a n z . g o v t . n z / C h e m i c a l s /
C h e m i c a l D i s p l a y. a s p x ? S u b s t a n c e I D = 1 0 7 6 4 .
3. Various Suppliers, Collated by the Baylor College
of Dentistry, Texas A&M University, (2010).
4. GHS
Classification,
Japanese
Inter-ministerial
Committee,
GHS
(2006).
5. Lind, M.D., Crystal Structure of Ferric Chloride
Hexahydrate, J. Chem. Phys., 47: 990, (1967).
6. Holleman, A.F., Wiberg, E., Inorganic Chemistry, (2001).
7. Tarr, B.R., Booth, H.S., Dolance, A., Anhydrous
Iron
(III)
Chloride,
Inorganic
Synthesis,
Inorganic Synthesis, 3: 191 - 194, (1950).
8. Pray, A.R., Heitmiller, R.F., Strycker, S., Anhydrous Metal
Chlorides, Inorganic Synthesis, 28: 321 - 323, (1990).
•
Reacts with cyclopentidienylmagnesium bromide in one
preparation of ferrocene, a metal-sandwich complex.18
9. The
Ya
•
Sometimes used in a technique of Raku ware firing, the iron
coloring a pottery piece shades of pink, brown and orange.
10. Alkoxo and Aryloxo Derivatives of Metals by
D.C. Bradley, Alkoxides of later 3D metals, p. 69.
•
Used to test the pitting and crevice corrosion
resistance of stainless steels and other alloys.
•
Used in conjunction with Nal in acetonitrile to
mildly reduce organic azides to primary amines.19
11. Veith, M., Grätz, F., Huch, V., Fe9O3(OC2H5)21 •
C2H5OH - A new structure Type of an Uncharged
Iron(III) Oxide-Alkoxide Cluster, European J.
of Inorg. Chem., Vol. 2001, Issue 2, p. 367 - 368.
•
Used
in
an
animal
thrombosis
model.20
SAFETY
Ferric Chloride is toxic, highly corrosive and acidic. The
anhydrous material is a powerful dehydrating agent. Although
reports of poisoning in humans are rare, ingestion of Ferric
Chloride can result in serious morbidity and mortality.
Inappropriate labeling and storage lead to accidental
swallowing or misdiagnosis. Early diagnosis is important,
especially in seriously poisoned patients.
chemistry
of
metal
Turova,
N.,
Synthesis,
alkoxides,
p.
481.
12. Seisenbaevaa, G.A., Gohila, S., Suslovab, E.V.,
Rogovab, T.V., Turovab, N.Y., Kesslera, V.G.,
The synthesis of iron(III) ethoxide revisted:
Characterization of the metathesis products of iron(III)
halides and sodium ethoxide, Inorganica Chimica
Acta, Volume 358, Issue 12, p. 3506 - 3512, (2005).
13. w w w . a k z o n o b e l . c o m / i c / s y s t e m / i m a g e s /
AkzoNobel_WTCBrochureENG_tcm18-9982.pdf.
14. Separation
Technology,
51:
and
332
15. Chem.
Sci.,
61:
page 3
Eng.
229
337,
-
Purification
(2006).
245,
(2006).
16. Greenwood,
Chemistry of
N.N.,
Earnshaw,
the Elements, 2nd ed.,
17. Furnell, B.S., et al., Vogel’s
Practical Organic Chemistry, 5th
A.,
(1997).
Textbook of
ed., (1989).
18. Kealy, T.J., Pauson, P.L., A new type of Organoiron compound, Nature, 168(4285): 1040, (1951).
19. Kamal, A., Ramana, K., Ankati, H., Ramana,
A., Mild and efficient reduction of azides to
amines: synthesis of fused [2,1-b]quinazolines,
Tetrahedron
Letters,
43(38):
6961,
(2002).
20. Tseng, M., Dozier, A., Haribabu, B., Graham,
U.M.,Transendothelial migration of ferric ion
in FeCl3 injured murine common carotid artery,
Thrombosis Research, 118(2): 275 - 280, (2006).
NBC warrants that its products will conform with the information provided in this information sheet, though the Purchaser must
determine the suitability of the products for their particular usage needs. Additional terms and conditions may apply.
page 4
MF7134 • 08/08/13 • Rev. 1