Silver chloride

Silver chloride is a chemical compound with the chemical formula AgCl. This white
crystalline solid is well known for its low solubility in water (this behavior being
reminiscent of the chlorides of Tl+ and Pb2+). Upon illumination or heating, silver
chloride converts to silver (and chlorine), which is signaled by grey to black or
purplish coloration to some samples. AgCl occurs naturally as a mineral chlorargyrite.

Silver chloride

Names

IUPAC name

Silver chloride

Other names
cerargyrite
chlorargyrite
horn silver

Identifiers

CAS Number ▪ 7783-90-6

3D model (JSmol) ▪ Interactive image

ChEBI ▪ CHEBI:30341

ChemSpider ▪ 22967

ECHA InfoCard 100.029.121

PubChem CID ▪ 24561

RTECS number ▪ VW3563000

UNII ▪ MWB0804EO7

CompTox ▪ DTXSID4035251
Dashboard (EPA)

InChI

SMILES

Properties
Chemical formula AgCl

Molar mass 143.32 g·mol−1

Appearance White Solid

Density 5.56 g cm−3

Melting point 455 °C (851 °F; 728 K)

Boiling point 1,547 °C (2,817 °F; 1,820 K)

Solubility in water 520 μg/100 g at 50 °C

Solubility soluble in NH3, conc. HCl,

conc. H2SO4, alkali
cyanide, NH4CO3?, KBr, Na2S2O3;

insoluble in alcohol, dilute

acids.
Magnetic −49.0·10−6 cm3/mol
susceptibility (χ)
Refractive index 2.071
(nD)

Structure
Crystal structure halite

Thermochemistry
Std molar 96 J·mol−1·K−1
entropy (So298)
Std enthalpy of −127 kJ·mol−1
formation (ΔfH⦵298)

Hazards

Safety data sheet Fischer Scientific, Salt Lake

Metals

NFPA
704 (fire diamond)

0
2
0
Related compounds
Other anions silver(I) fluoride, silver
bromide, silver iodide
 Except where otherwise noted, data are given for
materials in their standard state (at 25 °C [77 °F],
100 kPa).

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Infobox references

Preparation
Silver chloride is easily synthesized by combining aqueous solutions of silver
nitrate and sodium chloride.

It can also be produced by reacting silver nitrate with cobalt(II) chloride. This
precipitation is general for silver nitrate's reaction with soluble chloride salts and is
not unique simply to cobalt.

Structure and reactions

Silver chloride crystals

Pyramidal crystals of AgCl

The solid adopts the fcc NaCl structure, in which each Ag+ ion is surrounded by an
octahedron of six chloride ligands. AgF and AgBr crystallize similarly. However, the
crystallography depends on the condition of crystallization, primarily free silver ion
concentration, as is shown on the pictures left (greyish tint and metallic lustre are due
to partly reduced silver). AgCl dissolves in solutions containing ligands such as
chloride, cyanide, triphenylphosphine, thiosulfate, thiocyanate and ammonia. Silver
chloride reacts with these ligands according to the following illustrative equations:

Silver chloride does not react with nitric acid. Most complexes derived from AgCl are
two-, three-, and, in rare cases, four-coordinate, adopting linear, trigonal planar, and
tetrahedral coordination geometries, respectively.

Above 2 reactions are particularly important in qualitative analysis of AgCl in labs as

AgCl is white in colour , which changes to (silver arsenite) which is yellow in

colour or (Silver arsenate) which is reddish brown in colour.

Chemistry

Silver chloride decomposes over time with exposure to UV light

In one of the most famous reactions in chemistry, addition of colorless aqueous silver
nitrate to an equally colorless solution of sodium chloride produces an opaque white
precipitate of AgCl:

This conversion is a common test for the presence of chloride in solution. Due to its
conspicuousness it is easily used in titration, which gives the typical case of
argentometry.
The solubility product, Ksp, for AgCl in water is 1.77×10−10 at room temperature, which

indicates that only 1.9 mg (that is, ) of AgCl will dissolve per liter of water. The
chloride content of an aqueous solution can be determined quantitatively by weighing
the precipitated AgCl, which conveniently is non-hygroscopic, since AgCl is one of the
few transition metal chlorides that is unreactive toward water. Interfering ions for
this test are bromide and iodide, as well as a variety of ligands (see silver halide). For
AgBr and AgI, the Ksp values are 5.2 x 10−13 and 8.3 x 10−17, respectively. Silver
bromide (slightly yellowish white) and silver iodide (bright yellow) are also
significantly more photosensitive than is AgCl.
AgCl quickly darkens on exposure to light by disintegrating into
elemental chlorine and metallic silver. This reaction is used in photography and film.
Uses
▪ The silver chloride electrode is a common reference electrode in
electrochemistry.
▪ Silver chloride's low solubility makes it a useful addition to pottery glazes for
the production of "Inglaze lustre".
▪ Silver chloride has been used as an antidote for mercury poisoning, assisting in
the elimination of mercury.
▪ Silver chloride is used:
• to make photographic paper since it reacts with photons to form latent
image and via photoreduction
• in photochromic lenses, again taking advantage of its reversible
conversion to Ag metal
• in bandages and wound healing products

• to create yellow, amber, and brown shades in stained glass manufacture

• as an infrared transmissive optical component as it can be hot-pressed

into window and lens shapes
• as an antimicrobial agent:
o in some personal deodorant products

o for long-term preservation of drinking water in water tanks

References
1. Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company.
p. A23. ISBN 978-0-618-94690-7.
2. Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-
19-855370-6.
3. More info on Chlorine test Archived December 3, 2007, at the Wayback Machine
4. "Silver Chloride (AgCl) Optical Material". www.crystran.co.uk. Archived from the original
on September 5, 2012. Retrieved 2019-12-04.