Silver iodide Chemical Properties

Melting point:

557°C

Boiling point:

1506°C

Density 

5.68 g/mL at 25 °C (lit.)

RTECS 

VW4450000

solubility 

insoluble in acid solutions

form 

Solid

Specific Gravity

6.01

color 

Yellow

Odor

odorless

Water Solubility 

0.03 mg/L

Sensitive 

Light Sensitive

Crystal Structure

Cubic, Sphalerite Structure - Space Group F(-4)3m

Merck 

14,8516

Solubility Product Constant (Ksp)

pKsp: 16.07

Exposure limits

ACGIH: TWA 0.01 ppm

Stability:

Stability Light-sensitive. Incompatible with strong oxidizing agents.

CAS DataBase Reference

7783-96-2(CAS DataBase Reference)

NIST Chemistry Reference

Silver iodide(7783-96-2)

EPA Substance Registry System

Silver iodide (AgI) (7783-96-2)

Safety Information

Risk Statements 

36/37/38-53

Safety Statements 

22-24/25

RIDADR 

UN 3077 9 / PGIII

WGK Germany 

3

F 

8

TSCA 

Yes

HazardClass 

9

HS Code 

28432900

Hazardous Substances Data

7783-96-2(Hazardous Substances Data)

MSDS

• Language:English Provider:Silver iodide
• Language:English Provider:SigmaAldrich
• Language:English Provider:ACROS
• Language:English Provider:ALFA

Silver iodide Usage And Synthesis

Description

Silver iodide (AgI) precipitates as a yellow, odor- and tasteless solid. Silver iodide acts as a very effective nucleus for the formation of ice crystals. Silver iodide has an important advantage over mercury as a subject for study of electrochemical properties of interfaces. It is also used as a solid lubricant for power contacts. It is also used as a local antiseptic.

References

[1] B. Vonnegut, The Nucleation of Ice Formation by Silver Iodide, Journal of Applied Physics, 1947, vol. 18, 593
[2] J. Lyklema and J. Th. G. Overbeek, Electrochemistry of silver iodide the capacity of the double layer at the silver iodide-water interface, Journal of Colloid Science, 1961, col. 16, 595-608
[3] Sylva Arnell and Gunnar Andersson, Silver Iodide as a Solid Lubricant for Power Contacts,  Proceedings of the Forty-Seventh IEEE Holm Conference on Electrical Contacts, 2001

Chemical Properties

Yellow Crystalline Powder

Physical properties

Light yellow hexagonal crystals or powder; darkens on exposure to light; density 5.68 g/cm³ ; melts at 558°C; vaporizes at 1,506°C; insoluble in water, most acids and ammonium carbonate solution; moderately soluble in concentrated solutions of alkali chloride, bromide, and thiosulfate; readily soluble in solutions of alkali cyanides, iodides and in hot concentrated hydriodic acid.

Uses

In cloud precipitation (rain-making).

Uses

Silver iodide is a yellow powder formed by the combination of a soluble iodide combined with silver nitrate. Silver iodide could also be formed by exposing metallic silver to the fumes of bromine as in the daguerreotype process. This was the primary halide used for all of the 19th century camera processes until the introduction of the silver bromide gelatin plate. With the exception of the daguerreotype, all silver iodide processes relied on physical development using a reducing agent such as gallic acid, pyrogallic acid, or ferrous sulfate, an acid restrainer, and excess silver.

Uses

Used in medicine for its caustic, astringent and antiseptic effects. Used in photography, and in the estimation of silver. Through heterogeneous nucleation, it is used in cloud seeding, relying on its beta-AgI crystal structure being similar to that of Ice.

Definition

T3DB: Silver iodide is an iodide of silver. It is a photosensitive solid used in photography, as an antiseptic in medicine, and in rainmaking. Silver is a metallic element with the chemical symbol Ag and atomic number 47. It occurs naturally in its pure, free form, as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite.

Preparation

Silver iodide is prepared by adding a solution of sodium or potassium iodide to a hot solution of silver nitrate: Ag+ (aq) + Iˉ (aq) → Ag I (s) The precipitate is washed with boiling water. The preparation is done in the dark under ruby red light.

Hazard

Silver iodide may cause irritation and psoriasis, and the main hazards encountered in the use and handling of silver iodide arise from its toxicological properties. It is toxic by a variety of routes (i.e. inhalation, ingestion and dermal contact) and exposures may include rashes, conjunctivitis, psoriasis (permanent greyish-grey discolouration of the skin, conjunctiva, and internal organs), headache, fever, hypersensitivity reactions, laryngitis and bronchitis.

Health effects

Silver itself is not toxic to humans, but most silver salts are. In large doses, silver and compounds containing it can be absorbed into the circulatory system and become deposited in various body tissues, leading to argyria, which results in a blue-grayish pigmentation of the skin, eyes, and mucous membranes. Argyria is rare, and although, so far as known, this condition does not otherwise harm a person's health, it is disfiguring and usually permanent. Mild forms of argyria are sometimes mistaken for cyanosis.

Flammability and Explosibility

Non flammable

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