Selenium disulfide

Selenium disulfide

Names
IUPAC name Selenium disulfide
Other names Selenium sulfide
Identifiers
CAS Number	7488-56-4 Y
ChEMBL	ChEMBL1200680 N
MeSH	Selenium+sulfide
PubChem	24087
RTECS number	VS8925000
InChI InChI=1S/S2Se/c1-3-2
Properties
Chemical formula	SeS2
Molar mass	143.09 g/mol
Appearance	orange to brown powder
Odor	faint
Density	3 g/cm3
Melting point	111 °C (232 °F; 384 K)
Boiling point	118 to 119 °C (244 to 246 °F; 391 to 392 K) (decomposes)
Solubility in water	negligible
Solubility	soluble in ammonium monosulfide negligible in organic solvents
Acidity (pKa)	2-6
Pharmacology
ATC code	D01AE13
Vapor pressure	{{{value}}}
Related compounds
Other anions	Selenium dioxide Selenic acid Selenious acid
Other cations	Hydrogen sulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Selenium disulfide is an inorganic compound with the approximate formula SeS₂. Both sulfur and selenium catenate form chains and rings readily, and mixtures of selenium and sulfur likewise give rise to numerous "alloys". This compound is not an analogue of sulfur dioxide.

It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.

Medical uses

Selenium disulfide is sold as an antifungal agent in shampoos for the treatment of dandruff and seborrheic dermatitis associated in the scalp with Malassezia genus fungi. In the United States, a 1% strength is available over-the-counter, and a 2.5% strength is also available with a prescription. At the 2.5% strength, selenium disulfide is also used on the body to treat tinea versicolor, a type of fungal skin infection caused by a different species of Malassezia.

Chemical composition

Structure of 1,2,3-Se₃S₅

Selenium disulfide has a composition that approximates to SeS₂ and is sometimes called selenium sulfide. However, as used in proprietary formulations, it is not a pure chemical compound but is a mixture where the overall Se:S ratio is 1:2. The compounds are cyclic Se–S rings containing a variable number of S and Se atoms, Se_nS_8−n. Selenium disulfide can cause discoloration of the hair and alter the color of hair dyes. It may also discolor metallic jewellery.

Other selenium sulfides

Many selenium sulfides are known. A useful means for characterization is ⁷⁷Se NMR spectroscopy. Chalcogen ring interconversion pathways. Selenium monosulfide (SeS) is the only selenium compound so far identified as a carcinogen in animals. Selenium monosulfide, along with elemental selenium and sulfur, has been used in medicinal preparations in the past, causing confusion and contradiction as to exactly what form selenium is in any given topical preparation.

See also

• Zinc pyrithione, an antimicrobial agent used in some medicated shampoos
• Selsun Blue, a shampoo with selenium disulfide as its active ingredient
• Ketoconazole, another antifungal agent used in shampoos