Selenium disulfide

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Selenium disulfide
Identifiers
CAS number 7488-56-4 YesY
PubChem 24087
MeSH Selenium+sulfide
ChEMBL CHEMBL1200680 N
RTECS number VS8925000
ATC code D01AE13
Properties
Molecular 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
Hazards
EU Index 034-002-00-8
EU classification Toxic (T)
Dangerous for the environment (N)
R-phrases R23/25, R33, R50/53
S-phrases (S1/2), S20/21, S28, S45, S60, S61
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Other anions Selenium dioxide
Selenic acid
Selenious acid
Other cations Hydrogen sulfide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
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".[1] This compound is not an analogue of sulfur dioxide.

Medicinal selenium disulfide[edit]

The material commercially called 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.[2][3][4] 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[edit]

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, SenS8−n.[1] Selenium disulfide can cause discoloration of the hair and alter the color of hair dyes. It may also discolor metallic jewellery.

Other selenium sulfides[edit]

Many selenium sulfides are known. A useful means for characterization is 77Se NMR spectroscopy. Chalcogen ring interconversion pathways.[5] Selenium monosulfide (SeS) is the only selenium compound so far identified as a carcinogen in animals.[6] Selenium monosulfide, along with elemental selenium and sulfur, has been used in medicinal preparations in the past,[7] causing confusion and contradiction[8] as to exactly what form selenium is in in any given topical preparation.[9]

See also[edit]

References[edit]

  1. ^ a b Cyclic selenium sulfides R. Steudel, R. Laitinen, Topics in Current Chemistry, (1982), 102, 177-197
  2. ^ Selenium(IV) sulfide - pharmacy codes search engine
  3. ^ Chemicals of Selenium .Se
  4. ^ Accessed Dec. 24, 2007
  5. ^ Pekonen, Pentti.; Hiltunen, Yrjō; Laitinen, Risto S.; Pakkanen, Tapani A. (1991). "Chalcogen ring interconversion pathways. 77Se NMR spectroscopic study of the decomposition of 1,2,3,4,5-Se5S2 to 1,2,3,4,5,6-Se6S2 and 1,2,3,4-Se4S2". Inorganic Chemistry 30 (19): 3679. doi:10.1021/ic00019a022. 
  6. ^ "selenium compounds". 
  7. ^ "Definition: selenium sulfide from Online Medical Dictionary". 
  8. ^ "DrugBank: DB00971 (Selenium Sulfide)". 
  9. ^ "selenium sulfide: Definition and Much More from Answers.com". 

Further reading[edit]