Selenium disulfide

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Selenium disulfide
Identifiers
CAS number7488-56-4 YesY
PubChem24087
MeSHSelenium+sulfide
ChEMBLCHEMBL1200680 N
RTECS numberVS8925000
ATC codeD01AE13
Jmol-3D imagesImage 1
Properties
Molecular formulaSeS2
Molar mass143.09 g/mol
Appearanceorange to brown powder
Odorfaint
Melting point

-249.5 °C, 24 K, -417 °F

Boiling point

-112 °C, 161 K, -170 °F

Solubility in waternegligible
Solubilitysoluble in ammonium monosulfide
negligible in organic solvents
Acidity (pKa)2-6
Hazards
EU Index034-002-00-8
EU classificationToxic (T)
Dangerous for the environment (N)
R-phrasesR23/25, R33, R50/53
S-phrases(S1/2), S20/21, S28, S45, S60, S61
NFPA 704
NFPA 704.svg
0
2
0
Related compounds
Other anionsSelenium dioxide
Selenic acid
Selenious acid
Other cationsHydrogen sulfide
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
 
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Selenium disulfide
Identifiers
CAS number7488-56-4 YesY
PubChem24087
MeSHSelenium+sulfide
ChEMBLCHEMBL1200680 N
RTECS numberVS8925000
ATC codeD01AE13
Jmol-3D imagesImage 1
Properties
Molecular formulaSeS2
Molar mass143.09 g/mol
Appearanceorange to brown powder
Odorfaint
Melting point

-249.5 °C, 24 K, -417 °F

Boiling point

-112 °C, 161 K, -170 °F

Solubility in waternegligible
Solubilitysoluble in ammonium monosulfide
negligible in organic solvents
Acidity (pKa)2-6
Hazards
EU Index034-002-00-8
EU classificationToxic (T)
Dangerous for the environment (N)
R-phrasesR23/25, R33, R50/53
S-phrases(S1/2), S20/21, S28, S45, S60, S61
NFPA 704
NFPA 704.svg
0
2
0
Related compounds
Other anionsSelenium dioxide
Selenic acid
Selenious acid
Other cationsHydrogen sulfide
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
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.

Contents

Medicinal selenium disulfide

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

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

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

References

  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, Yrjo.; Laitinen, Risto S.; Pakkanen, Tapani A. (1991). "Chalcogen ring interconversion pathways. Selenium-77 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". http://www.scorecard.org/chemical-profiles/html/selenium.html. 
  7. ^ "Definition: selenium sulfide from Online Medical Dictionary". http://cancerweb.ncl.ac.uk/cgi-bin/omd?selenium+sulfide. 
  8. ^ "DrugBank: DB00971 (Selenium Sulfide)". http://redpoll.pharmacy.ualberta.ca/drugbank/cgi-bin/getCard.cgi?CARD=APRD01323.txt. 
  9. ^ "selenium sulfide: Definition and Much More from Answers.com". http://www.answers.com/topic/selenium-sulfide?cat=health. 

Further readings