Selenium sulfide

Structure of 1,2,3-Se ₃ S ₅

The compounds of sulfur and selenium are called selenium sulfides . However, after production via the usual synthesis routes , the individual compounds are present as a mixture of substances , which is often also called selenium disulfide due to the average ratio formula .

properties

safety instructions
Surname	Selenium disulfide
CAS number	7488-56-4
GHS labeling of hazardous substances danger H and P phrases H: 301-331-373-410 P: 261-273-301 + 310-311-501

The mixture of selenium sulfides consists of eight-membered rings with a variable composition (Se _n S _{8 − n} ).

Due to the typical composition of the mixture with the ratio formula SeS ₂ , the term selenium disulfide is often used . It is a light orange to reddish brown powder that is insoluble in water and has a melting point of <100 ° C. When exposed to acids , poisonous hydrogen sulfide vapors are produced.

The compounds are also used in pharmaceutical formulations as a mixture.

Manufacturing

The selenium sulfides can be produced directly from the elements selenium and sulfur:

${\displaystyle \mathrm {Se+2\ S\longrightarrow \ SeS_{2}} }$

They are also created by the reaction of selenium (IV) oxide with hydrogen sulfide :

${\displaystyle \mathrm {SeO_{2}+2\ H_{2}S\longrightarrow \ SeS_{2}+2\ H_{2}O} }$

use

Selenium sulfides are a common component of anti-dandruff shampoos due to their fungicidal and dandruff-relieving effects. These usually contain 1% of the active ingredient. Selenium sulphides are contained in higher concentrations (2.5%) in pastes and suspensions sold in pharmacies for the treatment of seborrheic eczema . Higher concentrations require a prescription . Since selenium sulphide is not absorbed, there is no risk of poisoning if the preparations are used correctly.

fiction

In the film Evolution , selenium was mentioned as an active ingredient by Head & Shoulders . So a group of academics tried shampoo of this brand to stop an alien invasion after they found out that the alien life form is sensitive to selenium. In fact, the modern shampoo of this brand no longer contains selenium sulfide and instead zinc pyrithione is used as a dandruff -reducing component.

Individual evidence

1. ↑ ^{a b c} Entry on selenium disulphide in the GESTIS substance database of the IFA , accessed on September 4, 2016(JavaScript required) .
2. ↑ Ralf Steudel , Risto Laitinen: Cyclic selenium sulfides . In: Inorganic Ring Systems (= Topics in Current Chemistry. 102). Springer, Berlin / Heidelberg, 1982, ISBN 3-540-11345-2 , pp. 177-197, doi : 10.1007 / 3-540-11345-2_11 .
3. ^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 , p. 626.
4. ^ Evolution (2001) Trivia