Hydrogen disulfide is the

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

with the formula . This hydrogen chalcogenide is a pale yellow volatile liquid with a camphor-like odor. It decomposes readily to

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist ...

() and elemental

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

Structure

The connection of atoms in the hydrogen disulfide molecule is . The structure of hydrogen disulfide is similar to that of

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...

, with C₂ point group symmetry. Both molecules are distinctly nonplanar. The dihedral angle between the and planes is 90.6°, compared with 111.5° in . The bond angle is 92°, close to 90° for unhybridized divalent sulfur.

Synthesis

Hydrogen disulfide can be synthesised by cracking polysulfanes () according to this idealized equation: : The main impurity is trisulfane (). The precursor polysulfane is produced by the reaction of hydrochloric acid with aqueous sodium polysulfide. The polysulfane precipitates as an oil.

Reactions

Upon contact with water or alcohols, hydrogen disulfide readily decomposes under ambient conditions to

and sulfur. It is more acidic than

, but the p''K''_a has not been reported. In organosulfur chemistry, hydrogen disulfide adds to alkenes to give

disulfide In chemistry, a disulfide (or disulphide in British English) is a compound containing a functional group or the anion. The linkage is also called an SS-bond or sometimes a disulfide bridge and usually derived from two thiol groups. In inorg ...

s and thiols.

Quantum tunneling and its suppression in deuterium disulfide

The deuterated form of hydrogen disulfide, deuterium disulfide (dideuterodisulfane), has a similar geometry to , but its tunneling time is slower, making it a convenient test case for the quantum Zeno effect, in which frequent observation of a quantum system suppresses its normal evolution. Trost and Hornberger have calculated that while an isolated molecule would spontaneously oscillate between left and right chiral forms with a period of 5.6 milliseconds, the presence of a small amount of inert helium gas should stabilize the chiral states, the collisions of the helium atoms in effect "observing" the molecule's momentary chirality and so suppressing spontaneous evolution to the other chiral state.

Health effects

In high concentrations, it can cause dizziness, disorientation and ultimately unconsciousness.

Historic literature

* *Georg Brauer: ''Handbook of Preparative Inorganic Chemistry'' Volume I, page 391, Wiley, 1963. *von Richter, Victor: Translated by Edgar F Smith, "A Text-Book of Inorganic Chemistry", Page 111, P. Blakiston, Son & Co., 1893

References

{{Hydrides by group Hydrogen compounds Disulfides