Thiirane, more commonly known as ethylene sulfide, is the cyclic

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the formula C₂H₄S. It is the smallest sulfur-containing

heterocycle A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, proper ...

and the simplest

episulfide In organic chemistry, an episulfide is an organic compound that contain a saturated, heterocyclic ring consisting of two carbon atoms and one sulfur atom. It is the sulfur analogue of an epoxide or aziridine. They are also known as thiiranes, ol ...

. Like many organosulfur compounds, this species has a highly unpleasant odour. Thiirane is also used to describe any derivative of the parent ethylene sulfide.

Structure and properties

According to

electron diffraction Electron diffraction is a generic term for phenomena associated with changes in the direction of electron beams due to elastic interactions with atoms. It occurs due to elastic scattering, when there is no change in the energy of the electrons. ...

, the C-C and C-S distances in ethylene sulfide are respectively 1.473 and 1.811 Å. The C-C-S and C-S-C angles are respectively 66.0 and 48.0°. The microwave and infrared spectra were studied experimentally and computationally.

Preparation and reactions

It can be prepared by the reaction of

ethylene carbonate Ethylene carbonate (sometimes abbreviated EC) is the organic compound with the formula (CH2O)2CO. It is classified as the cyclic carbonate ester of ethylene glycol and carbonic acid. At room temperature (25 °C) ethylene carbonate is a tra ...

and KSCN. For this purpose the KSCN is first melted under vacuum to remove water. :KSCN + C₂H₄O₂CO → KOCN + C₂H₄S + CO₂ Ethylenesulfide adds to amines to afford 2-mercaptoethylamines, which are good chelating ligands. :C₂H₄S + R₂NH → R₂NCH₂CH₂SH This process is often called mercaptoethylation. Oxidation of thiirane with

periodate Periodate ( ) is an anion composed of iodine and oxygen. It is one of a number of oxyanions of iodine and is the highest in the series, with iodine existing in oxidation state +7. Unlike other perhalogenates, such as perchlorate, it can exist in ...

gives ethylene episulfoxide.

References

{{sulfur compounds Episulfides