Silicon disulfide
# Silicon disulfide

Silicon disulfide is the inorganic compound with the formula $SiS_2.$ Like silicon dioxide, this material is polymeric, but it adopts a 1-dimensional structure quite different from the usual forms of $SiO_2.$

## Synthesis, structure, and properties

The material is formed by heating silicon and sulfur or by the exchange reaction between $SiO_2$ and $Al_2S_3.$ The material consists of chains of edge-shared tetrahedra, $Si(μ-S)_2Si(μS)_2,$ etc.

Like other silicon sulfur-compounds (e.g., bis(trimethylsilyl)sulfide) $SiS_2$ hydrolyzes readily to release $H_2S.$ In liquid ammonia it is reported to form the imide $Si(NH)_2$ and $NH_4SH,$ but a recent report has identified crystalline $(NH_4)_2[SiS_3(NH_3)]·2NH_3$ as a product which contains the tetrahedral thiosilicate anion, $SiS_3(NH_3).$

Reaction with ethanol gives the alkoxide tetraethyl orthosilicate and $H_2S.$ With bulky tert-butanol, alcoholysis gives tris(tert-butoxy)silanethiol:

    3 $(CH_3)_3COH$ + $SiS_2$ → $[(CH_3)_3CO]_3SiSH$ + $H_2S$

Reaction with sodium sulfide, magnesium sulfide and aluminum sulfide give thiosilicates.

$SiS_2$ is claimed to occur in certain interstellar objects.

