Indium chalcogenides


The indium chalcogenides include all compounds of indium with the chalcogen elements, oxygen, sulfur, selenium and tellurium.. The best-characterised compounds are the In and In chalcogenides e.g. the sulfides In2S3 and InS.

This group of compounds has attracted a lot of research attention because they include semiconductors, photovoltaics and phase-change materials. In many applications indium chalcogenides are used as the basis of ternary and quaternary compounds such as indium tin oxide, ITO and copper indium gallium selenide, CIGS.
Some compounds that were reported and have found their way into text books have not been substantiated by later researchers. The list of compounds below shows compounds that have been reported, and those compounds that have not had their structure determined, or whose existence has not been confirmed by the latest structural investigations, are in italics.
oxidesulfideselenidetelluride
In2OIn2Se
In4S3In4Se3In4Te3
In5S4
InSInSeInTe
In6S7In6Se7
In3S4In3Te4
In7Te10
In2O3In2S3In2Se3In2Te3
In3Te5
In2Te5

There are a lot of compounds, the reason for this being that indium can be present as
The compound In2Te5 is a polytelluride containing the Te32− unit.

None of the indium chalcogenides can be described simply as ionic in nature, they all involve a degree of covalent bonding. However, in spite of this it is useful to formulate the compounds in ionic terms to get an insight into how the structures are built up. Compounds almost invariably have multiple polymorphs, that is they can crystallise in slightly different forms depending on either the method of production, or the substrate upon which they are deposited. Many of the compounds are made up of layers, and it is the different ways that the layers are stacked that is a cause of polymorphism.

In2O, In2Se

In4S3, In4Se3, In4Te3

In5S4

InS, InSe, InTe

;InS, InSe
;InTe

In6S7, In6Se7

In6S7 is an n-type semiconductor.

In3Te4

In7Te10

In2S3, In2Se3, In2Te3

;In2S3
;In2Se3
;In2Te3

In3Te5

In2Te5