Editing Indium (section)

===Other oxidation states===
Less frequently, indium forms compounds in oxidation state +2 and even fractional oxidation states. Usually such materials feature In–In bonding, most notably in the [[indium halides|halides]] In<sub>2</sub>X<sub>4</sub> and [In<sub>2</sub>X<sub>6</sub>]<sup>2−</sup>,<ref name="can82">{{cite journal| doi =10.1139/v82-102| title =Neutral complexes of the indium dihalides| date =1982| last1 =Sinclair| first1 =Ian| last2 =Worrall| first2 =Ian J.| journal =Canadian Journal of Chemistry| volume =60| issue =6| pages =695–698| doi-access =free}}</ref> and various subchalcogenides such as In<sub>4</sub>Se<sub>3</sub>.<ref name="Greenwood287">Greenwood and Earnshaw, p. 287</ref> Several other compounds are known to combine indium(I) and indium(III), such as In<sup>I</sup><sub>6</sub>(In<sup>III</sup>Cl<sub>6</sub>)Cl<sub>3</sub>,<ref>{{cite journal |doi = 10.1002/anie.199108241 |title = In7Cl9—A New"Old" Compound in the System In-Cl |date = 1991 |last1 = Beck |first1 = Horst Philipp |last2 = Wilhelm |first2 = Doris |journal = Angewandte Chemie International Edition in English |volume = 30 |issue = 7 |pages = 824–825}}</ref> In<sup>I</sup><sub>5</sub>(In<sup>III</sup>Br<sub>4</sub>)<sub>2</sub>(In<sup>III</sup>Br<sub>6</sub>),<ref>{{cite journal| doi =10.1002/anie.199511261| title =Synthesis, Structure, and Decay of In4Br7| date =1995| last1 =Dronskowski| first1 =Richard| journal =Angewandte Chemie International Edition in English| volume =34| issue =10| pages =1126–1128}}</ref> and In<sup>I</sup>In<sup>III</sup>Br<sub>4</sub>.<ref name="can82" />