<Tr> <Td_colspan="2"> <Ul> <Li> view </Li> <Li> talk </Li> <Li> edit </Li> </Ul> references in Wikidata </Td> </Tr> <Ul> <Li> view </Li> <Li> talk </Li> <Li> edit </Li> </Ul> <P> Indium is a chemical element with symbol In and atomic number 49 . It is a post-transition metal that makes up 0.21 parts per million of the Earth's crust . Very soft and malleable, indium has a melting point higher than sodium and gallium, but lower than lithium and tin . Chemically, indium is similar to gallium and thallium, and it is largely intermediate between the two in terms of its properties . Indium was discovered in 1863 by Ferdinand Reich and Hieronymous Theodor Richter by spectroscopic methods . They named it for the indigo blue line in its spectrum . Indium was isolated the next year . </P> <P> Indium is a minor component in zinc sulfide ores and is produced as a byproduct of zinc refinement . It is most notably used in the semiconductor industry, in low - melting - point metal alloys such as solders, in soft - metal high - vacuum seals, and in the production of transparent conductive coatings of indium tin oxide (ITO) on glass . Indium has no biological role, though its compounds are somewhat toxic when injected into the bloodstream . Most occupational exposure is through ingestion, from which indium compounds are not absorbed well, and inhalation, from which they are moderately absorbed . </P>

What group is indium in on the periodic table