Atomic number 49, indium was discovered by Ferdinand Reich in 1863 in Germany. His intention was to examine whether zinc sulphide ore (sphalerite) contained thallium. But his research led to the discovery of a new element after his detailed observations. He roasted the ore to remove most of the sulphur and decomposed the remaining with hydrochloric acid. A straw- coloured solid appeared which he suspected to be the sulphide of a new element. He further studied it by getting an emission spectrum for the sample. But unfortunately, he was colour blind and was not able to accurately analyze this. He asked for help from a fellow German chemist named Hieronymus T Richter, who found an indigo line. This line was a new one and did not match any known element.
This information helped them to understand that a new element was present in the sample. Thus they discovered indium.
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