Page "Technetium" Paragraph 4

Many early researchers, both before and after the periodic table was published, were eager to be the first to discover and name the missing element ; its location in the table suggested that it should be easier to find than other undiscovered elements.

It was first thought to have been found in platinum ores in 1828 and was given the name polinium, but turned out to be impure iridium.

Then, in 1846, the element ilmenium was claimed to have been discovered, but later was determined to be impure niobium.

This mistake was repeated in 1847 with the " discovery " of pelopium.