Ilmenium

Ilmenium refers to a purported chemical element, with the symbol Il, believed to exist in the early 19th century. It was claimed to have been discovered by Hermann in 1842 in ilmenite from the Ilmen Mountains in Russia.

The claim of its existence was quickly discredited. Subsequent analyses showed that the substance Hermann identified as ilmenium was actually niobium, already discovered in 1801 by Charles Hatchett, albeit under the name columbium. The name columbium was used primarily in the United States, while niobium was more widely accepted in Europe. Ultimately, niobium received international recognition.

The existence of ilmenium highlights the challenges in early element discovery, particularly with rare earth elements, where chemical separation and identification were difficult with the analytical techniques available at the time. The name "Ilmenium" is now considered obsolete in the context of established chemical nomenclature.