Ilmenium was the proposed name for a new element found by the chemist R. Hermann in 1847. During the analysis of the mineral

samarskite Samarskite is a radioactive rare earth mineral series which includes samarskite-(Y), with the chemical formula and samarskite-(Yb), with the chemical formula . The formula for samarskite-(Y) is also given as . Samarskite crystallizes in the ort ...

, he concluded that it does contain an element similar to

niobium Niobium is a chemical element; it has chemical symbol, symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and Ductility, ductile transition metal. Pure niobium has a Mohs scale of mineral hardness, Mohs h ...

and

tantalum Tantalum is a chemical element; it has Symbol (chemistry), symbol Ta and atomic number 73. It is named after Tantalus, a figure in Greek mythology. Tantalum is a very hard, ductility, ductile, lustre (mineralogy), lustrous, blue-gray transition ...

. The similar reactivity of niobium and tantalum complicated preparation of pure samples of the metals and therefore several new elements were proposed, which were later found to be mixtures of niobium and tantalum. The differences between tantalum and niobium, and the fact that no other similar element was present, were unequivocally demonstrated in 1864 by

Christian Wilhelm Blomstrand Christian Wilhelm Blomstrand (20 October 1826 – 5 November 1897) was a Swedish mineralogist and chemist. He was a professor at the University of Lund from 1862-1895, where he isolated the element niobium in 1864. He developed an early version o ...

, and

Henri Etienne Sainte-Claire Deville Henri is the French form of the masculine given name Henry, also in Estonian, Finnish, German and Luxembourgish. Bearers of the given name include: People French nobles * Henri I de Montmorency (1534–1614), Marshal and Constable of France * ...

, as well as Louis J. Troost, who determined the formulas of some of the compounds in 1865 and finally by the Swiss chemist

Jean Charles Galissard de Marignac Jean Charles Galissard de Marignac (24 April 1817 – 15 April 1894) was a Swiss chemist whose work with atomic weights suggested the possibility of isotopes and the packing fraction of nuclei. His study of the rare earth elements led to ...

Although it had been proven that ilmenium is only a mixture of niobium and tantalum, Hermann continued publishing articles on ilmenium for several years. The name "ilmenium" is a reference to the

Ilmensky Mountains The Ilmensky Mountains () are located in the Southern Urals in the Chelyabinsk Oblast on the administrative territory of Miass in Chebarkulsky and Argayashsky districts. They are on the Tentative list of UNESCO World Heritage Sites. They a ...

References

Misidentified chemical elements Niobium Tantalum {{chem-hist-stub