List of misidentified chemical elements

Chemical elements that have been mistakenly "discovered". Further investigation showed that their discovery was either mistaken, that they have been mistaken from an already-known element, or mixture of two elements, or that they indicated a failing in theory where a new element had been assumed rather than some previously unknown behaviour.^{[lower-roman 1]}

Name	Symbol	Atomic number	Actual element	Discovery date	Discoverer
Alabamium	Ab	85	Astatine	1931	Fred Allison
Alkalinium		87	Francium	1926	Gerald J. F. Druce, Frederick H. Loring
Anglohelvetium						See Helvetium
Arconium				1911	J. W. Nicholson
Asterium				1898	Norman Lockyer, Carl David Tolmé Runge, Friedrich Paschen
Aurorium				1874	William Huggins	[1]
Ausenium	Ao	93	Neptunium	1934	Enrico Fermi	[2][3]
Austrium		31	Gallium	1886	Eduard Linnemann	Hypothesised from spectral line observations in the rare-earth mineral orthite.[4] It was later confirmed that these lines were due to the recently discovered gallium.
Berzelium	Bz	90	Thorium	1901	Charles Baskerville	See Carolinium
Bohemium		93	Neptunium	1934	Odolen Koblic
Carolinium	Cn	90	Thorium	1901	Charles Baskerville	With Berzelium, erroneously identified as a mixture of three elements, with thorium, during work at the University of North Carolina.[5]
Coronium		26	Iron	1869	Charles Augustus Young and William Harkness	Hypothesised from a 530.3 nm green emission line in the solar coronal spectrum. Later, around 1902, renamed as Newtonium. In the 1930s recognised as highly ionized iron, rather than a new element.
Cyclonium		61	Promethium	1941	H. B. Law, Ohio State University
Dakin	Dk	85	Astatine	1937	Rajendralal De Cepare
Davyum			Iridium and rhodium	1877	Serge Kern	[6]
Decipium			Samarium and other rare earths	1878	Marc Delafontaine	Thought to have been isolated from the mineral samarskite in 1878.[7]
Dianium			Niobium and tantalum	1860	Wolfgang Franz von Kobell	See Pelopium
Didymium			Praseodymium and neodymium	1841	Carl Mosander
Dorine		85	Astatine	1936	Horia Hulubei, Yvette Cauchois
Eka-caesium		87	Francium
Eka-rhenium		107	Bohrium
Florentium		61	Promethium	1924	Luigi Rolla and Lorenzo Fernandes
Ghiorsium	Gh	118	Oganesson	1999	Lawrence Berkeley National Laboratory
Gnomium			Similarities to nickel and iron	1892	Gerhard Krüss and F. W. Schmidt	Not discovered, but hypothesised to explain discrepancies within the iron group elements for an early periodic table ordered by mass. The concept of atomic number clarified the situation without requiring the invention of a new element.
Helvetium		85	Astatine	1940	Walter Minder	Rediscovered [sic] in 1942 and named Anglohelvetium
Hesperium	Hs	94	Plutonium	1934	Enrico Fermi	[2][3]
Illinium		61	Promethium	1926	Smith Hopkins and Len Yntema, University of Illinois at Urbana–Champaign
Ilmenium			Niobium and tantalum	1847	R. Hermann	See Pelopium
Lucium		39	Yttrium	1896	Prosper Barrière
Masurium		43	Technetium	1925	Walter Noddack, Otto Berg, Ida Noddack
Moldavium	Mi	87	Francium	1936	Horia Hulubei, Yvette Cauchois
Monium				1898		See Victorium
Muriaticum		17	Chlorine	1774	Carl Wilhelm Scheele
Murium				1785	Claude Louis Berthollet
Nebulium			Oxygen	1864	William Huggins
Neutronium		0	(Neutronium)	1926	Andreas von Antropoff
Newtonium				1902		See Coronium
Ninovium	Nv	118	Oganesson	1999	Victor Ninov	Studies proved inconsistencies in the data shown from Victor Ninov
Nipponium	Np	75	Rhenium	1908	Masataka Ogawa	[8]
Pelopium			Niobium and tantalum	1846	Heinrich Rose	Confused with mixtures of the difficult to distinguish niobium and tantalum, extracted from the mineral tantalite.[9]
Polinium		77	Iridium	1828	Gottfried Osann
Ptene		76	Osmium	1803	Hippolyte-Victor Collet-Descotils, Antoine François, comte de Fourcroy, Louis Nicolas Vauquelin, Smithson Tennant
Protyle				1816	William Prout
Russium		87	Francium	1925	D. K. Dobroserdov
Sergenium	Sg	108	Hassium	1963	Victor Cherdyntsev
Sequanium		93	Neptunium	1939	Horia Hulubei	Thought to have been present in tantalite ore, actually not present, rather than mis-identified.[10]
Unbibium	Ubb	122	(Unbibium)	2008	Amnon Marinov
Victorium			Gadolinium and terbium	1898	William Crookes
Virginium	Vi (Vm)	87	Francium	1930	Fred Allison
Wasium			Mixture of rare earths	1862	J. F. Bahr	Another element identified in ores from Ytterby.[11]

References

1. I.e. the spectrum of highly-ionised iron being identified as Coronium.

1. Ryden, Barbara; Pogge, Richard. "Interstellar and Intergalactic Medium".
2. Element name etymologies
3. Fermi, Enrico (December 12, 1938). "Artificial radioactivity produced by neutron bombardment" (PDF). Nobel Lecture. pp. 416–417.
4. Linnemann, Eduard (1886). "Austrium, ein neues metallisches Element". Monatshefte für Chemie. 7 (1): 121. doi:10.1007/BF01516564. S2CID 97322406.
5. Baskerville, Charles (1901). "On the Existence of a new Element associated with Thorium". J. Am. Chem. Soc. 23 (10): 761–764. doi:10.1021/ja02036a004.
6. Kern, Serge (1877). "On a new metal, davyum". Philos. Mag. Series 5. 4 (23): 158–159. doi:10.1080/14786447708639315.
7. Delafontaine, Marc (1878). "Sur le décepium, métal nouveau de la samarskite". Journal de pharmacie et de chimie. 28: 540.
8. Yoshihara, H. K. (2004). "Discovery of a new element 'nipponiumʼ: re-evaluation of pioneering works of Masataka Ogawa and his son Eijiro Ogawa". Spectrochimica Acta Part B: Atomic Spectroscopy. 59 (8): 1305–1310. Bibcode:2004AcSpe..59.1305Y. doi:10.1016/j.sab.2003.12.027.
9. Rose, Heinrich (1846). "On a new metal, pelopium, contained in the Bavarian tantalite". Philos. Mag. Series 3. 29 (195): 409–416. doi:10.1080/14786444608645529.
10. Fontani, Marco (2005-09-10). "The Twilight of the Naturally-Occurring Elements: Moldavium (Ml), Sequanium (Sq) and Dor (Do)". International Conference on the History of Chemistry. Lisbon. pp. 1–8. Archived from the original on 2006-02-24.
11. Delafontaine, M. (1864). "Ueber das Wasium". Annalen der Chemie und Pharmacie. 131 (3): 368–372. doi:10.1002/jlac.18641310316.