Periodic Table of Rejected Elements

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Extremium, catium, cyclonium and pandemonium: elements that you won’t find in the periodic table in classrooms and laboratories. However, they’re all names that have been suggested but rejected for elements in years gone by. This table takes a look at some of the different names that have been suggested or used in the past for various elements; below, we examine their origins, and the reasons for their rejection.

The research for this post was primarily done using “The Lost Elements: The Periodic Table’s Shadow Side”, which details the history of erroneous element discoveries and naming controversies. It’s well worth checking out for a lot more detail on the history of some of the names featured here, as well as that of many more.

Element 4: Glucinium (Beryllium)

The French chemist, Louis Nicolas Vauquelin, examined both emerald and beryl and correctly reported that they contained a new element in 1798. He named this element glucine, with the symbol Gl, but as this name was very similar to that of the amino acid glycine it was criticised. When the first samples of the element were later isolated in 1828, the acceptance of the name beryllium, suggested by another chemist, Martin Henrich Klaproth, became more widespread. However, it wasn’t until 1949 that IUPAC ruled the element should be exclusively called beryllium.

Element 5: Boracium (Boron)

Boron was isolated at the same time by the French chemists Louis-Joseph Gay-Lussac and Louis-Jacques Thénard, as well as the English chemist Sir Humphrey Davy, in 1808. Davy proposed the name of boracium for the element, which was eventually modified to boron.

Element 7: Azote (Nitrogen)

Antoine Lavoisier discovered element 7 in 1776, and later proposed the name azote. Other chemists weren’t enamoured with this name, however, and it eventually became nitrogen.

Element 9: Fluore (Fluorine)

Though chemists didn’t isolate fluorine until 1886, in 1816 André-Marie Ampère proposed that hydrofluoric acid, like hydrochloric acid, was a binary compound consisting of hydrogen and another element. He proposed the name of fluor or phtore for this element, but left the choice to the English chemist Sir Humphrey Davy, with whom he had corresponded on the subject. This eventually became the element’s current name, fluorine.

Element 10: Novum (Neon)

Neon was discovered by the Scottish scientist Sir William Ramsay, who also discovered all of the other elements in group 18 of the periodic table (bar the recently discovered element 118). He discovered neon in 1898, and decided to use as the element’s name the suggestion of his 13 year old son, ‘novum’. However, Ramsay wanted the name to be derived from Greek, like the other noble gases he had discovered, so he made the slight modification to the element’s current name, neon.

Element 12: Magnium (Magnesium)

Sir Humphrey Davy isolated magnesium in 1808, and called it magnium. He named it this, rather than magnesium after the oxide from which it had been obtained (magnesia alba), because he didn’t want the name to be confused with that of another element, manganese. However, the name magnesium persisted, though magnium is still used in some countries. Talcinium was another suggested name, which came later in 1828, though this wasn’t a suggestion that was given serious credence.

Element 21: Gadenium (Scandium)

In 1886, a Scotsman, Alexander Pringle, claimed to have discovered four new elements, named polymnestum, erebodium, gadenium and hesperisium. Unfortunately for Pringle, his determination of the atomic weights of these elements was pretty poor, and additionally he’d failed to describe any new elements. It’s most likely that gadenium was actually the already discovered scandium, perhaps also contaminated with iron. The other ‘new’ elements were similarly simply incorrect deductions by Pringle, and were most likely mixtures of elements already in existence.

Element 22: Menachite (Titanium)

Englishman William Gregor discovered titanium in 1789, and gave it the name menachite after the black sand in which he found it. Five years later, Martin Henrich Klaproth discovered the same element, naming it titanium, and didn’t realise it was identical to Gregor’s element until three years later. Despite Gregor’s priority, titanium stuck as the name of the element, and menachite was forgotten.

Element 23: Panchromium (Vanadium)

Element 23 was discovered in 1801 by Spanish-Mexican Andrés Manuel de Río, who named it panchromium due to the wide variety of colours its salts exhibited. He later changed the name to erythronium, but when his correct claim for this being a new element was erroneously challenged, he retracted his discovery. Element 23 was rediscovered in 1831 by the Swedish chemist Nils Gabriel Sefström, who chose the name vanadium for the element, whilst confirming the original discovery of Río to be correct.

In 1879, Arcangelo Scacchi, an Italian mineralogist, claimed the discovery of a new element in the crusts left over by the eruption of Mount Vesuvius over two centuries earlier. He named this element vesbium after the volcano. Later analysis showed that this element was merely vanadium.

Element 32: Neptunium (Germanium)

If you’re familiar with the periodic table, you’ll know that neptunium is the name of an element – but it’s element 93, not element 32. The german chemist Clemens A. Winkler isolated element 32 in 1886, and originally wanted to call it neptunium. However, he soon realised that this name had been used for the erroneous claimed discovery of a new element by John Herschel 30 years or so earlier. So that the two wouldn’t be confused, he named his element germanium instead.

Element 33: Polymnestum (Arsenic)

A name given by Alexander Pringle to another of his erroneously claimed new elements (see element 21). Polymnestum’s proposed atomic weight and description corresponds most closely to that of arsenic, which was already known.

Element 34: Hesperisium (Selenium)

Another of Alexander Pringle’s failed elements. His description of hesperisium corresponds closely to that of selenium, already known at the time.

Element 35: Muride (Bromine)

Element 35 was discovered by a Frenchman, Antoine-Jérôme Balard, and he suggested the name muride. However, the French Academy of Sciences proposed brome, which eventually became bromine.

Element 36: Eosium (Krypton)

Element 36, another noble gas, was of course discovered by Sir William Ramsey, who discovered the whole family. A friend with whom he worked on the discovery, Marcellin Berthelot, suggested the name of eosium, derived from the Greek for ‘dawn’. However, this clearly wasn’t a suggestion that Ramsay took on board, as he gave the element the name krypton.

Element 39: Lucium (Yttrium)

In 1896 a French chemist, Prosper Barrière, claimed the discovery of a new element which he named lucium. However, later spectral analysis of the samples showed them to be nothing more than impure yttrium. Oddly, this represented the only article Barrière ever published, and it was supposedly endorsed by several renowned chemists at the time, who later denied their involvement.

Element 41: Columbium (Niobium)

The English chemist, Charles Hatchett, claimed the discovery of a new element that he called columbium in 1801. After the discovery of tantalum a year later, it was thought that columbium and tantalum were one and the same. However, subsequently, another chemist, Heinrich Rose, suggested that the mineral in which columbium was found actually contained tantalum and two other elements. These he named niobium and pelopium. Later, columbium and niobium were actually shown to be the same element – not columbium and tantalum.

This confusion is reflected in periodic tables from the time. Both columbium and niobium were used to refer to element 41 up until 1949, when IUPAC ruled that niobium should be the official name of the element.

Element 42: Erebodium (Molybdenum)

Another of Alexander Pringle’s failed elements (see element 21), which most closely corresponded to the already known molybdenum.

Element 43: Masurium (Technetium)

Element 43 doesn’t occur naturally outside of uranium deposits, where it is created in very small amounts as a fleeting byproduct of spontaneous fission, before it too decays. German chemists Walter & Ida Noddack claimed the discovery of element 43 in 1925, at the same time they discovered rhenium, and named it masurium after a region of modern-day Poland. However, other chemists cast doubt on their discovery of the element, and it was never corroborated by independent experiments. It was later created artificially by Carlo Perrier and Emilio Segrè in 1936, and named technetium.

Element 43’s naming history doesn’t stop there though – it also has links with rhenium, as we’ll discover when we evaluate the history of element 75’s name.

Element 44: Polinium (Ruthenium)

Ruthenium was discovered in 1844 by Karl Ernst Klaus, born in present-day Tartu, Estonia (then part of Russia). Polinium was the name proposed by Gottfried Wilhelm Osann, who claimed he had discovered it back in 1828. However, his element is thought to have been merely impure iridium – and Osann had previously as much as admitted this himself, scuppering his claim.

Element 46: Ceresium (Palladium)

Palladium was discovered by William John Hyde Wollaston in 1803. He originally proposed calling the element ceresium, but as the very similar name cerium was proposed for the first of the lanthanide elements before he published his results, he changed the name to palladium instead.

Element 48: Melinum (Cadmium)

Cadmium was discovered by two chemists, Friedrich Stromeyer and Karl Hermann, simultaneously. Later, another chemist, Karl Karsten, thought he had discovered a new element in zinc deposits that he named melinum; later, this was shown to be merely cadmium.

Element 52: Pilsum (Tellurium)

Element 52 was originally discovered in 1782 by a Hungarian scientist, Ferenc Müller von Reichenstein, who gave it the catchy name of ‘metallicum problematicum’. It was later rediscovered in 1789 by another Hungarian, Pál Kitaibel, who named it pilsum. The German Martin Heinrich Klaproth also isolated it in 1798, and it was he who gave it its present name of tellurium.

Element 56: Plutonium (Barium)

In 1812, Edward Daniel Clarke claimed the discovery of element 56, and proposed the name plutonium. However, this was rejected by other chemists who had also isolated the element, who preferred barium. Plutonium, of course, eventually made it to the periodic table as element 94 instead.

Element 58: Ochroite (Cerium)

Martin Heinrich Klaproth (yes, him again) discovered element 58 in 1803, at the same time as Jöns Jakob Berzelius. Klaproth proposed the name ochroite, but Berzelius won out with his suggestion of cerium.

Element 60: Didymium (Neodymium)

Neodymium and praseodymium (element 61) were once mistaken to be just one element, didymium. Discovered in 1842, it was over 40 years before its dual nature was eventually realised.

Element 61: Florentium (Promethium)

Florentium was the name given to element 61 in 1924 when its discovery was claimed by Italian scientists Luigi Rolla and Lorenzo Fernandes. The name was after the Italian city of Florence. However, their findings were later shown to be erroneous.

Element 62: Decipium (Samarium)

The name decipium was given to element 62 by Swiss chemist Marc Delafontaine in 1878, who later realised he’d actually had a mixture of several elements including element 62. Before he realised this, French chemist Paul Émile Lecoq de Boisbaudran had isolated the element’s oxide in 1879, and he named it samarium. After the mineral in which it was found. This in turn was named after an obscure Russian mining engineer, Vasili Samarsky-Bykhovets, making him technically the first person to have an element named after them.

Element 67: Philippium (Holmium)

Element 67 was also discovered by Marc Delafontaine in 1878, and he named it philippium. It was later rediscovered, and named holmium; this name had already passed into common usage by the time Delafontaine’s priority was established.

Element 70: Aldebaranium (Ytterbium)

Elements 70 and 71 were discovered at similar times by two different chemists: Frenchman Georges Urbain and Austrian Carl Auer von Welsbach. Welsbach wanted to name element 70 Aldebaranium, though Urban was credited wit the discovery of both, and chose neb-ytterbium (later changed to simply ytterbium).

Element 71: Cassiopeium (Lutetium)

See above; Welsbach’s chosen name for lutetium was cassiopeium. Urbain’s was lutecium, later changed to present-day lutetium.

Element 72: Celtium (Hafnium)

Element 72’s discovery was initially claimed in 1911 by Georges Urbain, who named it celtium. However, he later realised that his claim was erroneous. Despite this, there was still debate over this name, and the name later given to the element, hafnium. IUPAC ruled in favour of hafnium in 1930.

Element 74: Scheelium (Tungsten)

Scheelium was the name proposed by Martin Heinrich Klaproth to honour Carl Wilhem Scheele, who had first identified the element in mineral deposits. However, this name was rejected.

Element 75: Nipponium (Rhenium)

Rhenium was discovered and named by German chemists Walter & Ida Noddack, but may actually have been discovered in 1908 by Japanese chemist Masataka Ogawa. However, he thought he had discovered element 43. He proposed the name nipponium, after Japan, but his findings were not confirmed to be element 43, and as such his claim was unsuccessful. Later analysis suggests that he had actually discovered element 75, rhenium, immediately below element 43 (technetium) in the table.

This still goes down as an erroneous discovery, simply because Ogawa never realised he’d isolated a different element. It’s an interesting one though, because Japanese scientists might want to name element 113 nipponium, having been credited with its discovery. IUPAC rules state that elements can’t take a name previously suggested for another element, however. That said, we’ll find that IUPAC don’t exactly stick rigidly to that rule…

Element 85: Anglo-Helvetium (Astatine)

Astatine was the victim of a number of false discoveries, and hence has a range of fleetingly used names. These include dor, viennium, alabamine, and leptine. Anglo-helvetium was another claimed discovery, from a collaboration between the Swiss Walter Minder and the English Alice Leigh-Smith. They named their proposed element anglo-helvetium after their collaboration, but when their experiments were repeated no evidence of the element was found.

Element 86: Niton (Radon)

Niton was one of the names proposed by Sir William Ramsay for element 86. This name was accepted by the International Committee of Atomic Weights in 1912, but later its name was later changed to that suggested by the German Friedrich Ernst Dorn, Radon. Radon was also commonly known as emanation, even as late as the 1960s.

Element 87: Catium (Francium)

Francium has had a range of proposed names over the years: alkalinium, russium, virginium, and moldavium have all been proposed as a consequence of claimed discoveries. Catium was the name proposed by its eventual genuine discoverer, Margeurite Perey, a French physicist. However, it was rejected by one of her supervisors, Irène Joliot-Curie (Marie Curie’s daughter), who thought it would just bring the image of cats to the minds of English chemists, instead of the word ‘cation’ which was intended. Perry subsequently suggested Francium instead.

Element 88: Masrium (Radium)

In 1892, chemists Henry Droop Richmond and Hussein Off claimed to have found a new element in a mineral found in remote Egypt. They named the element masrium after Egypt. The atomic weight of the element they reported would have been that of radium, unknown at the time, but there is no doubt that their analyses were flawed, and they had not, in fact, discovered a new element.

Element 89: Emanium (Actinium)

Element 89 was discovered twice: first by André-Louis Debierne in 1899, who named it actinium, and independently by Friedrich Oskar Giesel in 1902, who named it emanium. As Debierne had priority, his name stuck.

Element 91: Brevium (Protactinium)

An isotope of protactinium was first discovered by Kasimir Fajans and Oswald Helmuth Göhring in 1913; they named it brevium due to the fact that it had a very short half life. Later in 1917, Lise Meitner and Otto Hahn discovered a more stable isotope, naming it protactinium, and it is this name that the element carries today.

Element 92: Klaprothium (Uranium)

Martin Friedrich Klaproth isolated the element uranium in 1789. He originally named it uranit, after the recently discovered planet uranus, and later changed this to uranium. Later, it was proposed by some that the element should be named klaprothium after its discover, but this suggestion was rejected.

Element 93: Ausonium (Neptunium)

Enrico Fermi, the famous Italian physicist, claimed the discovery of element 93 and element 94 in 1934. He proposed the name Ausonium for element 93, and the name Hesperium for element 94 – both were based on ancient names for Italy. Several days after winning the Nobel Prize in chemistry, for both his research on uranium and his discovery of the two new elements, it was shown that the uranium decay series he claimed produced the elements only produced uranium isotopes. Element 93 was later produced in 1940, and named neptunium.

Element 94: Extremium (Plutonium)

Extremium was reportedly one of the names considered by US chemists on their discovery of element 94 in 1940. However, the eventually settled on Plutonium (with Seaborg’s little joke of its symbol being Pu instead of Pl) in order to continue the series of planet-based element names.

Element 95: Pandemonium (Americium)

The discovery of elements 95 and 96 in 1945 spurred a host of suggestions for their names. Glenn Seaborg reportedly related that his colleague, Tom Morgan, referred to elements 95 and 96 as pandemonium and delirium. Supposedly, he considered proposing these names to IUPAC’s naming committee. Though a large number of names were suggested, Seaborg eventually plumped for americium for element 95.

Element 96: Bastardium (Curium)

Bastardium was one of the suggestions to Glenn Seaborg for element 96’s name, supposedly alluding to the mythical tale of pluto’s rape of persephone, and presumably therefore providing a tenuous link to plutonium. Unsurprisingly, it wasn’t selected to be the element’s official name!

Element 97: Mendelevium (Berkelium)

Although element 97 was discovered in 1949, Soviet Union scientists also claimed its discovery shortly after, and proposed the name mendelevium. Although their claim was rejected, they eventually got their wish for an element named after the father of the modern periodic table, as element 101 was named mendelevium.

Element 98: Cyclonium (Californium)

One of the many proposed names for element 98, after the cyclotrons used to create the superheavy elements.

Element 99: Losalium (Einsteinium)

Element 99 was discovered by a number of laboratories simultaneously in the early 1950s. Losalium was the name suggested by a team in Los Alamos, but it eventually ended up being named Einsteinium by Glenn Seaborg.

Element 100: Phoenicium (Fermium)

One of the proposed names for element 100 was phoenicium, suggested by scientists at Argonne National Laboratory near Chicago. However, this was rejected in favour of its eventual name, Fermium. Other suggested names included centurium, uclasium, and arconium.

Element 102: Joliotium (Nobelium)

The elements after fermium were involved in the ‘transfermium wars’ – arguments between different teams of scientists who claimed to have discovered the elements first, and therefore had the right to propose their names. Element 102’s discovery was claimed in the early 1960s by various teams from Sweden, the USA, and Russia, but it is now widely accepted that the Russian team’s work had priority, and they are officially recognised as the discoverers of the element.

The Russian team proposed the name of Joliotium for the element, but the Swedish team had also claimed priority, and named the element Nobelium. However, their results could not be replicated, and they later retracted their claim. Despite this, their name suggestion had been immediately approved by IUPAC, and the name was again ratified in 1994, on the basis that it had passed into common usage.

Element 104: Kurchatovium (Rutherfordium)

Element 104’s discovery was claimed by both Russian and US scientists. The Russians wanted to name it kurchatovium, after their former head of nuclear research. The Americans, however, won out with their claim for priority, and named the element Rutherfordium.

Element 105: Nielsbohrium (Dubnium)

Another disputed discovery between Russian and US scientists. The Russian scientists proposed nielsbohrium, after the Danish scientist Niels Bohr, whereas the US scientists proposed hahnium after German chemist Otto Hahn. The dispute wasn’t resolved until 1997, when dubnium was agreed on as a compromise name, after Dubna in Russia.

Element 106: Alvarezium (Seaborgium)

Alberto Ghiorso, in charge of research into new elements at Berkeley, wanted to name element 106 alvarezium, after physicist Luis Walter Alvarez. However, his team weren’t enamoured with the suggestion, and eventually they suggested seaborgium, after Glenn Seaborg. This caused some controversy, as Seaborg was still alive at the time, and IUPAC rules state that elements can’t be named after living people. As such, the name was rejected, and rutherfordium was the name given to the element by IUPAC instead. This didn’t go down well with the American Chemical Society, who essentially complained until IUPAC reconsidered the decision. The name rutherfordium was instead given to element 104.

Element 109: Hahnium (Meitnerium)

Another of the disputed elements, hahnium was the name suggested for element 109 by Russian scientists, after German chemist Otto Hahn. That it ended up being named meitnerium instead, after Lise Meitner, is seen by many to be a fair reflection of the snubbing of Meitner for a Nobel Prize. Hahn received a Nobel Prize for his on nuclear fission, despite the fact that she was also instrumental in the work. It’s perhaps fitting then, that Meitner gets an element named after her, whereas Hahn’s name can’t be suggested as an element name again due to IUPAC rules that state a rejected name can’t be reused.

Element 114: Russium (Flerovium)

Russium was a suggested name for element 114 but was rejected due to it having previously been suggested for a false discovery of element 43. However, the eventual name given to the element, flerovium, had also been previously suggested and rejected for element 102. Under IUPAC rules, this should mean that the name doesn’t get another shot at being used for another element; it’s unclear why IUPAC overlooked their own rule in this particular case.

Element 116: Leosium (Livermorium)

Leosium had already been suggested as the name of element 43 after an unconfirmed discovery, so IUPAC rules stated that it could not be used again. Element 116 was eventually named livermorium, after the laboratory in which it was discovered.

Elements 113, 115, 117 and 118

These elements are the most recently discovered in the periodic table. Though a multitude of names have been suggested for these elements, they aren’t included here as no final name has yet been decided for them. You can see a selection of the suggestions here.

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References & Further Reading