Резюме. A summary review for the origin of the names and symbols of all chemical elements discovered up to now are presented along with the reasons for proposing these appellations.

Ключови думи: chemical elements, naming, discovery

In 1782 the French chemist Guyton de Morveau stated that, in the interest of science, it was necessary to have “a constant method of denomination, which helps the intelligence and relieves the memory”. Ideally, an element or a compound should have a unique name because the proliferation of names for the same substance can lead to confusion. He developed the first system of chemical nomenclature. This system was refined in collaboration with Berthollet, de Fourcroy and Lavoisier and was submitted to the French Academy in 1787. In 1813 the great Swedish chemist Jöns Jakob Berzelius proposed chemical symbols using the initials of their Latin names that was slowly adopted and then was widely used. For use in chemical formulae, each atom is represented by a unique symbol in upright type. The atomic symbol consists of one or two letters used to represent the atom in chemical formulae. Berzelius supported Lavoisier’s ideas and adapted the nomenclature to the German language, ameliorated the system and expanded it with many new terms. He determined the atomic weights of nearly all elements, and was the first to do so almost accurately. In September 1860, Dmitri Mendeleev (Fig. 1) attended the First International Chemical Congress in Karlsruhe (Germany) where 140 prominent chemists met to sort out contradictory lists of atomic and molecular weights. Mendeleev wrote Elements of Chemistry in 1868. He ranked the nearly 60 known chemical elements according to a periodic law, linking relative atomic weights of the elements to their properties. Mendeleev’s Periodic Table rapidly became the basis for understanding elements and their compounds. Undoubtedly, every schoolchild was fascinated by its first acquaintance with the “Mendeleev’s garden” and the periodicity of the properties of the elements: simplicity, coherence, rhythm, inevitability. Although the existence of a chemical industry as well as the expanding chemical knowledge and new theories at the time, the unifying and generally accepted concepts were missing.

The International Union of Pure andApplied Chemistry (IUPAC) was formed in 1919 by chemists from industry and academia with aim to serves to advance the worldwide aspects of the chemical sciences and to contribute to the application of chemistry in the service of Mankind. The primary aim of chemical nomenclature is simply to provide methodology for assigning descriptors (names and formulae) to chemical substances so that they can be identified without ambiguity, and thereby to facilitate communication. It has been accepted in the past that the discoverers of a new element has the sole right to name it. When a new element is discovered, independently confirmed, and accepted by a joint IUPAC−IUPAP (International Union of Pure and Applied Physics) Working Group, the researchers are invited to propose a name and a symbol to the IUPAC Inorganic Chemistry Division (first issue was addressed in 1947). After careful examination of the suggestion and its suitability, the IUPAC Council usually approves the name and element symbol. The exact procedure for naming newly-synthesized elements is today apparent and internationally adopted.

“Discovery of a chemical element is the experimental demonstration, beyond reasonable doubt, of the existence of a nuclide. Conformation demands reproducibility…”. Elements of atomic numbers greater than 103 are often referred to in the scientific literature but receive names only after they have been “discovered”. Names are needed for these elements even before their existence has been established and approved by IUPAC. The name is derived directly from the atomic number of the element using the following numerical roots:

The roots are put together in order of the digits which make up the atomic number and terminated by “-ium” to spell out the name, example:

104 Unq Unnilquadium

106 Unh Unnilhexium

118 Uuo Ununoctium

170 Usn Unseptnilium

For linguistic consistency, the names of all new elements should end in “-ium” according IUPAC’s element naming rules from 1953. The suffix “-on” signifies that it is a noble gas. The suffix of every metal discovered in the past 220 years is either –um or –ium. Non-metal suffixes are longstanding traditions prior to 2002, every non-metal discovered in the past 225 years has either an –on or –in suffix. Helium was an exception because it was named before any chemical investigation, after it was detected in the solar spectrum and thought to be metallic. It is desirable that the names of elements in different languages differ as little as possible, examples Table 1. But the names of the seven metals, known as the metals of Antiquity, are different.

While the origin of the names of some elements is obscure (such as antimony) and is lost in antiquity, the names of others have been based on a property of the element, a mineral from which it was isolated, its place or area of discovery, a mythological character or concept, an astronomical object, or to honor an eminent scientist, Tables 2−7. In 1979 IUPAC approved a systematic nomenclature for elements with atomic numbers greater than one hundred.

The elements named after “modern” celestial objects are presented in Table 2. As it is seen during 70 years (from 1968 till 1940), chemical element has not received name of such origin.

As it is seen from Fig. 2 this group of elements named after an astronomical object compiles around 6% of the elements, followed by a group of nine names that were derived from mythology or superstition, Table 3.

Nearly 100 years (from 1844) no chemical element has received a name after a mythological character till 1945 when promethium, Pm was produced at Oak Ridge National Laboratory (USA). From 1827 (when aluminium was discovered) up to now no newly discovered/synthesized element is named after a mineral or similar substance, Table 4.

Table 3. Elements named after a mythological concept or character

Table 4. Elements named after a mineral or similar substance

The rare earth elements (REs) exposed a weakness in Mendeleev’s approach and posed a challenge: each element was individual and therefore could not occupy the same position in the Periodic Table as another element. In 1902, the Czech chemist Bohuslav Brauner addressed the lack of positions for REs on Mendeleev’s period chart by extending the table downward after lanthanum, La. This odd name had a mythical sound and the REs are not only rare and precious but have special, unique qualities that no other elements have. Table 5 lists elements named after a property, as well as names constructed from other words. Carl Gustav Mosander, an assistant of Berzelius succeeded to separate a new rose-colored oxide from La2O3 in 1841. Lanthanum, La laid hidden in the mineral cerite for 36 years, Table 5. Mosander named the oxide Didymium (Greek didymos, means “twin”) because of the similarity with La. In 1843, he found that yttria (except Ce, La and didymia) contained three other oxides, a colorless (yttria), a yellow (erbia) and a rose-colored (terbia). A number of chemist did not succeed to separate Didymium until 1884, when at the age of 26 Carl Auer successfully separated the two earths and proposed the names of Pr (greenish salts) and Nd (new). Due to the exceedingly close chemical properties of lanthanoids, separating them from one another was an extremely difficult task for the chemists until now.

Marie Curie is a legendary figure of science and one of the most important women in modern human history. She became interested in the source of radioactivity that Henri Becquerel discovered coming from pitchblende ore in 1897. She found that only two elements emitted appreciable ionizing radiation, U and Th. In 1898 Marie and Pierre Curie discovered Po and Ra. They noticed that the barium fraction containing Ra glowed in the dark. Later, Pierre and a student noticed that a speck of Ra emits heat: in one hour radium is able to melt more than its own weight of ice. This was the first hint of nuclear energy. M. Curie was the first women awarded a Nobel Prize (in Physics). In 1903, she, together with her husband and Henri Becquerel received this recognition for their investigations on the radiation phenomena. From her 1911 Nobel Lecture, it is evident that by mastering chemistry and radioactivity, she pioneered the concept of the “atom” and the state of the art of this “new science”, today known as radiochemistry. In addition, Marie and Pierre Curie’s daughter Irène and her husband, Frédéric Joliot, discovered artificial radioactivity and were awarded the Nobel Prize in 1935 in “recognition of their synthesis of new radioactive elements”. They irradiated light elements, such as aluminium, with alpha rays from a polonium source. Some times they obtained a proton and in others a neutron and (separately) a positron. The results for aluminium can be summarized by the equations: 27Al13 + 4He2 → 30P15 +1no,

30P15 is radioactive and decays emitting a positron 30P15 →30Si14 + oe+1.

Elements named after color (Cr, Mn (Figures 4−7), Cl, I, Rh, Ir, Cs, Rb, Tl, In) are listed also in Table 5.

The suggested name by André Ampere in 1813 for an as-yet-unisolated element fluorine, F derived from the mineral fluorospar. Chlorine (Cl), bromine (Br) and iodine (I) were named from Greek adjectives describing a property but fluorospar was a source. After a century the tradition was remembered with the origin of the name of At, Table 5.

Within 15 years, three elements predicted by Mendeleev were discovered and named after the countries of discovery, and found to precisely match the predicted properties: 21 eka-Boron, Sc; 31 eka-Aluminium, Ga and 32 eka-Silicon, Ge, Table 6. The name polonium, proposed on 13 July 1898, has a provocative significance because Poland has disappeared as a state in 1795, being divided between Prussia, Russia and the Austrian Empire. Four countries situated in Europe have chemical elements named after their lands i.e. Fr, Ga, Ge, Po and Ru. So, France has not only two elements but its capital Paris (Lutetia) also give the name of element with number 71 in the Periodic Table. Another two elements (Ho and Hf) were named after European capitals of Sweden and Denmark respectively.

The three recognized laboratories (the Lawrence Berkeley Laboratory in California, the Joint Institute for Nuclear Research (JINR) in Dubna, Russia and Gesellschaft für Schwerionen Forschung in Darmstadt, Germany (Institute for Heavy Ion Research, IHIR)) have significant and indisputable contributions in synthesizing several transfermium elements and have the benefit to named chemical elements in its honor (Bk, Db and Ds), Table 6.

The first two elements in Table 7, Sm and Gd were named for minerals, which had been named for Finnish chemist Johan Gadolin (yttria ore was renamed gadolinite in his honor) and the chief of staff of the Russian Corps of Mining Engineers, Vasilii von Samarski. The editor of Science stated that when Jean-Charles Galissard de Marignac chose the name gadolinium for the newly discovered element in 1886, he did not give any reason for the selection. The next element to be named after a human being directly or more correctly to say persons was curium, Cm. It was first produced and identified by the group of Seaborg at the University of California, Berkeley: 239 94Pu + 42He→24296Cm + 01n. Thereafter (1944), naming an element after a famous scientist became an accepted and common option. Although, the first great debate without favourable decision was on the naming of the future element 43 at this time (after Henry Mosely): Ms, moseleyum.

Röntgen was awarded the first Nobel Prize in physics in 1901. He discovered almost all the properties of X-rays within the first few weeks of his investigation, and the temporary name he used for the sake of brevity remains still today.

Ernest Rutherford was awarded the Nobel Prize in chemistry in 1908. In 1911, he concluded that the atom contains a very small “nucleus” where almost all its mass is concentrated; the nucleous should carry the positive charges, whereas it is surrounded by negatively charged electrons. Rutherford’s comment on the gold foil experiment: “It was quite the most incredible event that has ever happened to me in my life. It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you.” F. Soddy and E. Rutherford proposed a theory of radioactivity in 1902 and used the term transmutation to describe the spontaneous disintegration of radioactive elements into new elements at a rate characteristic for each element. The word “radioactivity” was first coined by Marie Curie. In 1913 Soddy proposed that an element emitting an alpha particle is transmuted into the element two spaces to left on the periodic table, whereas an element emitting a beta particle is transmuted into the element immediately to the right, as consequence this led to Soddy’s proposal of isotopes. For his contributions for understanding radioactive decay and proposing isotopes he was awarded the 1921 Nobel Prize for chemistry.

Niels Bohr also received the Nobel Prize in 1922 in physics for his contributions to atomic structure, nuclear theory and radiation. The discoverers of element 107 (Darmstadt Laboratory) had a wish to call it nielsbohrium (too long and includes the first and family name of the scientist) without precedent till then and the preposition of course was not accepted).

Earnest Lawrence and Stanly Livingston invented the cyclotron at the University of California, Berkeley in 1931. Later the laboratory was named Lawrence Berkeley and many artificial elements were produced there. It is noteworthy that six of the people (Lawrence, Fermi, Bohr, Einstein, Meitner, Seaborg) connected with or working on the top secret Manhattan project for USA to produce “a powerful bomb” now have elements named in their honor. The Austrian, later Swedish physicist, Lise Meitner, born in a Jewish family, worked on radioactivity. Radioactivity is a sensitive quantity and is detectable from very small amounts of material. Element 109, meitnerium, Mt is named in her honor, and, and together with Marie Curie, became the second female scientist who was recognized in the Periodic Table. In 1917, she and Otto Hahn discovered the first long-lived isotope of the element protactinium. On 15 November 1945, the Royal Swedish Academy of Sciences announced that Hahn had been awarded the 1944 Nobel Prize in chemistry “for his discovery of the fission of heavy atomic nuclei”: the first bomb was dropped on 6 August 1945 (Hiroshima). McMillan and Seaborg shared the 1951 Nobel Chemistry Prize for discoveries in the chemistry of the transuranium elements. After World War II, under Seaborg’s direction, teams in California, Berkely obtained Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No and Lr. In June 1974, a research team led by Ghiorso reported creating an isotope of element 106 with confirmed synthesis in 1994 by the team of D. C. Hoffman. Although three years continues the debate of priority for discovery of several elements including whether it is appropriate to name a chemical element for a living chemist (Sg), contending that a living person’s accomplishments cannot be assessed from “the perspective of history”. Seaborg and his colleagues argued that the precedent had been set by Es and Fm, but the both eminent scientist deceased before the official approving of the element names.

The Periodic Table now has 114 chemical elements (and the existence of 113 and 115 is already approved) and the search for new ones continues, certainly, in keeping with tradition, history and chemistry when choosing an appropriate name of the future new elements.

Acknowledgements The author is grateful to FP7-PEOPLE-Marie Curie Actions-IEF for the financial support of the project INNOVILLN (622906) 2014-2016. The financial support by the EU Social Fund and Ministry of Education and Science, EU operational program “Development of human resources”, project BG051PO001-3.3.07-0002 Student Practices is gratefully acknowledged also. I also thank the three second-year undergraduate students (S. Angelova, A. Petrova, I. Nikolchina) from the University of Chemical Technology and Metallurgy for assistance.

NOTES

1. Wikipedia

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