Georges Urbain

Georges Urbain (12 April 1872 – 5 November 1938 in Paris) French chemist, professor of Sorbonne. He studied at the elite École supérieure de physique et de chimie industrielles de la ville de Paris (ESPCI ParisTech).[1] He discovered the element lutetium (atomic number 71) independently in 1907-08.

Georges Urbain
Solvay conference, 1922
BornApril 12, 1872
DiedNovember 5, 1938 (aged 66)
Known fordiscovery of Lutetium
claimed discovery of Celtium


  • Russell, A. S. (1940). "Georges urbain (1872–1938)". Journal of the Society of Chemical Industry. 59 (20): 343. doi:10.1002/jctb.5000592003.
  • Bram, G; Jacques, J (1997). "Georges Urbain(1872–1938) et l'unification des théories chimiques". Comptes Rendus de l'Académie des Sciences, Série IIB. 325: 27. Bibcode:1997CRASB.325...27B. doi:10.1016/S1251-8069(97)83260-5.
  • Davis, Tenney L. (November 1940). "Georges Urbain (1872-1938)". Proceedings of the American Academy of Arts and Sciences. 74 (6): 160. ISSN 0199-9818. JSTOR 20023387.
  • Weeks, Mary Elvira (1932). "The discovery of the elements: XVI. The rare earth elements". Journal of Chemical Education. 9 (10): 1751–1773. Bibcode:1932JChEd...9.1751W. doi:10.1021/ed009p1751.
  1. ^ ESPCI ParisTech Alumni 1893
1907 in science

The year 1907 in science and technology involved some significant events, listed below.

Chimie ParisTech

Chimie ParisTech (officially École nationale supérieure de chimie de Paris (National Chemical Engineering Institute in Paris), also known as ENSCP or Chimie Paris), founded in 1896 within the University of Paris, is an engineering school and a constituent college of PSL Research University specialised in chemical science. It is located in the 5th arrondissement of Paris.

The students enter the school after highly competitive exams known as the Concours Communs Polytechniques, following at least two years of classes préparatoires. The school is known as France's most selective chemical engineering collegeThe school is a research center hosting ten laboratories which conduct high level research in various fields of chemistry.

Commission on Isotopic Abundances and Atomic Weights

The Commission on Isotopic Abundances and Atomic Weights (CIAAW) is an international scientific committee of the International Union of Pure and Applied Chemistry (IUPAC) under its Division of Inorganic Chemistry. Since 1899, it is entrusted with periodic critical evaluation of atomic weights of chemical elements and other cognate data, such as the isotopic composition of elements. The biennial CIAAW Standard Atomic Weights are accepted as the authoritative source in science and appear worldwide on the periodic table wall charts.The use of CIAAW Standard Atomic Weights is also required legally, for example, in calculation of calorific value of natural gas (ISO 6976:1995), or in gravimetric preparation of primary reference standards in gas analysis (ISO 6142:2006). In addition, the current definition of kelvin, the SI unit for thermodynamic temperature, makes direct reference to the isotopic composition of oxygen and hydrogen as recommended by CIAAW. The latest CIAAW report was published in February 2016. After 20 May 2019 a new definition for kelvin will come into force based on the Boltzmann constant.


ESPCI Paris (officially the École supérieure de physique et de chimie industrielles de la Ville de Paris; The City of Paris Industrial Physics and Chemistry Higher Educational Institution) is an institution of higher education founded in 1882 by the city of Paris, France. It educates undergraduate and graduate students in physics, chemistry and biology and conducts high-level research in those fields. It is ranked as the first French École d'Ingénieurs in the 2017 Shanghai Ranking.ESPCI Paris is a constituent college of PSL Research University and a founding member of the ParisTech (Paris Institute of Technology) alliance.

5 researchers and alumni from ESPCI Paris have been awarded the Nobel Prize:

Pierre and Marie Curie (Physics, 1903),

Marie Curie - second Nobel Prize (Chemistry, 1911),

Frédéric Joliot-Curie (Chemistry, 1935),

Pierre-Gilles de Gennes (Physics, 1991),

Georges Charpak (Physics, 1992).Two thirds of the students enter the School following a competitive examination (concours X-ESPCI-ENS) following at least two years of Classes Préparatoires. The other students are recruited by submitting applications. The School itself is also known as Physique-Chimie or simply PC.

ESPCI Paris nurtures relationships with many industrial partners such as Schlumberger, Rhodia, Total, Thales, Arkema, Michelin, Withings, which sponsors groups of students and has research contracts with ESPCI laboratories. ESPCI Paris also has partnerships with L'Oréal and Saint-Gobain for professional recruitment.


Erbium is a chemical element with symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare earth element, originally found in the gadolinite mine in Ytterby in Sweden, from which it got its name.

Erbium's principal uses involve its pink-colored Er3+ ions, which have optical fluorescent properties particularly useful in certain laser applications. Erbium-doped glasses or crystals can be used as optical amplification media, where Er3+ ions are optically pumped at around 980 or 1480 nm and then radiate light at 1530 nm in stimulated emission. This process results in an unusually mechanically simple laser optical amplifier for signals transmitted by fiber optics. The 1550 nm wavelength is especially important for optical communications because standard single mode optical fibers have minimal loss at this particular wavelength.

In addition to optical fiber amplifier-lasers, a large variety of medical applications (i.e. dermatology, dentistry) rely on the erbium ion's 2940 nm emission (see Er:YAG laser) when lit at another wavelength, which is highly absorbed in water in tissues, making its effect very superficial. Such shallow tissue deposition of laser energy is helpful in laser surgery, and for the efficient production of steam which produces enamel ablation by common types of dental laser.

Erbium(III) oxide

Erbium(III) oxide, is synthesized from the lanthanide metal erbium. It was partially isolated by Carl Gustaf Mosander in 1843, and first obtained in pure form in 1905 by Georges Urbain and Charles James. It has a pink color with a cubic crystal structure. Under certain conditions erbium oxide can also have a hexagonal form.

Erbium oxide is toxic when inhaled, taken orally, or injected into the blood stream in massive amounts. The effect of erbium oxides in low concentrations on humans over long periods of time has not been determined.

Group 3 element

Group 3 is a group of elements in the periodic table. This group, like other d-block groups, should contain four elements, but it is not agreed what elements belong in the group. Scandium (Sc) and yttrium (Y) are always included, but the other two spaces are usually occupied by lanthanum (La) and actinium (Ac), or by lutetium (Lu) and lawrencium (Lr); less frequently, it is considered the group should be expanded to 32 elements (with all the lanthanides and actinides included) or contracted to contain only scandium and yttrium. When the group is understood to contain all of the lanthanides, its trivial name is the rare-earth metals.

Three group 3 elements occur naturally: scandium, yttrium, and either lanthanum or lutetium. Lanthanum continues the trend started by two lighter members in general chemical behavior, while lutetium behaves more similarly to yttrium. While the choice of lutetium would be in accordance with the trend for period 6 transition metals to behave more similarly to their upper periodic table neighbors, the choice of lanthanum is in accordance with the trends in the s-block, which the group 3 elements are chemically more similar to. They all are silvery-white metals under standard conditions. The fourth element, either actinium or lawrencium, has only radioactive isotopes. Actinium, which occurs only in trace amounts, continues the trend in chemical behavior for metals that form tripositive ions with a noble gas configuration; synthetic lawrencium is calculated and partially shown to be more similar to lutetium and yttrium. So far, no experiments have been conducted to synthesize any element that could be the next group 3 element. Unbiunium (Ubu), which could be considered a group 3 element if preceded by lanthanum and actinium, might be synthesized in the near future, it being only three spaces away from the current heaviest element known, oganesson.


Hafnium is a chemical element with symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1923, by Coster and Hevesy, making it the last stable element to be discovered. Hafnium is named after Hafnia, the Latin name for Copenhagen, where it was discovered.Hafnium is used in filaments and electrodes. Some semiconductor fabrication processes use its oxide for integrated circuits at 45 nm and smaller feature lengths. Some superalloys used for special applications contain hafnium in combination with niobium, titanium, or tungsten.

Hafnium's large neutron capture cross-section makes it a good material for neutron absorption in control rods in nuclear power plants, but at the same time requires that it be removed from the neutron-transparent corrosion-resistant zirconium alloys used in nuclear reactors.

List of chemical elements naming controversies

The currently accepted names and symbols of the chemical elements are determined by the International Union of Pure and Applied Chemistry (IUPAC), usually following recommendations by the recognized discoverers of each element. However the names of several elements have been the subject of controversies until IUPAC established an official name. In most cases the controversy was due to a priority dispute as to who first found conclusive evidence for the existence of an element, or as to what evidence was in fact conclusive.

List of chemists

This is a list of chemists. It should include those who have been important to the development or practice of chemistry. Their research or application has made significant contributions in the area of basic or applied chemistry.


Richard Abegg (1869–1910), German chemist

Frederick Abel (1827–1902), English chemist

Friedrich Accum (1769–1838), German chemist, advances in the field of gas lighting

Homer Burton Adkins (1892–1949), American chemist, known for work in hydrogenation of organic compounds

Peter Agre (born 1949), American chemist and doctor, 2003 Nobel Prize in Chemistry

Georgius Agricola (1494–1555), German scholar known as "the father of mineralogy

Arthur Aikin (1773–1855), English chemist and mineralogist

Adrien Albert (1907–1989), Australian medicinal chemist

John Albery (1936–2013), English physical chemist

Kurt Alder (1902–1958), German chemist, 1950 Nobel Prize in Chemistry

Sidney Altman (born 1939), 1989 Nobel Prize in Chemistry

Faiza Al-Kharafi (born 1946), Kuwaiti chemist and academic. She was the president of Kuwait University from 1993 to 2002, and the first woman to head a major university in the Middle East.

Christian B. Anfinsen (1916–1995), 1972 Nobel Prize in Chemistry

Angelo Angeli, Italian chemist

Octavio Augusto Ceva Antunes (1731–1810), British scientist

Anthony Joseph Arduengo, III, American chemist

Johan August Arfwedson (1792–1841), Swedish chemist

Anton Eduard van Arkel (1893–1976), Dutch chemist

Svante Arrhenius (1859–1927), Swedish chemist, one of the founders of physical chemistry

Larned B. Asprey (1919–2005), American nuclear chemist

Francis William Aston (1877–1945), 1922 Nobel Prize in Chemistry

Amedeo Avogadro (1776–1856), Italian chemist and physicist, discovered Avogadro's law


Lutetium is a chemical element with symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry air, but not in moist air. Lutetium is the last element in the lanthanide series, and it is traditionally counted among the rare earths. Lutetium is sometimes considered the first element of the 6th-period transition metals, although lanthanum is more often considered as such.

Lutetium was independently discovered in 1907 by French scientist Georges Urbain, Austrian mineralogist Baron Carl Auer von Welsbach, and American chemist Charles James. All of these researchers found lutetium as an impurity in the mineral ytterbia, which was previously thought to consist entirely of ytterbium. The dispute on the priority of the discovery occurred shortly after, with Urbain and Welsbach accusing each other of publishing results influenced by the published research of the other; the naming honor went to Urbain, as he had published his results earlier. He chose the name lutecium for the new element, but in 1949 the spelling of element 71 was changed to lutetium. In 1909, the priority was finally granted to Urbain and his names were adopted as official ones; however, the name cassiopeium (or later cassiopium) for element 71 proposed by Welsbach was used by many German scientists until the 1950s.

Lutetium is not a particularly abundant element, although it is significantly more common than silver in the earth's crust. It has few specific uses. Lutetium-176 is a relatively abundant (2.5%) radioactive isotope with a half-life of about 38 billion years, used to determine the age of minerals and meteorites. Lutetium usually occurs in association with the element yttrium and is sometimes used in metal alloys and as a catalyst in various chemical reactions. 177Lu-DOTA-TATE is used for radionuclide therapy (see Nuclear medicine) on neuroendocrine tumours. Lutetium has the highest Brinell hardness of any lanthanide, at 890–1300 MPa.

Lutetium(III) oxide

Lutetium(III) oxide, a white solid, is a cubic compound of lutetium sometimes used in the preparation of specialty glasses. It is also called lutecia. It is a lanthanide oxide, also known as a rare earth.


A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable (they can be hammered into thin sheets) or ductile (can be drawn into wires). A metal may be a chemical element such as iron, or an alloy such as stainless steel.

In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. Many elements and compounds that are not normally classified as metals become metallic under high pressures. For example, the nonmetal iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure. Equally, some materials regarded as metals can become nonmetals. Sodium, for example, becomes a nonmetal at pressure of just under two million times atmospheric pressure.

In chemistry, two elements that would otherwise qualify (in physics) as brittle metals—arsenic and antimony—are commonly instead recognised as metalloids, on account of their predominately non-metallic chemistry. Around 95 of the 118 elements in the periodic table are metals (or are likely to be such). The number is inexact as the boundaries between metals, nonmetals, and metalloids fluctuate slightly due to a lack of universally accepted definitions of the categories involved.

In astrophysics the term "metal" is cast more widely to refer to all chemical elements in a star that are heavier than the lightest two, hydrogen and helium, and not just traditional metals. A star fuses lighter atoms, mostly hydrogen and helium, into heavier atoms over its lifetime. Used in that sense, the metallicity of an astronomical object is the proportion of its matter made up of the heavier chemical elements.Metals comprise 25% of the Earth's crust and are present in many aspects of modern life. The strength and resilience of some metals has led to their frequent use in, for example, high-rise building and bridge construction, as well as most vehicles, many home appliances, tools, pipes, and railroad tracks. Precious metals were historically used as coinage, but in the modern era, coinage metals have extended to at least 23 of the chemical elements.The history of metals is thought to begin with the use of copper about 11,000 years ago. Gold, silver, iron (as meteoric iron), lead, and brass were likewise in use before the first known appearance of bronze in the 5th millennium BCE. Subsequent developments include the production of early forms of steel; the discovery of sodium—the first light metal—in 1809; the rise of modern alloy steels; and, since the end of World War II, the development of more sophisticated alloys.

Niels Bohr

Niels Henrik David Bohr (Danish: [nels ˈboɐ̯ˀ]; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research.

Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of complementarity: that items could be separately analysed in terms of contradictory properties, like behaving as a wave or a stream of particles. The notion of complementarity dominated Bohr's thinking in both science and philosophy.

Bohr founded the Institute of Theoretical Physics at the University of Copenhagen, now known as the Niels Bohr Institute, which opened in 1920. Bohr mentored and collaborated with physicists including Hans Kramers, Oskar Klein, George de Hevesy, and Werner Heisenberg. He predicted the existence of a new zirconium-like element, which was named hafnium, after the Latin name for Copenhagen, where it was discovered. Later, the element bohrium was named after him.

During the 1930s, Bohr helped refugees from Nazism. After Denmark was occupied by the Germans, he had a famous meeting with Heisenberg, who had become the head of the German nuclear weapon project. In September 1943, word reached Bohr that he was about to be arrested by the Germans, and he fled to Sweden. From there, he was flown to Britain, where he joined the British Tube Alloys nuclear weapons project, and was part of the British mission to the Manhattan Project. After the war, Bohr called for international cooperation on nuclear energy. He was involved with the establishment of CERN and the Research Establishment Risø of the Danish Atomic Energy Commission and became the first chairman of the Nordic Institute for Theoretical Physics in 1957.

Timeline of chemical element discoveries

The discovery of the 118 chemical elements known to exist as of 2019 is presented in chronological order. The elements are listed generally in the order in which each was first defined as the pure element, as the exact date of discovery of most elements cannot be accurately determined. There are plans to synthesise more elements, and it is not known how many elements are possible.

Each element's name, atomic number, year of first report, name of the discoverer, and notes related to the discovery are listed.


Urbain is a name of French origin which may refer to:

Family nameAchille Urbain (1884–1957), French biologist

Georges Urbain (1872–1938), French chemist

Ismael Urbain (1812–1884), French journalist and interpreter

Jacques Urbain, Belgian scientist

Jean-Didier Urbain (born 1951), French sociologist

Walter M. Urbain (1910–2002), American food scientistGiven nameUrbain Audibert (1789–1846), French nurseryman

Urbain Boiret (1731–1774), Canadian priest

Urbain Bouriant (1849–1903), French egyptologist

Urbain Braems (born 1933), Belgian soccer player

Urbain Cancelier (fl. 1988–2012), French comedian and actor

Urbain de Maillé-Brézé (1597–1650), French military officer and diplomat

Urbain Dubois (1818–1901), French chef

Urbain Gohier (1862–1951), French lawyer and journalist

Urbain Grandier (1590–1634), French priest

Urbain Johnson (1824 –1917), farmer and politician

Urbain de Florit de La Tour de Clamouze (1794–1868), French lay brother

Urbain Le Verrier (1811–1877), French mathematician

Urbain Lippé (1831–1896), Canadian notary and politician

Urbain Mbenga, Guinean and Congolese religious leader

Urbain Olivier (1810–1888), Swiss writerOtherMétal Urbain, French punk music group

Urbain Cote Round Barn, ND, USA


Victorium, originally named monium, is a mixture of gadolinium and terbium. In 1898, English chemist William Crookes reported his discovery of it in his inaugural address as president of the British Association for the Advancement of Science. He identified the new substance, based on an analysis of the unique phosphorescence and other ultraviolet-visible spectral phenomena, as a new chemical element, although this was later shown to be false. The name monium means "alone", because its spectral lines stood alone at the end of the ultraviolet spectrum. In 1899 Crookes renamed the purported element "victorium" in honor of Queen Victoria's recent diamond jubilee. He assigned it the symbol Vc. By 1905, however, French chemist Georges Urbain had proven that victorium was not a distinct element but rather an impurity of gadolinium.


Ytterbium is a chemical element with symbol Yb and atomic number 70. It is the fourteenth and penultimate element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state. However, like the other lanthanides, its most common oxidation state is +3, as in its oxide, halides, and other compounds. In aqueous solution, like compounds of other late lanthanides, soluble ytterbium compounds form complexes with nine water molecules. Because of its closed-shell electron configuration, its density and melting and boiling points differ significantly from those of most other lanthanides.

In 1878, the Swiss chemist Jean Charles Galissard de Marignac separated from the rare earth "erbia" another independent component, which he called "ytterbia", for Ytterby, the village in Sweden near where he found the new component of erbium. He suspected that ytterbia was a compound of a new element that he called "ytterbium" (in total, four elements were named after the village, the others being yttrium, terbium and erbium). In 1907, the new earth "lutecia" was separated from ytterbia, from which the element "lutecium" (now lutetium) was extracted by Georges Urbain, Carl Auer von Welsbach, and Charles James. After some discussion, Marignac's name "ytterbium" was retained. A relatively pure sample of the metal was not obtained until 1953. At present, ytterbium is mainly used as a dopant of stainless steel or active laser media, and less often as a gamma ray source.

Natural ytterbium is a mixture of seven stable isotopes, which altogether are present at concentrations of 3 parts per million. This element is mined in China, the United States, Brazil, and India in form of the minerals monazite, euxenite, and xenotime. The ytterbium concentration is low because it is found only among many other rare earth elements; moreover, it is among the least abundant. Once extracted and prepared, ytterbium is somewhat hazardous as an eye and skin irritant. The metal is a fire and explosion hazard.

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