Lutetium | ||||||||||||||||||||||||||||||||||||
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Pronunciation | /ljuːˈtiːʃiəm/ | |||||||||||||||||||||||||||||||||||
Appearance | silvery white | |||||||||||||||||||||||||||||||||||
Standard atomic weight Ar°(Lu) | ||||||||||||||||||||||||||||||||||||
Lutetium in the periodic table | ||||||||||||||||||||||||||||||||||||
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Atomic number (Z) | 71 | |||||||||||||||||||||||||||||||||||
Group | group 3 | |||||||||||||||||||||||||||||||||||
Period | period 6 | |||||||||||||||||||||||||||||||||||
Block | d-block | |||||||||||||||||||||||||||||||||||
Electron configuration | [ Xe ] 4f14 5d1 6s2 | |||||||||||||||||||||||||||||||||||
Electrons per shell | 2, 8, 18, 32, 9, 2 | |||||||||||||||||||||||||||||||||||
Physical properties | ||||||||||||||||||||||||||||||||||||
Phase at STP | solid | |||||||||||||||||||||||||||||||||||
Melting point | 1925 K (1652 °C,3006 °F) | |||||||||||||||||||||||||||||||||||
Boiling point | 3675 K(3402 °C,6156 °F) | |||||||||||||||||||||||||||||||||||
Density (at 20° C) | 9.840 g/cm3 [3] | |||||||||||||||||||||||||||||||||||
when liquid (at m.p.) | 9.3 g/cm3 | |||||||||||||||||||||||||||||||||||
Heat of fusion | ca. 22 kJ/mol | |||||||||||||||||||||||||||||||||||
Heat of vaporization | 414 kJ/mol | |||||||||||||||||||||||||||||||||||
Molar heat capacity | 26.86 J/(mol·K) | |||||||||||||||||||||||||||||||||||
Vapor pressure
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Atomic properties | ||||||||||||||||||||||||||||||||||||
Oxidation states | 0, [4] +1, +2, +3 (a weakly basic oxide) | |||||||||||||||||||||||||||||||||||
Electronegativity | Pauling scale: 1.27 | |||||||||||||||||||||||||||||||||||
Ionization energies |
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Atomic radius | empirical:174 pm | |||||||||||||||||||||||||||||||||||
Covalent radius | 187±8 pm | |||||||||||||||||||||||||||||||||||
Spectral lines of lutetium | ||||||||||||||||||||||||||||||||||||
Other properties | ||||||||||||||||||||||||||||||||||||
Natural occurrence | primordial | |||||||||||||||||||||||||||||||||||
Crystal structure | hexagonal close-packed (hcp)(hP2) | |||||||||||||||||||||||||||||||||||
Lattice constants | a = 350.53 pm c = 554.93 pm (at 20 °C) [3] | |||||||||||||||||||||||||||||||||||
Thermal expansion | poly: 9.9 µm/(m⋅K)(at r.t.) | |||||||||||||||||||||||||||||||||||
Thermal conductivity | 16.4 W/(m⋅K) | |||||||||||||||||||||||||||||||||||
Electrical resistivity | poly: 582 nΩ⋅m(at r.t.) | |||||||||||||||||||||||||||||||||||
Magnetic ordering | paramagnetic [5] | |||||||||||||||||||||||||||||||||||
Young's modulus | 68.6 GPa | |||||||||||||||||||||||||||||||||||
Shear modulus | 27.2 GPa | |||||||||||||||||||||||||||||||||||
Bulk modulus | 47.6 GPa | |||||||||||||||||||||||||||||||||||
Poisson ratio | 0.261 | |||||||||||||||||||||||||||||||||||
Vickers hardness | 755–1160 MPa | |||||||||||||||||||||||||||||||||||
Brinell hardness | 890–1300 MPa | |||||||||||||||||||||||||||||||||||
CAS Number | 7439-94-3 | |||||||||||||||||||||||||||||||||||
History | ||||||||||||||||||||||||||||||||||||
Naming | after Lutetia , Latin for: Paris, in the Roman era | |||||||||||||||||||||||||||||||||||
Discovery | Carl Auer von Welsbach and Georges Urbain (1906) | |||||||||||||||||||||||||||||||||||
First isolation | Carl Auer von Welsbach(1906) | |||||||||||||||||||||||||||||||||||
Named by | Georges Urbain(1906) | |||||||||||||||||||||||||||||||||||
Isotopes of lutetium | ||||||||||||||||||||||||||||||||||||
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Lutetium is a chemical element; it has 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 earth elements; it can also be classified as the first element of the 6th-period transition metals. [7]
Lutetium was independently discovered in 1907 by French scientist Georges Urbain, Austrian mineralogist Baron Carl Auer von Welsbach, and American chemist Charles James. [8] All of these researchers found lutetium as an impurity in the mineral ytterbia, which was previously thought to consist entirely of ytterbium and oxygen. 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 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. [9]
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 [10] 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. [11]
A lutetium atom has 71 electrons, arranged in the configuration [ Xe ] 4f145d16s2. [12] Lutetium is generally encountered in the 3+ oxidation state, having lost its two outermost 6s and the single 5d-electron. The lutetium atom is the smallest among the lanthanide atoms, due to the lanthanide contraction, [13] and as a result lutetium has the highest density, melting point, and hardness of the lanthanides. [14] As lutetium's 4f orbitals are highly stabilized only the 5d and 6s orbitals are involved in chemical reactions and bonding; [15] [16] thus it is characterized as a d-block rather than an f-block element, [17] and on this basis some consider it not to be a lanthanide at all, but a transition metal like its lighter congeners scandium and yttrium. [18] [19]
Lutetium's compounds almost always contain the element in the 3+ oxidation state. [20] Aqueous solutions of most lutetium salts are colorless and form white crystalline solids upon drying, with the common exception of the iodide, which is brown. The soluble salts, such as nitrate, sulfate and acetate form hydrates upon crystallization. The oxide, hydroxide, fluoride, carbonate, phosphate and oxalate are insoluble in water. [21]
Lutetium metal is slightly unstable in air at standard conditions, but it burns readily at 150 °C to form lutetium oxide. The resulting compound is known to absorb water and carbon dioxide, and it may be used to remove vapors of these compounds from closed atmospheres. [22] Similar observations are made during reaction between lutetium and water (slow when cold and fast when hot); lutetium hydroxide is formed in the reaction. [23] Lutetium metal is known to react with the four lightest halogens to form trihalides; except the fluoride they are soluble in water.
Lutetium dissolves readily in weak acids [22] and dilute sulfuric acid to form solutions containing the colorless lutetium ions, which are coordinated by between seven and nine water molecules, the average being [Lu(H2O)8.2]3+. [24]
Lutetium is usually found in the +3 oxidation state, like most other lanthanides. However, it can also be in the 0, +1 and +2 states as well.
Lutetium occurs on the Earth in form of two isotopes: lutetium-175 and lutetium-176. Out of these two, only the former is stable, making the element monoisotopic. The latter one, lutetium-176, decays via beta decay with a half-life of 3.78×1010 years; it makes up about 2.5% of natural lutetium. [6] To date, 40 synthetic radioisotopes of the element have been characterized, ranging in mass number from 149 to 190; [6] [25] the most stable such isotopes are lutetium-174 with a half-life of 3.31 years, and lutetium-173 with a half-life of 1.37 years. [6] All of the remaining radioactive isotopes have half-lives that are less than 9 days, and the majority of these have half-lives that are less than half an hour. [6] Isotopes lighter than the stable lutetium-175 decay via electron capture (to produce isotopes of ytterbium), with some alpha and positron emission; the heavier isotopes decay primarily via beta decay, producing hafnium isotopes. [6]
The element also has 43 known nuclear isomers, with masses of 150, 151, 153–162, and 166–180 (not every mass number corresponds to only one isomer). The most stable of them are lutetium-177m, with a half-life of 160.4 days, and lutetium-174m, with a half-life of 142 days; these are longer than the half-lives of the ground states of all radioactive lutetium isotopes except lutetium-173, 174, and 176. [6]
Lutetium, derived from the Latin Lutetia (Paris), was independently discovered in 1907 by French scientist Georges Urbain, Austrian mineralogist Baron Carl Auer von Welsbach, and American chemist Charles James. [26] [27] They found it as an impurity in ytterbia, which was thought by Swiss chemist Jean Charles Galissard de Marignac to consist entirely of ytterbium. [28] The scientists proposed different names for the elements: Urbain chose neoytterbium and lutecium, [29] whereas Welsbach chose aldebaranium and cassiopeium (after Aldebaran and Cassiopeia). [30] Both of these articles accused the other man of publishing results based on those of the author. [31] [32] [33] [34] [35]
The International Commission on Atomic Weights, which was then responsible for the attribution of new element names, settled the dispute in 1909 by granting priority to Urbain and adopting his names as official ones, based on the fact that the separation of lutetium from Marignac's ytterbium was first described by Urbain; [28] after Urbain's names were recognized, neoytterbium was reverted to ytterbium. An obvious issue with this decision is that Urbain was on the International Commission of Atomic Weights. [36] Until the 1950s, some German-speaking chemists called lutetium by Welsbach's name, cassiopeium; in 1949, the spelling of element 71 was changed to lutetium. The reason for this was that Welsbach's 1907 samples of lutetium had been pure, while Urbain's 1907 samples only contained traces of lutetium. [37] This later misled Urbain into thinking that he had discovered element 72, which he named celtium, which was actually very pure lutetium. The later discrediting of Urbain's work on element 72 led to a reappraisal of Welsbach's work on element 71, so that the element was renamed to cassiopeium in German-speaking countries for some time. [37] Charles James, who stayed out of the priority argument, worked on a much larger scale and possessed the largest supply of lutetium at the time. [38] Pure lutetium metal was first produced in 1953. [38]
Found with almost all other rare-earth metals but never by itself, lutetium is very difficult to separate from other elements. Its principal commercial source is as a by-product from the processing of the rare earth phosphate mineral monazite ( Ce,La,...)P O
4, which has concentrations of only 0.0001% of the element, [22] not much higher than the abundance of lutetium in the Earth crust of about 0.5 mg/kg. No lutetium-dominant minerals are currently known. [39] The main mining areas are China, United States, Brazil, India, Sri Lanka and Australia. The world production of lutetium (in the form of oxide) is about 10 tonnes per year. [38] Pure lutetium metal is very difficult to prepare. It is one of the rarest and most expensive of the rare earth metals with the price about US$10,000 per kilogram, or about one-fourth that of gold. [40] [41]
Crushed minerals are treated with hot concentrated sulfuric acid to produce water-soluble sulfates of rare earths. Thorium precipitates out of solution as hydroxide and is removed. After that the solution is treated with ammonium oxalate to convert rare earths into their insoluble oxalates. The oxalates are converted to oxides by annealing. The oxides are dissolved in nitric acid that excludes one of the main components, cerium, whose oxide is insoluble in HNO3. Several rare earth metals, including lutetium, are separated as a double salt with ammonium nitrate by crystallization. Lutetium is separated by ion exchange. In this process, rare-earth ions are adsorbed onto suitable ion-exchange resin by exchange with hydrogen, ammonium or cupric ions present in the resin. Lutetium salts are then selectively washed out by suitable complexing agent. Lutetium metal is then obtained by reduction of anhydrous LuCl 3 or LuF 3 by either an alkali metal or alkaline earth metal. [21]
177Lu is produced by neutron activation of 176Lu or by indirectly by neutron activation of 176Yb followed by beta decay. The 6.693 day half life allows transport from the production reactor to the point of use without significant loss in activity. [42]
Small quantities of lutetium have many speciality uses.
Stable lutetium can be used as catalysts in petroleum cracking in refineries and can also be used in alkylation, hydrogenation, and polymerization applications. [43]
Lutetium aluminium garnet (Al5Lu3O12) has been proposed for use as a lens material in high refractive index immersion lithography. [44] Additionally, a tiny amount of lutetium is added as a dopant to gadolinium gallium garnet, which is used in magnetic bubble memory devices. [45] Cerium-doped lutetium oxyorthosilicate is currently the preferred compound for detectors in positron emission tomography (PET). [46] [47] Lutetium aluminium garnet (LuAG) is used as a phosphor in light-emitting diode light bulbs. [48] [49]
Lutetium tantalate (LuTaO4) is the densest known stable white material (density 9.81 g/cm3) [50] and therefore is an ideal host for X-ray phosphors. [51] [52] The only denser white material is thorium dioxide, with density of 10 g/cm3, but the thorium it contains is radioactive.
Lutetium is also a compound of several scintillating materials, which convert X-rays to visible light. It is part of LYSO, LuAg and lutetium iodide scintillators.
Research indicates that lutetium-ion atomic clocks could provide greater accuracy than any existing atomic clock. [53]
The suitable half-life and decay mode made lutetium-176 used as a pure beta emitter, using lutetium which has been exposed to neutron activation, and in lutetium–hafnium dating to date meteorites. [54]
The isotope 177Lu emits low-energy beta particles and gamma rays and has a half-life around 7 days, positive characteristics for commercial applications, especially in therapeutic nuclear medicine. [42] The synthetic isotope lutetium-177 bound to octreotate (a somatostatin analogue), is used experimentally in targeted radionuclide therapy for neuroendocrine tumors. [55] Lutetium-177 is used as a radionuclide in neuroendocrine tumor therapy and bone pain palliation. [56] [57]
Lutetium (177Lu) vipivotide tetraxetan is a therapy for prostate cancer, FDA approved in 2022. [58]
Like other rare-earth metals, lutetium is regarded as having a low degree of toxicity, but its compounds should be handled with care nonetheless: for example, lutetium fluoride inhalation is dangerous and the compound irritates skin. [22] Lutetium nitrate may be dangerous as it may explode and burn once heated. Lutetium oxide powder is toxic as well if inhaled or ingested. [22]
Similarly to the other rare-earth metals, lutetium has no known biological role, but it is found even in humans, concentrating in bones, and to a lesser extent in the liver and kidneys. [38] Lutetium salts are known to occur together with other lanthanide salts in nature; the element is the least abundant in the human body of all lanthanides. [38] Human diets have not been monitored for lutetium content, so it is not known how much the average human takes in, but estimations show the amount is only about several micrograms per year, all coming from tiny amounts absorbed by plants. Soluble lutetium salts are mildly toxic, but insoluble ones are not. [38]
Europium is a chemical element; it has symbol Eu and atomic number 63. Europium is a silvery-white metal of the lanthanide series that reacts readily with air to form a dark oxide coating. It is the most chemically reactive, least dense, and softest of the lanthanide elements. It is soft enough to be cut with a knife. Europium was isolated in 1901 and named after the continent of Europe. Europium usually assumes the oxidation state +3, like other members of the lanthanide series, but compounds having oxidation state +2 are also common. All europium compounds with oxidation state +2 are slightly reducing. Europium has no significant biological role and is relatively non-toxic compared to other heavy metals. Most applications of europium exploit the phosphorescence of europium compounds. Europium is one of the rarest of the rare-earth elements on Earth.
Erbium is a chemical element; it has 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, Sweden, which is the source of the element's name.
Holmium is a chemical element; it has symbol Ho and atomic number 67. It is a rare-earth element and the eleventh member of the lanthanide series. It is a relatively soft, silvery, fairly corrosion-resistant and malleable metal. Like many other lanthanides, holmium is too reactive to be found in native form, as pure holmium slowly forms a yellowish oxide coating when exposed to air. When isolated, holmium is relatively stable in dry air at room temperature. However, it reacts with water and corrodes readily, and also burns in air when heated.
Hafnium is a chemical element; it has 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 1922, by Dirk Coster and George de Hevesy, making it one of the last two stable elements to be discovered. Hafnium is named after Hafnia, the Latin name for Copenhagen, where it was discovered.
Lanthanum is a chemical element; it has symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. Lanthanum is traditionally counted among the rare earth elements. Like most other rare earth elements, its usual oxidation state is +3, although some compounds are known with an oxidation state of +2. Lanthanum has no biological role in humans but is essential to some bacteria. It is not particularly toxic to humans but does show some antimicrobial activity.
The lanthanide or lanthanoid series of chemical elements comprises at least the 14 metallic chemical elements with atomic numbers 57–70, from lanthanum through ytterbium. In the periodic table, they fill the 4f orbitals. Lutetium is also sometimes considered a lanthanide, despite being a d-block element and a transition metal.
Neodymium is a chemical element; it has symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard, slightly malleable, silvery metal that quickly tarnishes in air and moisture. When oxidized, neodymium reacts quickly producing pink, purple/blue and yellow compounds in the +2, +3 and +4 oxidation states. It is generally regarded as having one of the most complex spectra of the elements. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach, who also discovered praseodymium. It is present in significant quantities in the minerals monazite and bastnäsite. Neodymium is not found naturally in metallic form or unmixed with other lanthanides, and it is usually refined for general use. Neodymium is fairly common—about as common as cobalt, nickel, or copper—and is widely distributed in the Earth's crust. Most of the world's commercial neodymium is mined in China, as is the case with many other rare-earth metals.
The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows ("periods") and columns ("groups"). It is an icon of chemistry and is widely used in physics and other sciences. It is a depiction of the periodic law, which states that when the elements are arranged in order of their atomic numbers an approximate recurrence of their properties is evident. The table is divided into four roughly rectangular areas called blocks. Elements in the same group tend to show similar chemical characteristics.
Terbium is a chemical element; it has the symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable, and ductile. The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with water, evolving hydrogen gas. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.
Thulium is a chemical element; it has symbol Tm and atomic number 69. It is the thirteenth element in the lanthanide series of metals. It is the second-least abundant lanthanide in the Earth's crust, after radioactively unstable promethium. It is an easily workable metal with a bright silvery-gray luster. It is fairly soft and slowly tarnishes in air. Despite its high price and rarity, thulium is used as a dopant in solid-state lasers, and as the radiation source in some portable X-ray devices. It has no significant biological role and is not particularly toxic.
Ytterbium is a chemical element; it has symbol Yb and atomic number 70. It is a metal, the fourteenth and penultimate element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state. 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, melting point and boiling point are much lower than those of most other lanthanides.
A period 6 element is one of the chemical elements in the sixth row (or period) of the periodic table of the chemical elements, including the lanthanides. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The sixth period contains 32 elements, tied for the most with period 7, beginning with caesium and ending with radon. Lead is currently the last stable element; all subsequent elements are radioactive. For bismuth, however, its only primordial isotope, 209Bi, has a half-life of more than 1019 years, over a billion times longer than the current age of the universe. As a rule, period 6 elements fill their 6s shells first, then their 4f, 5d, and 6p shells, in that order; however, there are exceptions, such as gold.
Carl Auer von Welsbach, who received the Austrian noble title of Freiherr Auer von Welsbach in 1901, was an Austrian scientist and inventor, who separated didymium into the elements neodymium and praseodymium in 1885. He was also one of three scientists to independently discover the element lutetium, separating it from ytterbium in 1907, setting off the longest priority dispute in the history of chemistry.
Praseodymium is a chemical element; it has symbol Pr and the atomic number 59. It is the third member of the lanthanide series and is considered one of the rare-earth metals. It is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.
Group 3 is the first group of transition metals in the periodic table. This group is closely related to the rare-earth elements. It contains the four elements scandium (Sc), yttrium (Y), lutetium (Lu), and lawrencium (Lr). The group is also called the scandium group or scandium family after its lightest member.
The lanthanide contraction is the greater-than-expected decrease in atomic radii and ionic radii of the elements in the lanthanide series, from left to right. It is caused by the poor shielding effect of nuclear charge by the 4f electrons along with the expected periodic trend of increasing electronegativity and nuclear charge on moving from left to right. About 10% of the lanthanide contraction has been attributed to relativistic effects.
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.
Georges Urbain was a French chemist, a professor of the Sorbonne, a member of the Institut de France, and director of the Institute of Chemistry in Paris. Much of his work focused on the rare earths, isolating and separating elements such as europium and gadolinium, and studying their spectra, their magnetic properties and their atomic masses. He discovered the element lutetium. He also studied the efflorescence of saline hydrates.
Yttrium is a chemical element; it has symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a "rare-earth element". Yttrium is almost always found in combination with lanthanide elements in rare-earth minerals and is never found in nature as a free element. 89Y is the only stable isotope and the only isotope found in the Earth's crust.
Cerium is a chemical element; it has symbol Ce and atomic number 58. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the oxidation state of +3 characteristic of the series, it also has a stable +4 state that does not oxidize water. It is considered one of the rare-earth elements. Cerium has no known biological role in humans but is not particularly toxic, except with intense or continued exposure.
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