Ytterbium
In 1878, Swiss chemist Jean Charles Galissard de Marignac examined samples of gadolinite while working in Geneva. He found a new component within the earth then known as erbia and named it ytterbia after Ytterby, the Swedish village near where he originally found the erbium source. Marignac suspected that ytterbia was actually a compound containing a new element which he called ytterbium. Four elements eventually took their names from this single village including yttrium, terbium, and erbium alongside ytterbium itself.
The naming process became complicated decades later when French chemist Georges Urbain separated Marignac's ytterbia into two components in 1907. Urbain called one part neoytterbia and the other lutecia. Austrian chemist Carl Auer von Welsbach independently isolated these same elements around the same time but gave them different names like aldebaranium and cassiopeium. American chemist Charles James also worked on separating these elements during that period.
Urbain and Welsbach accused each other of publishing results based on the other party's work creating a significant dispute over priority. In 1909 the Commission on Atomic Mass settled the argument by granting priority to Urbain and adopting his names as official ones. The commission decided that the separation of lutetium from Marignac's ytterbium was first described by Urbain so neoytterbium reverted back to ytterbium. A relatively pure sample of the metal would not be obtained until 1953.
Ytterbium exists as three distinct crystal structures labeled alpha beta and gamma with transformation temperatures at minus thirteen degrees Celsius and seven hundred ninety-five degrees Celsius. The exact temperature for these changes depends heavily on pressure and stress conditions applied to the material. The beta allotrope measures six point nine six six grams per cubic centimeter and exists at room temperature with a face-centered cubic crystal structure.
The high-temperature gamma allotrope has a density of six point five seven grams per cubic centimeter and features a body-centered cubic crystalline structure instead. The alpha allotrope measures six point nine zero three grams per cubic centimeter and possesses a hexagonal crystalline structure stable only at low temperatures. This element has a melting point of eight hundred twenty-four degrees Celsius and a boiling point of one thousand one hundred ninety-six degrees Celsius creating the smallest liquid range of all metals.
When freshly prepared ytterbium appears less golden than cesium but remains soft malleable and ductile like other rare-earth elements. It dissolves readily in strong mineral acids while its electrical conductivity behaves differently under extreme pressure. At normal atmospheric pressure the beta allotrope conducts electricity metallically but becomes a semiconductor when exposed to about sixteen thousand atmospheres of pressure.
Ytterbium metal tarnishes slowly in air taking on a golden or brown hue over time. Finely dispersed particles oxidize quickly in air and oxygen while mixtures with polytetrafluoroethylene burn with an emerald-green flame. The element reacts with hydrogen to form various non-stoichiometric hydrides and dissolves slowly in water but quite quickly in acids liberating hydrogen gas.
Most compounds exist in the plus-three oxidation state making salts nearly colorless since the ion absorbs light in the near-infrared range rather than visible light. Ytterbium is quite electropositive reacting slowly with cold water and quite quickly with hot water to form ytterbium hydroxide. Unlike most lanthanides which almost exclusively form plus-three compounds ytterbium readily forms divalent compounds due to its fully filled f-shell providing extra stability.
The yellow-green ytterbium two-plus ion acts as a very strong reducing agent that decomposes water releasing hydrogen so only the colorless three-plus ion occurs in aqueous solution. Samarium and thulium behave similarly in their plus-two states though europium two-plus remains stable in water. Ytterbium metal behaves like europium metal and alkaline earth metals by dissolving in ammonia to form blue electride salts.
Natural ytterbium consists of seven stable isotopes including one six eight Yb through one seven six Yb with one seven four Yb being the most abundant at thirty-one point nine zero percent natural abundance. Thirty-two synthetic radioisotopes have been observed with the most stable being one six nine Yb having a half-life of thirty-two point zero one four days.
One seven five Yb has a half-life of four point one eight five days while one six six Yb lasts fifty-six point seven hours before decaying. All remaining radioactive isotopes possess half-lives shorter than two hours with the majority lasting less than twenty minutes. The element also contains eighteen meta states with the most stable being one six nine mYb which exists for forty-six seconds.
Known isotopes range from one four nine Yb to one eight seven Yb covering a wide spectrum of nuclear properties. Isotopes lighter than the most abundant stable isotope undergo electron capture giving thulium isotopes as their primary decay mode. Those heavier than one seven four Yb primarily emit beta particles resulting in lutetium isotopes instead.
Ytterbium appears with other rare-earth elements in several minerals like monazite sand containing only zero point zero three percent ytterbium by weight. It is also found in euxenite and xenotime ores across major mining areas including China the United States Brazil India Sri Lanka and Australia. Reserves are estimated at one million tonnes though the world production reaches only about fifty tonnes per year reflecting few commercial applications.
The abundance of ytterbium in Earth's crust measures approximately three milligrams per kilogram making it among the least abundant elements. As an even-numbered lanthanide it remains significantly more abundant than immediate neighbors thulium and lutetium according to the Oddo, Harkins rule. These neighboring elements occur in the same concentrate at levels of about zero point five percent each despite being chemically similar.
Separating ytterbium from other rare earths proves difficult due to its similar chemical properties requiring ion exchange or solvent extraction techniques developed during the mid to late twentieth century. Minerals such as monazite dissolve into acids like sulfuric acid before applying solutions to resin where different lanthanides bind with varying affinities. Complexing agents then dissolve the solution allowing isolation based on bonding differences.
In 2013 experimental atomic clocks using ytterbium atoms set a record for stability at the National Institute of Standards and Technology. Physicists reported these clocks tick within less than two parts in one quintillion roughly ten times better than previous best results for other atomic clock types. The clocks would remain accurate within one second for a period comparable to the age of the universe itself.
These devices rely on about ten thousand ytterbium atoms laser-cooled to ten microkelvin trapped inside optical lattices made of pancake-shaped wells created by laser light. Another laser ticks five hundred eighteen trillion times per second provoking transitions between energy levels in the atoms. The large number of atoms contributes directly to the high stability achieved by these systems.
Visible light waves oscillate faster than microwaves so optical clocks can achieve greater precision than caesium atomic clocks. A model featuring a single ytterbium ion caught in an ion trap proves highly accurate reaching exactness to seventeen digits after the decimal point. The Physikalisch-Technische Bundesanstalt continues working on several such optical clock designs today.
The Yb three-plus ion serves as doping material in active laser media specifically solid state lasers and double clad fiber lasers. These ytterbium lasers generate short pulses with long lifetimes while radiating in the one point zero three to one point twelve micrometer band depending on host materials. They are optically pumped at wavelengths ranging from nine hundred nanometers to one micrometer.
Power scaling has increased from one kilowatt regimes due to advancements in components and Yb-doped fibers achieving near perfect beam qualities at power levels exceeding two thousand watts. Low numerical aperture large mode area fibers negate impacts of nonlinear effects like stimulated Brillouin scattering limiting higher power achievements in single mode systems.
Optimization of matching passive fibers within optical cavities reduces splice losses while host glass modification improves slope efficiency and photodarkening performance. Much progress occurred in power scaling lasers and amplifiers produced with ytterbium doped optical fibers enabling broadband configurations around one thousand six hundred forty nanometers. These developments allow for distinct advantages over traditional single mode ytterbium-doped fibers regarding mode field diameter and nonlinear effect management.
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Common questions
Who discovered ytterbium and when was it named?
Swiss chemist Jean Charles Galissard de Marignac discovered ytterbium in 1878 while examining samples of gadolinite in Geneva. He named the element after Ytterby, a Swedish village near where he originally found the erbium source.
When did Georges Urbain officially separate ytterbium from other elements?
French chemist Georges Urbain separated Marignac's ytterbia into two components including neoytterbia and lutecia in 1907. The Commission on Atomic Mass granted priority to Urbain in 1909 and adopted his names as official ones.
What are the crystal structures and melting point of ytterbium metal?
Ytterbium exists as three distinct crystal structures labeled alpha beta and gamma with transformation temperatures at minus thirteen degrees Celsius and seven hundred ninety-five degrees Celsius. The element has a melting point of eight hundred twenty-four degrees Celsius and a boiling point of one thousand one hundred ninety-six degrees Celsius creating the smallest liquid range of all metals.
How many stable isotopes does natural ytterbium contain and which is most abundant?
Natural ytterbium consists of seven stable isotopes including one six eight Yb through one seven six Yb with one seven four Yb being the most abundant at thirty-one point nine zero percent natural abundance. Thirty-two synthetic radioisotopes have been observed with the most stable being one six nine Yb having a half-life of thirty-two point zero one four days.
When did experimental atomic clocks using ytterbium atoms set a record for stability?
In 2013 experimental atomic clocks using ytterbium atoms set a record for stability at the National Institute of Standards and Technology. Physicists reported these clocks tick within less than two parts in one quintillion roughly ten times better than previous best results for other atomic clock types.