Erbium

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,  68Er
Erbium-crop
Erbium
Pronunciation/ˈɜːrbiəm/ (UR-bee-əm)
Appearancesilvery white
Standard atomic weight Ar, std(Er)167.259(3)[1]
Erbium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson


Er

Fm
holmiumerbiumthulium
Atomic number (Z)68
Groupgroup n/a
Periodperiod 6
Blockf-block
Element category  lanthanide
Electron configuration[Xe] 4f12 6s2
Electrons per shell
2, 8, 18, 30, 8, 2
Physical properties
Phase at STPsolid
Melting point1802 K ​(1529 °C, ​2784 °F)
Boiling point3141 K ​(2868 °C, ​5194 °F)
Density (near r.t.)9.066 g/cm3
when liquid (at m.p.)8.86 g/cm3
Heat of fusion19.90 kJ/mol
Heat of vaporization280 kJ/mol
Molar heat capacity28.12 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1504 1663 (1885) (2163) (2552) (3132)
Atomic properties
Oxidation states+1, +2, +3 (a basic oxide)
ElectronegativityPauling scale: 1.24
Ionization energies
  • 1st: 589.3 kJ/mol
  • 2nd: 1150 kJ/mol
  • 3rd: 2194 kJ/mol
Atomic radiusempirical: 176 pm
Covalent radius189±6 pm
Color lines in a spectral range
Spectral lines of erbium
Other properties
Natural occurrenceprimordial
Crystal structurehexagonal close-packed (hcp)
Hexagonal close packed crystal structure for erbium
Speed of sound thin rod2830 m/s (at 20 °C)
Thermal expansionpoly: 12.2 µm/(m·K) (r.t.)
Thermal conductivity14.5 W/(m·K)
Electrical resistivitypoly: 0.860 µΩ·m (r.t.)
Magnetic orderingparamagnetic at 300 K
Magnetic susceptibility+44,300.00·10−6 cm3/mol[2]
Young's modulus69.9 GPa
Shear modulus28.3 GPa
Bulk modulus44.4 GPa
Poisson ratio0.237
Vickers hardness430–700 MPa
Brinell hardness600–1070 MPa
CAS Number7440-52-0
History
Namingafter Ytterby (Sweden), where it was mined
DiscoveryCarl Gustaf Mosander (1843)
Main isotopes of erbium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
160Er syn 28.58 h ε 160Ho
162Er 0.139% stable
164Er 1.601% stable
165Er syn 10.36 h ε 165Ho
166Er 33.503% stable
167Er 22.869% stable
168Er 26.978% stable
169Er syn 9.4 d β 169Tm
170Er 14.910% stable
171Er syn 7.516 h β 171Tm
172Er syn 49.3 h β 172Tm

Characteristics

Physical properties

Erbium(III)chloride sunlight
Erbium(III)chloride in sunlight, showing some pink fluorescence of Er+3 from natural ultraviolet.

A trivalent element, pure erbium metal is malleable (or easily shaped), soft yet stable in air, and does not oxidize as quickly as some other rare-earth metals. Its salts are rose-colored, and the element has characteristic sharp absorption spectra bands in visible light, ultraviolet, and near infrared. Otherwise it looks much like the other rare earths. Its sesquioxide is called erbia. Erbium's properties are to a degree dictated by the kind and amount of impurities present. Erbium does not play any known biological role, but is thought to be able to stimulate metabolism.[3]

Erbium is ferromagnetic below 19 K, antiferromagnetic between 19 and 80 K and paramagnetic above 80 K.[4]

Erbium can form propeller-shaped atomic clusters Er3N, where the distance between the erbium atoms is 0.35 nm. Those clusters can be isolated by encapsulating them into fullerene molecules, as confirmed by transmission electron microscopy.[5]

Chemical properties

Erbium metal tarnishes slowly in air and burns readily to form erbium(III) oxide:

4 Er + 3 O2 → 2 Er2O3

Erbium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form erbium hydroxide:

2 Er (s) + 6 H2O (l) → 2 Er(OH)3 (aq) + 3 H2 (g)

Erbium metal reacts with all the halogens:

2 Er (s) + 3 F2 (g) → 2 ErF3 (s) [pink]
2 Er (s) + 3 Cl2 (g) → 2 ErCl3 (s) [violet]
2 Er (s) + 3 Br2 (g) → 2 ErBr3 (s) [violet]
2 Er (s) + 3 I2 (g) → 2 ErI3 (s) [violet]

Erbium dissolves readily in dilute sulfuric acid to form solutions containing hydrated Er(III) ions, which exist as rose red [Er(OH2)9]3+ hydration complexes:[6]

2 Er (s) + 3 H2SO4 (aq) → 2 Er3+ (aq) + 3 SO2−
4
(aq) + 3 H2 (g)

Isotopes

Naturally occurring erbium is composed of 6 stable isotopes, 162
Er
, 164
Er
, 166
Er
, 167
Er
, 168
Er
, and 170
Er
with 166
Er
being the most abundant (33.503% natural abundance). 29 radioisotopes have been characterized, with the most stable being 169
Er
with a half-life of 9.4 d, 172
Er
with a half-life of 49.3 h, 160
Er
with a half-life of 28.58 h, 165
Er
with a half-life of 10.36 h, and 171
Er
with a half-life of 7.516 h. All of the remaining radioactive isotopes have half-lives that are less than 3.5 h, and the majority of these have half-lives that are less than 4 minutes. This element also has 13 meta states, with the most stable being 167m
Er
with a half-life of 2.269 s.[7]

The isotopes of erbium range in atomic weight from 142.9663 u (143
Er
) to 176.9541 u (177
Er
). The primary decay mode before the most abundant stable isotope, 166
Er
, is electron capture, and the primary mode after is beta decay. The primary decay products before 166
Er
are element 67 (holmium) isotopes, and the primary products after are element 69 (thulium) isotopes.[7]

History

Erbium (for Ytterby, a village in Sweden) was discovered by Carl Gustaf Mosander in 1843.[8] Mosander was working with a sample of what was thought to be the single metal oxide yttria, derived from the mineral gadolinite. He discovered that the sample contained at least two metal oxides in addition to pure yttria, which he named "erbia" and "terbia" after the village of Ytterby where the gadolinite had been found. Mosander was not certain of the purity of the oxides and later tests confirmed his uncertainty. Not only did the "yttria" contain yttrium, erbium, and terbium; in the ensuing years, chemists, geologists and spectroscopists discovered five additional elements: ytterbium, scandium, thulium, holmium, and gadolinium.[9] Erbia and terbia, however, were confused at this time. A spectroscopist mistakenly switched the names of the two elements during spectroscopy. After 1860, terbia was renamed erbia and after 1877 what had been known as erbia was renamed terbia. Fairly pure Er2O3 was independently isolated in 1905 by Georges Urbain and Charles James. Reasonably pure erbium metal was not produced until 1934 when Wilhelm Klemm and Heinrich Bommer reduced the anhydrous chloride with potassium vapor.[10] It was only in the 1990s that the price for Chinese-derived erbium oxide became low enough for erbium to be considered for use as a colorant in art glass.[11]

Occurrence

MonaziteUSGOV
Monazite sand

The concentration of erbium in the Earth crust is about 2.8 mg/kg and in the sea water 0.9 ng/L.[12] This concentration is enough to make erbium about 45th in elemental abundance in the Earth's crust.

Like other rare earths, this element is never found as a free element in nature but is found bound in monazite sand ores. It has historically been very difficult and expensive to separate rare earths from each other in their ores but ion-exchange chromatography methods[13] developed in the late 20th century have greatly brought down the cost of production of all rare-earth metals and their chemical compounds.

The principal commercial sources of erbium are from the minerals xenotime and euxenite, and most recently, the ion adsorption clays of southern China; in consequence, China has now become the principal global supplier of this element. In the high-yttrium versions of these ore concentrates, yttrium is about two-thirds of the total by weight, and erbia is about 4–5%. When the concentrate is dissolved in acid, the erbia liberates enough erbium ion to impart a distinct and characteristic pink color to the solution. This color behavior is similar to what Mosander and the other early workers in the lanthanides would have seen in their extracts from the gadolinite minerals of Ytterby.

Production

Crushed minerals are attacked by hydrochloric or sulfuric acid that transforms insoluble rare-earth oxides into soluble chlorides or sulfates. The acidic filtrates are partially neutralized with caustic soda (sodium hydroxide) to pH 3–4. 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. The solution is treated with magnesium nitrate to produce a crystallized mixture of double salts of rare-earth metals. The salts are separated by ion exchange. In this process, rare-earth ions are sorbed onto suitable ion-exchange resin by exchange with hydrogen, ammonium or cupric ions present in the resin. The rare earth ions are then selectively washed out by suitable complexing agent.[12] Erbium metal is obtained from its oxide or salts by heating with calcium at 1450 °C under argon atmosphere.[12]

Applications

Erbium-glass
Erbium-colored glass

Erbium's everyday uses are varied. It is commonly used as a photographic filter, and because of its resilience it is useful as a metallurgical additive. Other uses:

  • Used in nuclear technology in neutron-absorbing control rods.[3][14]
  • When added to vanadium as an alloy, erbium lowers hardness and improves workability.[15]
  • Erbium oxide has a pink color, and is sometimes used as a colorant for glass, cubic zirconia and porcelain. The glass is then often used in sunglasses and cheap jewelry.[15]
  • Erbium-doped optical silica-glass fibers are the active element in erbium-doped fiber amplifiers (EDFAs), which are widely used in optical communications.[16] The same fibers can be used to create fiber lasers. In order to work efficiently, erbium-doped fiber is usually co-doped with glass modifiers/homogenizers, often aluminum or phosphorus. These dopants help prevent clustering of Er-ions and transfer the energy more efficiently between the Er ions and the signal. Co-doping of optical fiber with Er and Yb is used in high-power Er/Yb fiber lasers. Erbium can also be used in erbium-doped waveguide amplifiers.[3]
  • An erbium-nickel alloy Er3Ni has an unusually high specific heat capacity at liquid-helium temperatures and is used in cryocoolers; a mixture of 65% Er3Co and 35% Er0.9Yb0.1Ni by volume improves the specific heat capacity even more.[17][18]
  • A large variety of medical applications (i.e. dermatology, dentistry) utilize erbium ion's 2940 nm emission (see Er:YAG laser), which is highly absorbed in water (absorption coefficient about 12000/cm). Such shallow tissue deposition of laser energy is necessary for laser surgery, and the efficient production of steam for laser enamel ablation in dentistry.

Biological role

Erbium does not have a biological role, but erbium salts can stimulate metabolism. Humans consume 1 milligram of erbium a year on average. The highest concentration of erbium in humans is in the bones, but there is also erbium in the human kidneys and liver.[3]

Toxicity

Erbium is slightly toxic if ingested, but erbium compounds are not toxic.[3] Metallic erbium in dust form presents a fire and explosion hazard.[19][20][21]

References

  1. ^ Meija, J.; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
  2. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  3. ^ a b c d e Emsley, John (2001). "Erbium". Nature's Building Blocks: An A-Z Guide to the Elements. Oxford, England, UK: Oxford University Press. pp. 136–139. ISBN 978-0-19-850340-8.
  4. ^ Jackson, M. (2000). "Magnetism of Rare Earth" (PDF). The IRM Quarterly. 10 (3): 1.
  5. ^ Sato, Yuta; Suenaga, Kazu; Okubo, Shingo; Okazaki, Toshiya; Iijima, Sumio (2007). "Structures of D5d-C80 and Ih-Er3N@C80 Fullerenes and Their Rotation Inside Carbon Nanotubes Demonstrated by Aberration-Corrected Electron Microscopy". Nano Letters. 7 (12): 3704. Bibcode:2007NanoL...7.3704S. doi:10.1021/nl0720152.
  6. ^ "Chemical reactions of Erbium". Webelements. Retrieved 2009-06-06.
  7. ^ a b Georges, Audi; Bersillon, O.; Blachot, J.; Wapstra, A. H. (2003). "The NUBASE Evaluation of Nuclear and Decay Properties". Nuclear Physics A. 729 (1): 3–128. Bibcode:2003NuPhA.729....3A. CiteSeerX 10.1.1.692.8504. doi:10.1016/j.nuclphysa.2003.11.001.
  8. ^ Mosander, C. G. (1843). "On the new metals, Lanthanium and Didymium, which are associated with Cerium; and on Erbium and Terbium, new metals associated with Yttria". Philosophical Magazine. 23 (152): 241–254. doi:10.1080/14786444308644728. Note: The first part of this article, which does NOT concern erbium, is a translation of: C. G. Mosander (1842) "Något om Cer och Lanthan" [Some (news) about cerium and lanthanum], Förhandlingar vid de Skandinaviske naturforskarnes tredje möte (Stockholm) [Transactions of the Third Scandinavian Scientist Conference (Stockholm)], vol. 3, pp. 387–398.
  9. ^ Piguet, Claude (2014). "Extricating erbium". Nature Chemistry. 6 (4): 370. Bibcode:2014NatCh...6..370P. doi:10.1038/nchem.1908.
  10. ^ "Facts About Erbium". Live Science. July 23, 2013. Retrieved 22 October 2018.
  11. ^ Ihde, Aaron John (1984). The development of modern chemistry. Courier Dover Publications. pp. 378–379. ISBN 978-0-486-64235-2.
  12. ^ a b c Patnaik, Pradyot (2003). Handbook of Inorganic Chemical Compounds. McGraw-Hill. pp. 293–295. ISBN 978-0-07-049439-8. Retrieved 2009-06-06.
  13. ^ Early paper on the use of displacement ion-exchange chromatography to separate rare earths: Spedding, F. H.; Powell, J. E. (1954). "A practical separation of yttrium group rare earths from gadolinite by ion-exchange". Chemical Engineering Progress. 50: 7–15.
  14. ^ Parish, Theodore A.; Khromov, Vyacheslav V.; Carron, Igor, eds. (1999). "Use of UraniumErbium and PlutoniumErbium Fuel in RBMK Reactors". Safety issues associated with Plutonium involvement in the nuclear fuel cycle. CBoston: Kluwer. pp. 121–125. ISBN 978-0-7923-5593-9.
  15. ^ a b Hammond, C. R. (2000). The Elements, in Handbook of Chemistry and Physics (81st ed.). CRC press. ISBN 978-0-8493-0481-1.
  16. ^ Becker, P. C.; Olsson, N. A.; Simpson, J. R. (1999). Erbium-doped fiber amplifiers fundamentals and technology. San Diego: Academic Press. ISBN 978-0-12-084590-3.
  17. ^ Kittel, Peter (ed.). Advances in Cryogenic Engineering. 39a.
  18. ^ Ackermann, Robert A. (1997). Cryogenic Regenerative Heat Exchangers. Springer. p. 58. ISBN 978-0-306-45449-3.
  19. ^ Haley, T. J.; Koste, L.; Komesu, N.; Efros, M.; Upham, H. C. (1966). "Pharmacology and toxicology of dysprosium, holmium, and erbium chlorides". Toxicology and Applied Pharmacology. 8 (1): 37–43. doi:10.1016/0041-008x(66)90098-6. PMID 5921895.
  20. ^ Haley, T. J. (1965). "Pharmacology and toxicology of the rare earth elements". Journal of Pharmaceutical Sciences. 54 (5): 663–70. doi:10.1002/jps.2600540502. PMID 5321124.
  21. ^ Bruce, D. W.; Hietbrink, B. E.; Dubois, K. P. (1963). "The acute mammalian toxicity of rare earth nitrates and oxides". Toxicology and Applied Pharmacology. 5 (6): 750. doi:10.1016/0041-008X(63)90067-X.

Further reading

  • Guide to the Elements – Revised Edition, Albert Stwertka (Oxford University Press; 1998), ISBN 0-19-508083-1.

External links

Carl Gustaf Mosander

Carl Gustaf Mosander (10 September 1797 – 15 October 1858) was a Swedish chemist. He discovered the elements lanthanum, erbium and terbium.

Dental laser

A dental laser is a type of laser designed specifically for use in oral surgery or dentistry.

In the United States, the use of lasers on the gums was first approved by the Food and Drug Administration in the early 1990s, and use on hard tissue like teeth or the bone of the mandible gained approval in 1996. Several variants of dental lasers are in use with different wavelengths and these mean they are better suited for different applications.

Erbium(III) bromide

Erbium(III) bromide is a chemical compound with the chemical formula ErBr3 crystal which is highly soluble in water. It is used, like other metal bromide compounds, in water treatment, chemical analysis and for certain crystal growth applications.

Erbium(III) chloride

Erbium(III) chloride, is a violet solid with the formula ErCl3. It is used in the preparation of erbium metal.

Erbium(III) iodide

Erbium iodide is an iodide of lanthanide metal Erbium.

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.

Erbium-doped waveguide amplifier

An erbium-doped waveguide amplifier (or EDWA) is a type of an optical amplifier. It is a close relative of an EDFA, Erbium-doped fiber amplifier, and in fact EDWA's basic operating principles are identical to those of the EDFA. Both of them can be used to amplify infrared light at wavelengths in optical communication bands between 1500 and 1600 nm. However, whereas an EDFA is made using a free-standing fiber, an EDWA is typically produced on a planar substrate, sometimes in ways that are very similar to the methods used in electronic integrated circuit manufacturing. Therefore, the main advantage of EDWAs over EDFAs lies in their potential to be intimately integrated with other optical components on the same planar substrate and thus making EDFAs unnecessary.

Erbium hexaboride

Erbium hexaboride (ErB6) is a rare-earth hexaboride compound, which has a calcium hexaboride crystal structure.

It is one of the fundamental compounds formed in reactions between erbium and boron. The compound is isostructural with all other reported rare-earth hexaboride compounds including lanthanum hexaboride, samarium hexaboride, and cerium hexaboride. Due to the isostructural nature of the rare-earth hexaborides and the strong interaction of boron octahedra within the crystal, these compounds show a high degree of lattice matching which suggests the possibility of doping by substituting one rare earth metal within the crystal with another. Until recently, it had been hypothesized that erbium hexaboride was unstable due to the small size of the Er3+ cation within the crystal structure when compared to the ionic radii of other rare-earth elements that form known rare-earth hexaboride compounds. It has now been demonstrated, however, that new nanoscale synthetic methods are capable of producing high-purity, stable erbium hexaboride nanowires. These wires, produced using chemical vapor deposition (CVD), have a reported lattice constant of 4.1 Å.

Erbium tetraboride

Erbium boride is a boride of the lanthanide metal erbium.It is hard and has a high melting point. Industrial applications of erbium boride include use in semiconductors, the blades of gas turbines, and the nozzles of rocket engines.

Fiber laser

A fiber laser or fibre laser is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and holmium. They are related to doped fiber amplifiers, which provide light amplification without lasing. Fiber nonlinearities, such as stimulated Raman scattering or four-wave mixing can also provide gain and thus serve as gain media for a fiber laser.

Holmium

Holmium is a chemical element with symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a rare-earth element. Holmium was discovered by Swedish chemist Per Theodor Cleve. Its oxide was first isolated from rare-earth ores in 1878. The element's name comes from Holmia, the Latin name for the city of Stockholm.

Elemental holmium is a relatively soft and malleable silvery-white metal. It is too reactive to be found uncombined in nature, but when isolated, is relatively stable in dry air at room temperature. However, it reacts with water and corrodes readily and also burns in air when heated.

Holmium is found in the minerals monazite and gadolinite and is usually commercially extracted from monazite using ion-exchange techniques. Its compounds in nature and in nearly all of its laboratory chemistry are trivalently oxidized, containing Ho(III) ions. Trivalent holmium ions have fluorescent properties similar to many other rare-earth ions (while yielding their own set of unique emission light lines), and thus are used in the same way as some other rare earths in certain laser and glass-colorant applications.

Holmium has the highest magnetic permeability of any element and therefore is used for the polepieces of the strongest static magnets. Because holmium strongly absorbs neutrons, it is also used as a burnable poison in nuclear reactors.

Holmium(III) oxide

Holmium(III) oxide, or holmium oxide is a chemical compound of a rare-earth element holmium and oxygen with the formula Ho2O3. Together with dysprosium(III) oxide (Dy2O3) holmium oxide is one of the most powerfully paramagnetic substances known. The oxide, also called holmia, occurs as a component of the related erbium oxide mineral called erbia. Typically the oxides of the trivalent lanthanides coexist in nature and separation of these components requires specialized methods. Holmium oxide is used in making specialty colored glasses. Glass containing holmium oxide and holmium oxide solutions have a series of sharp optical absorption peaks in the visible spectral range. They are therefore traditionally used as a convenient calibration standard for optical spectrophotometers.

Isotopes of erbium

Naturally occurring erbium (68Er) is composed of 6 stable isotopes, with 166Er being the most abundant (33.503% natural abundance). Thirty radioisotopes have been characterized with between 74 and 108 neutrons, or 142 to 177 nucleons, with the most stable being 169Er with a half-life of 9.4 days, 172Er with a half-life of 49.3 hours, 160Er with a half-life of 28.58 hours, 165Er with a half-life of 10.36 hours, and 171Er with a half-life of 7.516 hours. All of the remaining radioactive isotopes have half-lives that are less than 3.5 hours, and the majority of these have half-lives that are less than 4 minutes. This element also has 13 meta states, with the most stable being 167mEr (t1/2 2.269 seconds).

The isotopes of erbium range in atomic weight from 141.9723 u (142Er) to 176.9541 u (177Er). The primary decay mode before the most abundant stable isotope, 166Er, is electron capture, and the primary mode after is beta decay. The primary decay products before 166Er are holmium isotopes, and the primary products after are thulium isotopes.

Optical amplifier

An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback from the cavity is suppressed. Optical amplifiers are important in optical communication and laser physics. They are used as optical repeaters in the long distance fiberoptic cables which carry much of the world's telecommunication links.

There are several different physical mechanisms that can be used to amplify a light signal, which correspond to the major types of optical amplifiers. In doped fiber amplifiers and bulk lasers, stimulated emission in the amplifier's gain medium causes amplification of incoming light. In semiconductor optical amplifiers (SOAs), electron-hole recombination occurs. In Raman amplifiers, Raman scattering of incoming light with phonons in the lattice of the gain medium produces photons coherent with the incoming photons. Parametric amplifiers use parametric amplification.

Solid-state laser

A solid-state laser is a laser that uses a gain medium that is a solid, rather than a liquid such as in dye lasers or a gas as in gas lasers. Semiconductor-based lasers are also in the solid state, but are generally considered as a separate class from solid-state lasers (see Laser diode).

Thulium

Thulium is a chemical element with symbol Tm and atomic number 69. It is the thirteenth and third-last element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds; because it occurs so late in the series, however, the +2 oxidation state is also stabilized by the nearly full 4f shell that results. In aqueous solution, like compounds of other late lanthanides, soluble thulium compounds form coordination complexes with nine water molecules.

In 1879, the Swedish chemist Per Teodor Cleve separated from the rare earth oxide erbia another two previously unknown components, which he called holmia and thulia; these were the oxides of holmium and thulium, respectively. A relatively pure sample of thulium metal was first obtained in 1911.

Thulium is the second-least abundant of the lanthanides, after radioactively unstable promethium which is only found in trace quantities on Earth. 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 the radiation source in portable X-ray devices, and in some solid-state lasers. It has no significant biological role and is not particularly toxic.

Xenotime

Xenotime is a rare-earth phosphate mineral, the major component of which is yttrium orthophosphate (YPO4). It forms a solid solution series with chernovite-(Y) (YAsO4) and therefore may contain trace impurities of arsenic, as well as silicon dioxide and calcium. The rare-earth elements dysprosium, erbium, terbium and ytterbium, as well as metal elements such as thorium and uranium (all replacing yttrium) are the expressive secondary components of xenotime. Due to uranium and thorium impurities, some xenotime specimens may be weakly to strongly radioactive. Lithiophyllite, monazite and purpurite are sometimes grouped with xenotime in the informal "anhydrous phosphates" group. Xenotime is used chiefly as a source of yttrium and heavy lanthanide metals (dysprosium, ytterbium, erbium and gadolinium). Occasionally, gemstones are also cut from the finer xenotime crystals.

Ytterbium

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.

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.