Difference between revisions of "Thulium" - New World Encyclopedia
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{{Elementbox_header | number=69 | symbol=Tm | name=thulium | left=[[erbium]] | right=[[ytterbium]] | above=- | below=[[mendelevium|Md]] | color1=#ffbfff | color2=black }} | {{Elementbox_header | number=69 | symbol=Tm | name=thulium | left=[[erbium]] | right=[[ytterbium]] | above=- | below=[[mendelevium|Md]] | color1=#ffbfff | color2=black }} | ||
{{Elementbox_series | [[lanthanide]]s }} | {{Elementbox_series | [[lanthanide]]s }} | ||
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{{Elementbox_brinellhardness_mpa | 471 }} | {{Elementbox_brinellhardness_mpa | 471 }} | ||
{{Elementbox_cas_number | 7440-30-4 }} | {{Elementbox_cas_number | 7440-30-4 }} | ||
− | {{Elementbox_isotopes_begin | color1=#ffbfff | color2=black }} | + | {{Elementbox_isotopes_begin | isotopesof=thulium | color1=#ffbfff | color2=black }} |
{{Elementbox_isotopes_decay | mn=167 | sym=Tm | {{Elementbox_isotopes_decay | mn=167 | sym=Tm | ||
| na=[[synthetic radioisotope|syn]] | hl=[[1 E5 s|9.25 d]] | | na=[[synthetic radioisotope|syn]] | hl=[[1 E5 s|9.25 d]] | ||
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{{Elementbox_footer | color1=#ffbfff | color2=black }} | {{Elementbox_footer | color1=#ffbfff | color2=black }} | ||
− | '''Thulium''' ( | + | '''Thulium''' (chemical symbol '''Tm''', [[atomic number]] 69) is the least abundant of the [[rare earth]] [[metal]]s. It has a bright, silvery-gray luster. |
− | == | + | == Occurrence == |
− | + | ||
− | + | The element is never found in nature in pure form, but it is found in small quantities in [[mineral]]s with other rare earths. It is principally extracted from [[monazite]] (~0.007% thulium) ores found in river sands through [[ion-exchange]]. Newer ion-exchange and solvent extraction techniques have led to easier separation of the rare earths, which has yielded much lower costs for thulium production. The metal can be isolated through [[redox|reduction]] of its [[oxide]] with [[lanthanum]] metal or by [[calcium]] reduction in a closed container. None of thulium's [[compound (chemistry)|compound]]s are commercially important. | |
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== History == | == History == | ||
+ | |||
Thulium was [[discovery of the chemical elements|discovered]] by Swedish chemist [[Per Teodor Cleve]] in [[1879]] by looking for impurities in the [[oxide]]s of other rare earth elements (this was the same method [[Carl Gustaf Mosander]] earlier used to discover some other rare earth elements). Cleve started by removing all of the known contaminants of [[erbia]] ([[erbium|Er]]<sub>2</sub>[[oxygen|O]]<sub>3</sub>) and upon additional processing, obtained two new substances; one brown and one green. The brown substance turned out to be the oxide of the element [[holmium]] and was named [[holmia]] by Cleve and the green substance was the oxide of an unknown element. Cleve named the oxide [[thulia]] and its element thulium after [[Thule]], Scandinavia. | Thulium was [[discovery of the chemical elements|discovered]] by Swedish chemist [[Per Teodor Cleve]] in [[1879]] by looking for impurities in the [[oxide]]s of other rare earth elements (this was the same method [[Carl Gustaf Mosander]] earlier used to discover some other rare earth elements). Cleve started by removing all of the known contaminants of [[erbia]] ([[erbium|Er]]<sub>2</sub>[[oxygen|O]]<sub>3</sub>) and upon additional processing, obtained two new substances; one brown and one green. The brown substance turned out to be the oxide of the element [[holmium]] and was named [[holmia]] by Cleve and the green substance was the oxide of an unknown element. Cleve named the oxide [[thulia]] and its element thulium after [[Thule]], Scandinavia. | ||
− | == | + | == Notable characteristics == |
− | + | ||
+ | In the [[periodic table]], thulium is a member of the [[lanthanide]] group of [[inner transition element]]s. It is easy to work and can be cut by a knife. It is [[ductile]] and is somewhat resistant to [[corrosion]] in dry air. Naturally occurring thulium is made entirely of the [[stable isotope]] Tm-169. | ||
+ | |||
+ | === Isotopes === | ||
− | |||
Naturally occurring thulium is composed of 1 stable [[isotope]], Tm-169 (100% [[natural abundance]]). 31 [[radioisotope]]s have been characterized, with the most stable being Tm-171 with a [[half-life]] of 1.92 years, Tm-170 with a half-life of 128.6 days, Tm-168 with a half-life of 93.1 days, and Tm-167 with a half-life of 9.25 days. All of the remaining [[radioactive]] isotopes have half-lifes that are less than 64 hours, and the majority of these have half lifes that are less than 2 minutes. This element also has 14 [[meta state]]s, with the most stable being Tm-164m (t<sub>½</sub> 5.1 minutes), Tm-160m (t<sub>½</sub> 74.5 seconds) and Tm-155m (t<sub>½</sub> 45 seconds). | Naturally occurring thulium is composed of 1 stable [[isotope]], Tm-169 (100% [[natural abundance]]). 31 [[radioisotope]]s have been characterized, with the most stable being Tm-171 with a [[half-life]] of 1.92 years, Tm-170 with a half-life of 128.6 days, Tm-168 with a half-life of 93.1 days, and Tm-167 with a half-life of 9.25 days. All of the remaining [[radioactive]] isotopes have half-lifes that are less than 64 hours, and the majority of these have half lifes that are less than 2 minutes. This element also has 14 [[meta state]]s, with the most stable being Tm-164m (t<sub>½</sub> 5.1 minutes), Tm-160m (t<sub>½</sub> 74.5 seconds) and Tm-155m (t<sub>½</sub> 45 seconds). | ||
The isotopes of thulium range in [[atomic weight]] from 145.966 [[atomic mass unit|u]] (Tm-146) to 176.949 u (Tm-177). The primary [[decay mode]] before the most abundant stable isotope, Tm-169, is [[electron capture]], and the primary mode after is [[beta emission]]. The primary [[decay product]]s before Tm-169 are element 68 ([[erbium]]) isotopes, and the primary products after are element 70 ([[ytterbium]]) isotopes. | The isotopes of thulium range in [[atomic weight]] from 145.966 [[atomic mass unit|u]] (Tm-146) to 176.949 u (Tm-177). The primary [[decay mode]] before the most abundant stable isotope, Tm-169, is [[electron capture]], and the primary mode after is [[beta emission]]. The primary [[decay product]]s before Tm-169 are element 68 ([[erbium]]) isotopes, and the primary products after are element 70 ([[ytterbium]]) isotopes. | ||
+ | |||
+ | == Applications == | ||
+ | |||
+ | Thulium has been used to create [[laser]]s but high production costs have prevented other commercial uses from being developed. Other applications, real and potential, include: | ||
+ | *When stable thulium (Tm-169) is bombarded in a [[nuclear reactor]] it can later serve as a [[Radioactive decay|radiation]] source in portable [[x-ray]] devices. | ||
+ | *The unstable isotope Tm-171 could possibly be used as an energy source. | ||
+ | *Tm-169 has potential use in ceramic magnetic materials called [[Ferrite (magnet)|ferrite]]s, which are used in [[microwave]] equipment. | ||
== Precautions == | == Precautions == | ||
+ | |||
Thulium has a low-to-moderate acute [[toxic]] rating and should be handled with care. Metallic thulium in dust form presents a fire and explosion hazard. | Thulium has a low-to-moderate acute [[toxic]] rating and should be handled with care. Metallic thulium in dust form presents a fire and explosion hazard. | ||
+ | ==See also== | ||
+ | |||
+ | * [[Chemical element]] | ||
+ | * [[Inner transition metal]] | ||
+ | * [[Periodic table]] | ||
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* [[:Category:Thulium compounds|Thulium compounds]].'' | * [[:Category:Thulium compounds|Thulium compounds]].'' | ||
+ | == References == | ||
+ | |||
+ | * [http://periodic.lanl.gov/elements/69.html Thulium] Los Alamos National Laboratory, Chemistry Division: Periodic Table. | ||
+ | |||
+ | * Chang, Raymond (2006). ''Chemistry'' (ninth ed.) New York: McGraw-Hill Science/Engineering/Math. ISBN 0073221031. | ||
+ | |||
+ | * Greenwood, N.N.; and Earnshaw, A. (1998). ''Chemistry of the Elements'' (2nd Edition). Oxford, U.K.; Burlington, Massachusetts: Butterworth-Heinemann, Elsevier Science. ISBN 0750633654. [http://www.knovel.com/knovel2/Toc.jsp?BookID=402&VerticalID=0 Online version]. | ||
+ | |||
+ | * Cotton, F. Albert; and Wilkinson, Geoffrey (1980). ''Advanced Inorganic Chemistry'' (4th ed.), New York, NY: Wiley. ISBN 0-471-02775-8. | ||
+ | |||
+ | * Stwertka, Albert (1998). ''Guide to the Elements'', Revised Edition. Oxford, UK: Oxford University Press. ISBN 0-19-508083-1. | ||
− | + | * [http://education.jlab.org/itselemental/ele069.html Thulium] It's Elemental | |
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− | * [http://education.jlab.org/itselemental/ele069.html It's Elemental | ||
== External links == | == External links == | ||
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+ | * [http://www.webelements.com/webelements/elements/text/Tm/index.html Thulium] WebElements.com. | ||
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+ | [[Category:Physical sciences]] | ||
+ | [[Category:Chemistry]] | ||
[[Category:Chemical elements]] | [[Category:Chemical elements]] | ||
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Revision as of 00:31, 7 February 2007
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General | |||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Name, Symbol, Number | thulium, Tm, 69 | ||||||||||||||||||||||||||||||||||||
Chemical series | lanthanides | ||||||||||||||||||||||||||||||||||||
Group, Period, Block | n/a, 6, f | ||||||||||||||||||||||||||||||||||||
Appearance | silvery gray | ||||||||||||||||||||||||||||||||||||
Atomic mass | 168.93421(2) g/mol | ||||||||||||||||||||||||||||||||||||
Electron configuration | [Xe] 4f13 6s2 | ||||||||||||||||||||||||||||||||||||
Electrons per shell | 2, 8, 18, 31, 8, 2 | ||||||||||||||||||||||||||||||||||||
Physical properties | |||||||||||||||||||||||||||||||||||||
Phase | solid | ||||||||||||||||||||||||||||||||||||
Density (near r.t.) | 9.32 g/cm³ | ||||||||||||||||||||||||||||||||||||
Liquid density at m.p. | 8.56 g/cm³ | ||||||||||||||||||||||||||||||||||||
Melting point | 1818 K (1545 °C, 2813 °F) | ||||||||||||||||||||||||||||||||||||
Boiling point | 2223 K (1950 °C, 3542 °F) | ||||||||||||||||||||||||||||||||||||
Heat of fusion | 16.84 kJ/mol | ||||||||||||||||||||||||||||||||||||
Heat of vaporization | 247 kJ/mol | ||||||||||||||||||||||||||||||||||||
Heat capacity | (25 °C) 27.03 J/(mol·K) | ||||||||||||||||||||||||||||||||||||
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Atomic properties | |||||||||||||||||||||||||||||||||||||
Crystal structure | hexagonal | ||||||||||||||||||||||||||||||||||||
Oxidation states | 3 (basic oxide) | ||||||||||||||||||||||||||||||||||||
Electronegativity | 1.25 (Pauling scale) | ||||||||||||||||||||||||||||||||||||
Ionization energies (more) |
1st: 596.7 kJ/mol | ||||||||||||||||||||||||||||||||||||
2nd: 1160 kJ/mol | |||||||||||||||||||||||||||||||||||||
3rd: 2285 kJ/mol | |||||||||||||||||||||||||||||||||||||
Atomic radius | 175 pm | ||||||||||||||||||||||||||||||||||||
Atomic radius (calc.) | 222 pm | ||||||||||||||||||||||||||||||||||||
Miscellaneous | |||||||||||||||||||||||||||||||||||||
Magnetic ordering | no data | ||||||||||||||||||||||||||||||||||||
Electrical resistivity | (r.t.) (poly) 676 nΩ·m | ||||||||||||||||||||||||||||||||||||
Thermal conductivity | (300 K) 16.9 W/(m·K) | ||||||||||||||||||||||||||||||||||||
Thermal expansion | (r.t.) (poly) 13.3 µm/(m·K) | ||||||||||||||||||||||||||||||||||||
Speed of sound (thin rod) | (r.t.) 74.0 m/s | ||||||||||||||||||||||||||||||||||||
Shear modulus | 30.5 GPa | ||||||||||||||||||||||||||||||||||||
Bulk modulus | 44.5 GPa | ||||||||||||||||||||||||||||||||||||
Poisson ratio | 0.213 | ||||||||||||||||||||||||||||||||||||
Vickers hardness | 520 MPa | ||||||||||||||||||||||||||||||||||||
Brinell hardness | 471 MPa | ||||||||||||||||||||||||||||||||||||
CAS registry number | 7440-30-4 | ||||||||||||||||||||||||||||||||||||
Notable isotopes | |||||||||||||||||||||||||||||||||||||
|
Thulium (chemical symbol Tm, atomic number 69) is the least abundant of the rare earth metals. It has a bright, silvery-gray luster.
Occurrence
The element is never found in nature in pure form, but it is found in small quantities in minerals with other rare earths. It is principally extracted from monazite (~0.007% thulium) ores found in river sands through ion-exchange. Newer ion-exchange and solvent extraction techniques have led to easier separation of the rare earths, which has yielded much lower costs for thulium production. The metal can be isolated through reduction of its oxide with lanthanum metal or by calcium reduction in a closed container. None of thulium's compounds are commercially important.
History
Thulium was discovered by Swedish chemist Per Teodor Cleve in 1879 by looking for impurities in the oxides of other rare earth elements (this was the same method Carl Gustaf Mosander earlier used to discover some other rare earth elements). Cleve started by removing all of the known contaminants of erbia (Er2O3) and upon additional processing, obtained two new substances; one brown and one green. The brown substance turned out to be the oxide of the element holmium and was named holmia by Cleve and the green substance was the oxide of an unknown element. Cleve named the oxide thulia and its element thulium after Thule, Scandinavia.
Notable characteristics
In the periodic table, thulium is a member of the lanthanide group of inner transition elements. It is easy to work and can be cut by a knife. It is ductile and is somewhat resistant to corrosion in dry air. Naturally occurring thulium is made entirely of the stable isotope Tm-169.
Isotopes
Naturally occurring thulium is composed of 1 stable isotope, Tm-169 (100% natural abundance). 31 radioisotopes have been characterized, with the most stable being Tm-171 with a half-life of 1.92 years, Tm-170 with a half-life of 128.6 days, Tm-168 with a half-life of 93.1 days, and Tm-167 with a half-life of 9.25 days. All of the remaining radioactive isotopes have half-lifes that are less than 64 hours, and the majority of these have half lifes that are less than 2 minutes. This element also has 14 meta states, with the most stable being Tm-164m (t½ 5.1 minutes), Tm-160m (t½ 74.5 seconds) and Tm-155m (t½ 45 seconds).
The isotopes of thulium range in atomic weight from 145.966 u (Tm-146) to 176.949 u (Tm-177). The primary decay mode before the most abundant stable isotope, Tm-169, is electron capture, and the primary mode after is beta emission. The primary decay products before Tm-169 are element 68 (erbium) isotopes, and the primary products after are element 70 (ytterbium) isotopes.
Applications
Thulium has been used to create lasers but high production costs have prevented other commercial uses from being developed. Other applications, real and potential, include:
- When stable thulium (Tm-169) is bombarded in a nuclear reactor it can later serve as a radiation source in portable x-ray devices.
- The unstable isotope Tm-171 could possibly be used as an energy source.
- Tm-169 has potential use in ceramic magnetic materials called ferrites, which are used in microwave equipment.
Precautions
Thulium has a low-to-moderate acute toxic rating and should be handled with care. Metallic thulium in dust form presents a fire and explosion hazard.
See also
- Thulium compounds.
ReferencesISBN links support NWE through referral fees
- Thulium Los Alamos National Laboratory, Chemistry Division: Periodic Table.
- Chang, Raymond (2006). Chemistry (ninth ed.) New York: McGraw-Hill Science/Engineering/Math. ISBN 0073221031.
- Greenwood, N.N.; and Earnshaw, A. (1998). Chemistry of the Elements (2nd Edition). Oxford, U.K.; Burlington, Massachusetts: Butterworth-Heinemann, Elsevier Science. ISBN 0750633654. Online version.
- Cotton, F. Albert; and Wilkinson, Geoffrey (1980). Advanced Inorganic Chemistry (4th ed.), New York, NY: Wiley. ISBN 0-471-02775-8.
- Stwertka, Albert (1998). Guide to the Elements, Revised Edition. Oxford, UK: Oxford University Press. ISBN 0-19-508083-1.
- Thulium It's Elemental
External links
- Thulium WebElements.com.
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