thulium


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thulium

(tho͞o`lēəm) [from Thule, an ancient name for Scandinavia], metallic chemical element; symbol Tm; at. no. 69; at. wt. 168.93421; m.p. about 1,545°C;; b.p. 1,947°C;; sp. gr. 9.3; valence +3. Thulium is a soft, malleable, ductile, lustrous silver-white metal. It is one of the rare-earth metalsrare-earth metals,
in chemistry, group of metals including those of the lanthanide series and actinide series and usually yttrium, sometimes scandium and thorium, and rarely zirconium. Promethium, which is not found in nature, is not usually considered a rare-earth metal.
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 of the lanthanide serieslanthanide series,
a series of metallic elements, included in the rare-earth metals, in Group 3 of the periodic table. Members of the series are often called lanthanides, although lanthanum (atomic number 57) is not always considered a member of the series.
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 in Group 3 of the periodic tableperiodic table,
chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the table entitled
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. It does not tarnish rapidly in dry air but should be protected from moisture. It forms compounds with oxygen and the halogens, most of which are light green. The oxide, Tm2O3, is called thulia. Thulium is the least abundant of the rare-earth metals. It is found in the minerals gadolinite and euxenite and in monazite, the chief commercial source. The metal can be obtained by chemical reduction of its compounds. The pure metal and compounds have few commercial uses, but they are often used without purification in combination with the other rare-earth metals and compounds, e.g., in lighter flints and carbon electrodes for arc lighting. Although the only naturally occurring isotope (thulium-169) is stable, there are 15 unstable isotopes. Thulium-170 (half-life about 129 days), prepared by irradiating thulium-169 in a nuclear reactor, emits X rays; it is used in portable X-ray sources. Thulium was discovered in 1879 by P. T. Cleve.

thulium

[′thü·lē·əm]
(chemistry)
A rare-earth element, symbol Tm, of the lanthanide group, atomic number 69, atomic weight 168.9342; reacts slowly with water, soluble in dilute acids, melts at 1550°C, boils at 1727°C; the dust is a fire hazard; used as x-ray source and to make ferrites.

thulium

a malleable ductile silvery-grey element occurring principally in monazite. The radioisotope thulium-170 is used as an electron source in portable X-ray units. Symbol: Tm; atomic no.: 69; atomic wt.: 168.93421; valency: 3; relative density: 9.321; melting pt.: 1545°C; boiling pt.: 1950°C
References in periodicals archive ?
Thulium laser versus holmium laser transurethral enucleation of the prostate: 18-month follow-up data of a single center.
25% (21)(RCT) Rao et al 2013 NR NR (23)(RCT) RCT; randomized clinical trials, CS; case series, HoLEP; Holmium laser enucleation of the prostate, 2ndry HoLEP; after previous prostate surgery, ThulEP; Thulium laser enucleation of the prostate, Greenlight LEP; Greenlight laser enucleation of the prostate, ELEP; Eraser laser enucleation of the prostate, PKEP; Plasma kinetic enucleation of the prostate, NS; not specified, NR; not reported, NA; not applicable, PCa; prostate cancer, OC; open cystostomy; B: bilop; T: trilob; Piranha, Wolf Inc.
Thulium laser enucleation versus plasmakinetic resection of the prostate: A randomized prospective trial with 18-month follow up.
In the United States, the proportions of BPH-related surgery include monopolar TURP (73%); photoselective vaporization of the prostate (58%); TURIS-V (24%); bipolar TURP (20%); holmium laser ablation (18%); thulium laser ablation (4%) and laparoscopic or robotic prostatectomy (1% and 3%, respectively).
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Rare earth (RE) elements are a collection of seventeen chemical elements in the periodic table of the chemical elements, namely lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutecium (Lu), as well as scandium (Sc) and yttrium(Y) that are closely related to lanthanum (La).
The large calcified ceramic beak was successfully retrieved after fragmentation with a thulium laser.
Left square: Hydrogen Beryllium Boron Carbon Nitrogen Fluorine Silicon Argon Potassium Scandium Germanium Cadmium Indium Tin Xenon Barium Praseodymium Neodymium Erbium Thulium Lutetium Tantalum Rhenium Osmium Iridium Platinum Mercury Thallium Lead Actinium Thorium Protactinium Plutonium Einsteinium Seaborgium Hassium transposed, yields Right square: Lithium Oxygen Sodium Aluminium Chlorine Chromium Iron Copper Gallium Arsenic Selenium Strontium Yttrium Niobium Palladium Antimony Iodine Caesium Lanthanum Promethium Samarium Gadolinium Terbium Dysprosium Ytterbium Tungsten Gold Astatine Radon Francium Uranium Curium Nobelium Dubnium Bohrium Meitnerium
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Acquired Spectrode, LLC and its next-generation pulsed thulium doped fiber laser technology for use in advanced countermeasure defense systems
The letter bank HILMTU provides both lithium and thulium.