thulium

thu·li·um

T0193700 (tho͞o′lē-əm)n. Symbol Tm A bright, soft, silvery, metallic element of the lanthanide series obtained commercially from the mineral monazite, having an x-ray emitting isotope that is used in portable medical x-ray units. Atomic number 69; atomic weight 168.934; melting point 1,545°C; boiling point 1,950°C; specific gravity 9.321 (at 25°C); valence 2, 3. See Periodic Table.

[After Thule¹.]

thulium

(ˈθjuːlɪəm) n (Elements & Compounds) 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[C19: New Latin, from Thule + -ium]

thu•li•um

(ˈθu li əm)

n. a rare-earth metallic element found in gadolinite and other uncommon minerals. Symbol: Tm; at. wt.: 168.934; at. no.: 69; sp. gr.: 9.32. [< French (1879), after Thule, taken as a name for ancient Scandinavia; see -ium²]

thu·li·um

(tho͞o′lē-əm) Symbol Tm A soft, easily shaped, silver-gray metallic element of the lanthanide series. An artificial radioactive isotope of thulium is used as a radiation source in small, portable x-ray machines. Atomic number 69. See Periodic Table.

Thesaurus

Noun

thulium - a soft silvery metallic element of the rare earth group; isotope 170 emits X-rays and is used in small portable X-ray machines; it occurs in monazite and apatite and xenotimeatomic number 69, Tmmetal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.apatite - a common complex mineral consisting of calcium fluoride phosphate or calcium chloride phosphate; a source of phosphorusmonazite - a reddish-brown mineral containing rare earth metals; an important source of thorium and ceriumxenotime - a brown-to-yellow mineral that is a phosphate of yttrium in crystalline form

Translations

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&degC;; b.p. 1,947&degC;; 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.
..... Click the link for more information. 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.
..... Click the link for more information. 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
..... Click the link for more information. . 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

thulium

[thoo´le-um] a chemical element, atomic number 69, atomic weight 168.934, symbol Tm. (See Appendix 6.)

thu·li·um (Tm),

(thū'lē-ŭm), A metallic element of the lanthanide series, atomic no. 69, atomic wt. l68.93421. [L. Thule, the earliest name for Scandinavia]

thu·li·um

(thū'lē-ŭm) A metallic element of the lanthanide series, atomic no. 69, atomic wt. l68.93421. [L. Thule, the earliest name for Scandinavia]

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Synonyms for thulium

noun a soft silvery metallic element of the rare earth group

Synonyms

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