rare earthn.

Brit.

/ˌrɛːr ˈəːθ/, U.S.

/ˌrɛ(ə)r ˈərθ/

Origin: Formed within English, by compounding. Etymons: rare adj.¹, earth n.¹

Etymology: < rare adj.¹ + earth n.¹ (see earth n.¹ 16).

Chemistry.

Originally: any of various naturally occurring oxides of elements of the lanthanide series (or †of other metallic elements). Later (now usually): any of these individual elements; = rare earth element n. at Compounds.

ΘΚΠ

the world > matter > chemistry > elements and compounds > metals > [noun] > groups > lanthanides > compounds

rare earth1863

1816 W. Phillips Outl. Mineral. & Geol. (ed. 2) 49 Analysis has proved it to be principally composed of the rare earth yttria, and the rare metal tantalium.

1826 E. Emmons Man. Mineral. 21 Barytes and Strontian may be considered as rare earths, and are chiefly found in mineral veins... They possess the greatest specific gravity of any of the earths.]

1863 H. M. Noad Man. Chem. Anal. I. iii. 71 Oxide of Yttrium (YO)... This rare earth is of a pale-yellow colour.

1878 Chem. News 13 Sept. 136/2 I found nearly one-half of the known elements represented, and separated a group of oxides belonging to the rare earths.

1893 Bull. U.S. Geol. Surv. No. 113. 45 Until..the whole group of rare earth silicates is carefully studied..it would be premature to pronounce in favor of this..structural formula.

1902 Encycl. Brit. XXVI. 710/1 Helium has since been extracted from a variety of minerals consisting of salts of uranium, yttrium, thorium and other rare earths.

1933 Discovery Jan. 1/1 Samarium has an atomic number 62 and a mass of about 150. Chemically it is a ‘rare earth’.

1968 Times 18 Oct. 16/8 The name rare earth is something of a misnomer, since many of the minerals in the family are widely distributed throughout the earth's crust.

1999 J. Hecht City of Light xi. 133 Maurer had tried to make lasers by doping glass with the rare earth europium.

Compounds

rare earth element n. any of a group of chemically similar metallic elements comprising the lanthanide series and also usually scandium and yttrium.

ΚΠ

1888 Amer. Jrnl. Sci. 136 63 Passing to the rare earth elements, the ground under our feet is less secure.

1924 J. W. Mellor Comprehensive Treat. Inorg. & Theoret. Chem. V. xxxviii. 696 The four rare earth elements—dysprosium, Dy; holmium, Ho; erbium, Er; and thulium, Tm—are considered as a family or sub-group of the yttrium elements.

1958 Optima Mar. 22b/2 Thorium occurs chiefly in association with the rare-earth elements in monazite ore.

2000 Science 29 Sept. 2326/3 The separation of individual rare earth elements is a difficult process involving solvent extraction or ion exchange.

rare earth metal n. = rare earth element n.

ΚΠ

1877 Jrnl. Chem. Soc. 31 49 (heading) The quantivalence of the rare earth-metals.

1909 Jrnl. Industr. & Engin. Chem. 1 684/1 A process for obtaining chlorine..consisting in heating at a low temperature ammonium chloride with an oxide of a rare earth metal.

1959 Nomencl. Inorg. Chem. (I.U.P.A.C.) 6 The name rare-earth metals may be used for the elements Sc, Y, and La to Lu inclusive.

1996 Economist 31 Aug. 81/1 Mixed into the glass are small amounts of certain ‘rare-earth’ metals—praseodymium, erbium and thulium—in the form of their ions.

This entry has been updated (OED Third Edition, December 2008; most recently modified version published online March 2022).

单词	rare earth
释义	rare earthn. Brit. /ˌrɛːr ˈəːθ/, U.S. /ˌrɛ(ə)r ˈərθ/ Origin: Formed within English, by compounding. Etymons: rare adj.¹, earth n.¹ Etymology: < rare adj.¹ + earth n.¹ (see earth n.¹ 16). Chemistry. Originally: any of various naturally occurring oxides of elements of the lanthanide series (or †of other metallic elements). Later (now usually): any of these individual elements; = rare earth element n. at Compounds. ΘΚΠ the world > matter > chemistry > elements and compounds > metals > [noun] > groups > lanthanides > compounds rare earth1863 1816 W. Phillips Outl. Mineral. & Geol. (ed. 2) 49 Analysis has proved it to be principally composed of the rare earth yttria, and the rare metal tantalium. 1826 E. Emmons Man. Mineral. 21 Barytes and Strontian may be considered as rare earths, and are chiefly found in mineral veins... They possess the greatest specific gravity of any of the earths.] 1863 H. M. Noad Man. Chem. Anal. I. iii. 71 Oxide of Yttrium (YO)... This rare earth is of a pale-yellow colour. 1878 Chem. News 13 Sept. 136/2 I found nearly one-half of the known elements represented, and separated a group of oxides belonging to the rare earths. 1893 Bull. U.S. Geol. Surv. No. 113. 45 Until..the whole group of rare earth silicates is carefully studied..it would be premature to pronounce in favor of this..structural formula. 1902 Encycl. Brit. XXVI. 710/1 Helium has since been extracted from a variety of minerals consisting of salts of uranium, yttrium, thorium and other rare earths. 1933 Discovery Jan. 1/1 Samarium has an atomic number 62 and a mass of about 150. Chemically it is a ‘rare earth’. 1968 Times 18 Oct. 16/8 The name rare earth is something of a misnomer, since many of the minerals in the family are widely distributed throughout the earth's crust. 1999 J. Hecht City of Light xi. 133 Maurer had tried to make lasers by doping glass with the rare earth europium. Compounds rare earth element n. any of a group of chemically similar metallic elements comprising the lanthanide series and also usually scandium and yttrium. ΚΠ 1888 Amer. Jrnl. Sci. 136 63 Passing to the rare earth elements, the ground under our feet is less secure. 1924 J. W. Mellor Comprehensive Treat. Inorg. & Theoret. Chem. V. xxxviii. 696 The four rare earth elements—dysprosium, Dy; holmium, Ho; erbium, Er; and thulium, Tm—are considered as a family or sub-group of the yttrium elements. 1958 Optima Mar. 22b/2 Thorium occurs chiefly in association with the rare-earth elements in monazite ore. 2000 Science 29 Sept. 2326/3 The separation of individual rare earth elements is a difficult process involving solvent extraction or ion exchange. rare earth metal n. = rare earth element n. ΚΠ 1877 Jrnl. Chem. Soc. 31 49 (heading) The quantivalence of the rare earth-metals. 1909 Jrnl. Industr. & Engin. Chem. 1 684/1 A process for obtaining chlorine..consisting in heating at a low temperature ammonium chloride with an oxide of a rare earth metal. 1959 Nomencl. Inorg. Chem. (I.U.P.A.C.) 6 The name rare-earth metals may be used for the elements Sc, Y, and La to Lu inclusive. 1996 Economist 31 Aug. 81/1 Mixed into the glass are small amounts of certain ‘rare-earth’ metals—praseodymium, erbium and thulium—in the form of their ions. This entry has been updated (OED Third Edition, December 2008; most recently modified version published online March 2022). < n.1863
随便看	sexual sexual assault sexual assault kit sexual athlete sexual athleticism sexual athletics sexual attraction sexual cell sexual character sexual characteristic sexual climax sexual dimorphism sexual discrimination sexual excitement sexual experience sexual harassment sexual intercourse sexual interference sexual inversion sexual invert sexual method sexual morality sexual objectification sexual offence sexual offender