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单词 columbite
释义

columbite


co·lum·bite

C0495500 (kə-lŭm′bīt′)n. A black, red-brown, or colorless mineral, essentially (Fe, Mn)(Nb, Ta)2O6, the principal ore of niobium.
[columb(ium) + -ite.]

columbite

(kəˈlʌmbaɪt) n (Minerals) a black mineral consisting of a niobium oxide of iron and manganese in orthorhombic crystalline form: occurs in coarse granite, often with tantalite, and is an ore of niobium. Formula: (Fe, Mn)(Nb)2O6. Also called: niobite [C19: from columbium + -ite1]

co•lum•bite

(kəˈlʌm baɪt)

n. a black mineral, mainly iron niobate, (Fe, Mn)Nb2O6, the chief ore of niobium. [1795–1805]
Thesaurus
Noun1.columbite - a black mineral that is an ore of niobium and tantalumniobiteatomic number 41, Nb, niobium - a soft grey ductile metallic element used in alloys; occurs in niobite; formerly called columbiumatomic number 73, Ta, tantalum - a hard grey lustrous metallic element that is highly resistant to corrosion; occurs in niobite and fergusonite and tantalitemineral - solid homogeneous inorganic substances occurring in nature having a definite chemical composition

Columbite


columbite

[kə′ləm‚bīt] (mineralogy) (Fe,Mn)(Cb,Ta)2O6 An iron-black mineral with a submetallic luster that crystallizes in the orthorhombic system; the chief ore mineral of niobium (columbium); hardness is 6 on Mohs scale, and specific gravity is 5.4-6.5. Also known as dianite; greenlandite; niobite.

Columbite

 

(from Latin columbium, an alternate name for niobium), a mineral of the columbite-tantalite group, combining complex oxides of the AB2O6 type and forming the isomorphic series FeNb2O6—MnNb2O6 (columbite proper) and FeTa2O6—MnTa2O6 (tantalite). The columbites also include members of isomorphic series in which niobium (in weight percent) predominates over tantalum.

The varieties of columbite include tantalocolumbite (20–40 percent Ta2O5), ferrocolumbite (FeO : MnO > 3 : 1), manganocolumbite (MnO : FeO > 3:1), magnesiocolumbite (FeO < MgO > MnO), and ixiolite (to 13 percent SnO2). In addition to the basic components, columbite almost always contains admixtures of titanium, tungsten, rare earth elements, uranium, thorium, and zirconium. Columbite crystallizes in the rhombic system. Its structure is based on the closest possible hexagonal (double-layered) packing of oxygen atoms, in the alternating layers of which the octahedral spaces are occupied in turn by (Nb, Ta) and (Fe, Mn). Columbite crystals are short prismatic, thin tabular, or tabular. They are black, brownish black, or, less often, reddish brown (manganocolumbites). The hardness of columbite is 6.0 on the mineralogical scale; the density, 5,150–6,350 kg per cu m (tantalocolumbites). Genetically, columbite is related to the quartz-bearing subalkaline syenites and the acidic alaskites, biotites, and binary granites, and particularly, to their pegmatitic and postmagmatic pneumatolytic and hydrothermal derivatives. Columbite is a source of niobium.

columbite


  • noun

Synonyms for columbite

noun a black mineral that is an ore of niobium and tantalum

Synonyms

  • niobite

Related Words

  • atomic number 41
  • Nb
  • niobium
  • atomic number 73
  • Ta
  • tantalum
  • mineral
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