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niobium

(Encyclopedia)niobium nīōˈbēəm [key], metallic chemical element; symbol Nb; at. no. 41; at. wt. 92.90638; m.p. about 2,468℃; b.p. 4,742℃; sp. gr. 8.57 at 20℃; valence +2, +3, +4, or +5. Niobium is a rare...

Nb

(Encyclopedia)Nb, symbol for the element niobium. ...

Cb

(Encyclopedia)Cb, formerly the symbol for the element columbium, now called niobium (Nb). ...

columbium

(Encyclopedia)columbium kəlŭmˈbēəm [key], symbol Cb, former name of the chemical element niobium. ...

tantalum

(Encyclopedia)tantalum tănˈtələm [key] [from Tantalus], metallic chemical element; symbol Ta; at. no. 73; at. wt. 180.94788; m.p. 2,996℃; b.p. 5,400±100℃; sp. gr. 16.65 at 20℃; valence +2, +3, +4, or +5....

Rose, Gustav

(Encyclopedia)Rose, Gustav go͝osˈtäf rōˈzə [key], 1798–1873, German mineralogist. He served as professor at the Univ. of Berlin from 1839. Noted especially as a crystallographer, he advanced the scientific ...

dubnium

(Encyclopedia)dubnium do͞obˈnēəm [key], artificially produced radioactive chemical element; symbol Db; at. no. 105; mass number of most stable isotope 268; m.p., b.p., and sp. gr. unknown; valence +5. Situated ...

vanadium

(Encyclopedia)vanadium vənāˈdēəm [key], metallic chemical element; symbol V; at. no. 23; at. wt. 50.9415; m.p. about 1,890℃; b.p. 3,380℃; sp. gr. about 6 at 20℃; valence +2, +3, +4, or +5. Vanadium is a ...

Elements (table)

(Encyclopedia)Elements 1 Parentheses indicate most stable isotope; brackets enclose lower and upper bounds of weight variation. ...

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