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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 ...

organic chemistry

(Encyclopedia)organic chemistry, branch of chemistry dealing with the compounds of carbon. While it is only the fourteenth most common element on earth, carbon forms by far the greatest number of different compound...

gadolinium

(Encyclopedia)gadolinium gădəlĭnˈēəm [key], metallic chemical element; symbol Gd; at. no. 64; at. wt. 157.25; m.p. 1,312℃; b.p. 3,233℃; sp. gr. 7.898 at 25℃; valence +3. Gadolinium is a malleable, ducti...

gallium

(Encyclopedia)gallium gălˈēəm [key], metallic chemical element; symbol Ga; at. no. 31; at. wt. 69.723; m.p. 29.78℃; b.p. 2,403℃; sp. gr. 5.904 at 29.6℃ (solid), 6.095 at 29.8℃ (liquid); valence +2 or +3...

guanine

(Encyclopedia)guanine gwäˈnēn [key], organic base of the purine family. It was reported (1846) to be in the guano of birds; later (1879–84) it was established as one of the major constituents of nucleic acids....

gum, colloidal plant substance

(Encyclopedia)gum, term commonly applied to any of a wide variety of colloidal substances somewhat similar in appearance and general characteristics, exuded by or extracted from plants. In this classification, howe...

cerium

(Encyclopedia)cerium sērˈēəm [key] [from the asteroid Ceres], metallic chemical element; symbol Ce; at. no. 58; at. wt. 140.116; m.p. 799℃; b.p. 3,426℃; sp. gr. 6.77 at 25℃; valence +3 or +4. Cerium is a ...

Andaman and Nicobar Islands

(Encyclopedia)Andaman and Nicobar Islands ănˈdəmən, nĭkˈōbär [key], union territory (2001 provisional pop. 356,265), India, in the Bay of Bengal. Port Blair, in the Andamans, is...

amino group

(Encyclopedia)amino group, in chemistry, functional group that consists of a nitrogen atom attached by single bonds to hydrogen atoms, alkyl groups, aryl groups, or a combination of these three. An organic compound...

weather balloon

(Encyclopedia)weather balloon, balloon used in the measurement and evaluation of mostly upper atmospheric conditions (see atmosphere). Information may be gathered during the vertical ascent of the balloon through t...