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Vanadium(III) oxide is the inorganic compound with the formula V 2 O 3.It is a black solid prepared by reduction of V 2 O 5 with hydrogen or carbon monoxide. [3] [4] It is a basic oxide dissolving in acids to give solutions of vanadium (III) complexes. [4]
Amphoteric is derived from the Greek word amphoteroi (ἀμφότεροι) meaning "both". Related words in acid-base chemistry are amphichromatic and amphichroic , both describing substances such as acid-base indicators which give one colour on reaction with an acid and another colour on reaction with a base.
Vanadium oxide mainly refers to: . Vanadium(II) oxide (vanadium monoxide), VO; Vanadium(III) oxide (vanadium sesquioxide or trioxide), V 2 O 3; Vanadium(IV) oxide (vanadium dioxide), VO 2
A vanadium ore or vanadium-rich residue is treated with sodium carbonate and an ammonium salt to produce sodium metavanadate, NaVO 3. This material is then acidified to pH 2–3 using H 2 SO 4 to yield a precipitate of "red cake" (see above). The red cake is then melted at 690 °C to produce the crude V 2 O 5.
An aqueous extract of this solid is acidified to produce "red cake", a polyvanadate salt, which is reduced with calcium metal. As an alternative for small-scale production, vanadium pentoxide is reduced with hydrogen or magnesium. Many other methods are also used, in all of which vanadium is produced as a byproduct of other processes. [71]
Vanadium(II) oxide is the inorganic compound with the idealized formula VO. It is one of the several binary vanadium oxides.It adopts a distorted NaCl structure and contains weak V−V metal to metal bonds.
Vanadium(IV) oxide or vanadium dioxide is an inorganic compound with the formula VO 2.It is a dark blue solid. Vanadium(IV) dioxide is amphoteric, dissolving in non-oxidising acids to give the blue vanadyl ion, [VO] 2+ and in alkali to give the brown [V 4 O 9] 2− ion, or at high pH [VO 4] 4−. [4]
Metalloids are metallic-looking, often brittle solids that are either semiconductors or exist in semiconducting forms, and have amphoteric or weakly acidic oxides. Typical elemental nonmetals have a dull, coloured or colourless appearance; are often brittle when solid; are poor conductors of heat and electricity; and have acidic oxides. Most or ...