NH4VO3

NH4VO3, commonly known as ammonium metavanadate, is an inorganic salt comprising the ammonium cation (NH4+) and the metavanadate anion (VO3−). In this compound, vanadium is in the +5 oxidation state. The solid is typically white to pale yellow and forms crystalline material that is soluble in water. Aqueous NH4VO3 solutions exhibit the characteristic yellow color associated with vanadium(V) species.

Preparation and structure

NH4VO3 can be prepared by combining sources of ammonium ions with metavanadate in solution and allowing crystallization to occur, or by reacting vanadium(V) oxide with ammonium-containing media to generate the metavanadate salt. In solution, the vanadate system exists in equilibrium among various polyvanadate species depending on pH, with VO3− being the basic unit in metavanadate salts.

Chemical properties

The compound is relatively stable under ambient conditions but decomposes upon strong heating, releasing ammonia and water and yielding vanadium pentoxide (V2O5). In aqueous solution, the vanadate species can interconvert with other VOx species as the pH changes, influencing color and reactivity.

Uses

NH4VO3 serves as a convenient source of vanadium(V) for laboratory synthesis and as a reagent in inorganic analytical chemistry. It is used to prepare vanadium-containing compounds and is involved in the production of vanadium oxide catalysts and related materials. It also appears in qualitative tests and in the preparation of coordination compounds involving vanadium.

Safety

Like other vanadium compounds, ammonium metavanadate can be irritant to skin, eyes, and the respiratory tract. Handle with appropriate personal protective equipment and dispose of according to local regulations for vanadium-containing materials.