Molybdic

Molybdic is an adjective relating to molybdenum and its compounds, especially those in the +6 oxidation state. It is used in reference to molybdate ions (such as MoO4^2−) and to molybdic acids, notably molybdic acid, H2MoO4.

Chemically, molybdic acid forms when molybdenum trioxide (MoO3) dissolves in water. In solution it can lose protons to form HMoO4^− and MoO4^2−, with the acid–base behavior depending on pH. These species are central to the chemistry of molybdenates and to polyoxometalate chemistry, where condensed molybdenum-oxide clusters arise from hydrated forms of molybdate.

Common forms of molybdic materials include MoO3 as an oxide and salts such as ammonium molybdate ((NH4)6Mo7O24·4H2O) and sodium molybdate Na2MoO4. These reagents serve as sources of molybdenum in chemical synthesis, as analytical standards, and as precursors to more complex molybdate- or polyoxometalate systems. In catalysis and materials science, molybdate-derived species and polyoxometalates derived from molybdic acids are studied for oxidation and acid-catalysis applications.

Applications and relevance often center on analytical chemistry and inorganic synthesis. In phosphate determination, molybdate reagents form a yellow complex that can be measured colorimetrically (and, after reduction, as molybdenum blue). In research and industry, molybdate- and molybdenic-acid derivatives underpin various catalytic and material-science applications, including the preparation of heteropoly and isopoly molybdenum oxides.

See also: Molybdenum, Molybdate, Phosphomolybdic acid.