Nb2O5

Niobium(V) oxide, with the chemical formula Nb2O5, is the oxide of niobium in the +5 oxidation state. It is a solid that generally appears pale yellow to white and is insoluble in water. Nb2O5 is a wide-bandgap semiconductor, with a typical bandgap in the range of about 3.2 to 3.4 eV, and it shows catalytic and optical properties that reflect its chemical stability and electronic structure.

The material exists in several crystalline polymorphs, the most common forms being orthorhombic and monoclinic. The stability of these forms depends on temperature and synthesis conditions. Nb2O5 is known for high thermal stability and chemical resistance, making it useful as a catalyst support and as a functional component in coatings and electronic materials. It also has a relatively high refractive index among metal oxides, which contributes to its utility in optical coatings.

Industrial preparation typically involves the calcination or oxidation of niobium-containing precursors, such as hydrated niobium oxides or niobium oxychloride, in air to yield Nb2O5. The oxide is used in various applications, including as a catalyst support for acid-catalyzed reactions and as an active component in catalysts for selective oxidation. It serves as a high-k dielectric material in electronic devices and has been studied as an electrochromic material for certain smart-window applications. Nb2O5 is also explored as an electrode material in lithium-ion batteries due to its stability and rate performance.

In nature, Nb2O5 is not commonly found as a stand-alone mineral but is produced industrially from niobium-containing ores such as columbite-tantalite. Safety considerations include its irritant nature in powder form, with standard handling precautions recommended.