Niobium dioxide, is the chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 with the formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 NbO₂. It is a bluish black non-stoichiometric solid with a composition range of NbO_1.94-NbO_2.09 It can be prepared by reacting Nb₂O₅ with H₂ at 800-1350 °C. An alternative method is reaction of Nb₂O₅ with Nb powder at 1100 °C.

The room temperature form NbO₂ has a tetragonal, rutile

Titanium dioxide

Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of...

-like structure with short Nb-Nb distances indicating Nb-Nb bonding. High temp form also has a rutile

Titanium dioxide

Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of...

-like structure with short Nb-Nb distances.
Two high pressure phases have been reported one with a rutile

Titanium dioxide

Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of...

-like structure, again with short Nb-Nb distances, and a higher pressure with baddeleyite

Baddeleyite

Baddeleyite is a rare zirconium oxide mineral , occurring in a variety of monoclinic prismatic crystal forms. It is transparent to translucent, has high indices of refraction, and ranges from colorless to yellow, green, and dark brown. Baddeleyite is a refractory mineral, with a melting point of...

-related structure.

NbO₂ is insoluble in water and is a powerful reducing agent, reducing carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 to carbon and sulfur dioxide

Sulfur dioxide

Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...

 to sulfur. In an industrial process for the production of niobium metalhttp://www.research.bayer.com/edition_16/16_New_capacitors.pdfx, NbO₂ is produced as an intermediate, by the hydrogen reduction of Nb₂O₅

Niobium pentoxide

Niobium pentoxide is the inorganic compound with the formula Nb2O5. It is a colourless insoluble solid that is fairly unreactive. It is the main precursor to all materials made of niobium, the dominant application being alloys, but other specialized applications include capacitors, lithium niobate,...

. The NbO₂ is subsequently reacted with magnesium vapour to produce niobium metal.