Thin films of NbO2, with thicknesses ranging from 1000 to 20 000 Å, were prepared by r.f. sputtering powder targets of NbO2 in a reducing atmosphere of 90vol.%Ar–10vol.%H. 

http://www.sciencedirect.com/science/article/pii/0040609082906228

 Pure NbO2 supplier:

http://noahtech.com/products/18280

 The Niobium oxide (NbO2) must be stored in airtight containers and placed in a dry, cool, ventilated place at room temperature. It should avoid contact with light, ignition source, high temperature. Niobium oxide (NbO2) is a powerful reducing agent, reducing carbon dioxide to carbon and sulfur dioxide to sulfur.

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