Niobium oxychloride is the inorganic compound with the formula NbOCl<sub>3</sub>. It is a white, crystalline, diamagnetic solid. It is often found as an impurity in samples of niobium pentachloride, a common reagent in niobium chemistry.
In the solid state the coordination sphere for niobium is a distorted octahedron. The NbâÂÂO bonds and NbâÂÂCl bonds are unequal. This structure can be described as planar Nb<sub>2</sub>Cl<sub>6</sub> core connected by OâÂÂNbâÂÂO bridges. In this way, the compound is best described as a polymer, consisting of a double stranded chain.
In the gas phase above 320 ðC the Raman spectrum is consistent with a pyramidal monomer containing a niobiumâÂÂoxygen double bond.
Niobium oxychloride is prepared by treating the pentachloride with oxygen:
This reaction is conducted at about 200 ðC. NbOCl<sub>3</sub> also forms as a major side-product in the reaction of niobium pentoxide with various chlorinating agents such as carbon tetrachloride and thionyl chloride.