Niobium oxychloride

Niobium oxychloride is the inorganic compound with the formula NbOCl₃. 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.

Niobium oxychloride

Names
IUPAC name Niobium (V) Oxychloride
Other names Niobium oxytrichloride
Identifiers
CAS Number	13597-20-1 Y
3D model (JSmol)	Interactive image
InChI InChI=1S/3ClH.Nb.O/h3*1H;;/q;;;+3;/p-3 Key: SEEQRJAHRTUYAE-UHFFFAOYSA-K
SMILES O=[Nb](Cl)(Cl)Cl
Properties
Chemical formula	Cl3NbO
Molar mass	215.26 g·mol−1
Appearance	white crystals
Melting point	sublimes above 200 °C
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Structure

In the solid state the coordination sphere for niobium is a distorted octahedron. The Nb–O bonds and Nb–Cl bonds are unequal. This structure can be described as planar Nb₂Cl₆ core connected by O–Nb–O bridges. In this way, the compound is best described as a polymer, consisting of a double stranded chain.^[1][2]

In the gas phase above 320 °C the Raman spectrum is consistent with a pyramidal monomer containing a niobium–oxygen double bond.^[3]

Gaseous NbOCl₃ is a tetrahedral molecule.

Synthesis

Niobium oxychloride is prepared by treating the pentachloride with oxygen:^[4]

NbCl₅ + ⁠1/2⁠ O₂ → NbOCl₃ + Cl₂

This reaction is conducted at about 200 °C. NbOCl₃ also forms as a major side-product in the reaction of niobium pentoxide with various chlorinating agents such as carbon tetrachloride and thionyl chloride.^[4][5]

2 Nb₂O₅ + 6 CCl₄ → 4 NbOCl₃ + 6 COCl₂