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
PubChem CID	139509 has wrong formula
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

References

1. Ströbele, Markus; Meyer, Hans-Jürgen (2002). "Neubestimmung der Kristallstruktur von NbOCl₃". Zeitschrift für anorganische und allgemeine Chemie. 628 (2): 488–491. doi:10.1002/1521-3749(200202)628:2<488::AID-ZAAC488>3.0.CO;2-B.
2. Beck, Johannes; Bordinhão, Jairo (2005). "Polar [NbOCl₃]_2n and [NbOX⁻
   ₄]_n (X = Cl, Br) Chains in the Structures of NbOCl₃ and the Thallium-Halogenooxoniobates Tl[NbOCl₄] and Tl[NbOBr₄] — Synthesis, Crystal Structures and Optical Second Harmonic Generation". Zeitschrift für anorganische und allgemeine Chemie. 631 (6–7): 1261–1266. doi:10.1002/zaac.200500041.
3. Greenwood, N. N. (January 1, 1970). "Chapter 5: Vibrational Spectra". Spectroscopic Properties of Inorganic and Organometallic Compounds. Royal Society of Chemistry. p. 196. ISBN 9780851860237.
4. G. Brauer (1963). "Niobium Oxytrichloride". In Brauer, G. (ed.). Handbook of Preparative Inorganic Chemistry. Vol. 2 (2nd ed.). New York: Academic Press. p. 1307.
5. Jena, P. K.; Brocchi, E. A.; Garcia, R. I. (1997). "Kinetics of chlorination of niobium pentoxide by carbon tetrachloride". Metallurgical and Materials Transactions B. 28 (1): 39–45. Bibcode:1997MMTB...28...39J. doi:10.1007/s11663-997-0125-0. S2CID 98226151..