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.
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| Names | |
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| IUPAC name
Niobium (V) Oxychloride
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| Other names
Niobium oxytrichloride
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| Identifiers | |
3D model (JSmol)
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PubChem CID
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| Properties | |
| 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).
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Structure
editIn 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]
Synthesis
editNiobium 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
edit- ^ 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.
- ^ 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. - ^ 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.
- ^ a b G. Brauer (1963). "Niobium Oxytrichloride". In Brauer, G. (ed.). Handbook of Preparative Inorganic Chemistry. Vol. 2 (2nd ed.). New York: Academic Press. p. 1307.
- ^ 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..