Niobium(IV) chloride
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IUPAC name
Niobium(IV) chloride
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Other names
Niobium tetrachloride
Niobium chloride | |
Identifiers | |
PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
NbCl4 | |
Molar mass | 234.718 g/mol |
Appearance | Violet-Black Crystals |
Density | 3.2 g/cm3 |
Melting point | Dec. 800 °C |
Boiling point | Subl. 275 °C/10−4 mmHg |
Reacts | |
Related compounds | |
Other anions
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Niobium(IV) bromide Niobium(IV) iodide |
Other cations
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Vanadium(IV) chloride
Tantalum(IV) chloride |
Related niobium chlorides [1]
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Niobium(III) chloride Niobium(V) chloride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Niobium(IV) chloride, also known as niobium tetrachloride, is the chemical compound of formula NbCl4. This compound exists as dark violet crystals, is highly sensitive to air and moisture, and disproportiates into niobium(III) chloride and niobium(V) chloride when heated.[2]
Structure and properties
In the solid state, niobium(IV) chloride exists as chains of edge-sharing octahedra with alternating Nb-Nb distances of lengths 302.9 and 379.4 pm. The shorter distances correspond to Nb-Nb bonds, which result in the compound's diamagnetism. Its structure is very similar to that of tungsten(IV) chloride.
Other
Niobium chloride rapidly oxidizes and hydrolyzes in air to form
Preparation
Niobium(IV) chloride is typically produced by allowing elemental niobium and niobium(V) chloride crystals to react over several days in a temperature gradient, with the metal around 400 °C and the salt around 250 °C.[4]
- 4 NbCl5 + Nb → 5 NbCl4
Niobium (IV) chloride can also prepared by a similar reduction of
- 3 NbCl5 + Al → 3 NbCl4 + AlCl3
A similar technique is also used in the synthesis of
At 400 °C NbCl4 disproportiates:
- 2 NbCl4 → NbCl3 + NbCl5
Reactions
The disproportiation of niobium(IV) chloride can be used to make tetrachlorobis(tetrahydrofuran) niobium, a useful
- 3 NbCl5 + Al + 3 CH3CN → 3 NbCl4(NCCH3)3 + AlCl3
- 3 NbCl4(NCCH3)3 + AlCl3 + 3 C4H8O → 3 NbCl4(thf)2 + 9 MeCN + AlCl3(thf)
References
- ^ CRC, Handbook of Chemistry and Physics, 89th Ed., 2008/09, editor D. Lide, Cleveland, OH: CRC Press, p. 4-36.
- ^ Macintyre, J.E.; Daniel, F.M.; Chapman and Hall; Stirling, V.M. Dictionary of Inorganic Compounds. 1992, Cleveland, OH: CRC Press, p. 2957
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- ^ Hubert-Pfalzgraf, L.G. Niobium & Tantalum: Inorganic & Coordination Chemistry. 2006: John Wiley & Sons, Ltd.
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