Niobium(V) chloride

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Niobium(V) chloride
Niobium pentachloride solid.jpg
Niobium-pentachloride-dimer-2D.png
Names
IUPAC names
Niobium(V) chloride
Niobium pentachloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.042 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 233-059-8
PubChem CID
RTECS number
  • QU0350000
UNII
  • InChI=1S/5ClH.Nb/h5*1H;/q;;;;;+5/p-5
    Key: YHBDIEWMOMLKOO-UHFFFAOYSA-I
  • Cl[Nb](Cl)(Cl)(Cl)Cl
  • dimer:Cl[Nb-]1(Cl)(Cl)(Cl)[Cl+][Nb-]([Cl+]1)(Cl)(Cl)(Cl)Cl
Properties
NbCl5
Molar mass 270.17 g/mol
Appearanceyellow monoclinic crystals
deliquescent
Density 2.75 g/cm3
Melting point 204.7 °C (400.5 °F; 477.8 K)
Boiling point 248.2 °C (478.8 °F; 521.3 K)
decomposes
Solubility HCl, chloroform, CCl4
Thermochemistry
Std molar
entropy (S⦵298)
214.05 J K−1 mol−1
-797.47 kJ/mol
Hazards
GHS labelling:
GHS-pictogram-acid.svg GHS-pictogram-exclam.svg
Danger
H302, H312, H314, H332
P260, P261, P264, P270, P271, P280, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P363, P405, P501
Flash point Non-flammable
Related compounds
Other anions
Niobium(V) fluoride
Niobium(V) bromide
Niobium(V) iodide
Other cations
Vanadium(IV) chloride
Tantalum(V) chloride
Related niobium chlorides
 Niobium(III) chloride
Niobium(IV) 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(V) chloride, also known as niobium pentachloride, is a yellow crystalline solid. It hydrolyzes in air, and samples are often contaminated with small amounts of NbOCl3. It is often used as a precursor to other compounds of niobium. NbCl5 may be purified by sublimation. [1]

Contents

Structure and properties

Ball-and-stick model of niobium pentachloride Niobium-pentachloride-from-xtal-3D-balls.png
Ball-and-stick model of niobium pentachloride

Niobium(V) chloride forms chloro-bridged dimers in the solid state (see figure). Each niobium centre is six-coordinate, but the octahedral coordination is significantly distorted. The equatorial niobium–chlorine bond lengths are 225 pm (terminal) and 256 pm (bridging), whilst the axial niobium-chlorine bonds are 229.2 pm and are deflected inwards to form an angle of 83.7° with the equatorial plane of the molecule. The Nb–Cl–Nb angle at the bridge is 101.3°. The Nb–Nb distance is 398.8 pm, too long for any metal-metal interaction. [2] NbBr5, NbI5, TaCl5 TaBr5 and TaI5 are isostructural with NbCl5.

Preparation

Niobium pentachloride liquid and vapor. Niobium pentachloride2.jpg
Niobium pentachloride liquid and vapor.

Industrially, niobium pentachloride is obtained by direct chlorination of niobium metal at 300 to 350 °C: [3]

2 Nb + 5 Cl2 → 2 NbCl5

In the laboratory, niobium pentachloride is often prepared from Nb2O5, the main challenge being incomplete reaction to give NbOCl3. The conversion can be effected with thionyl chloride: [4] It also can be prepared by chlorination of niobium pentoxide in the presence of carbon at 300 °C.

Uses

Niobium(V) chloride is the main precursor to the alkoxides of niobium, which find uses in sol-gel processing. It is also the precursor to many other Nb-containing reagents, including most organoniobium compounds.

In organic synthesis, NbCl5 is a very specialized Lewis acid in activating alkenes for the carbonyl-ene reaction and the Diels-Alder reaction. Niobium chloride can also generate N-acyliminium compounds from certain pyrrolidines which are substrates for nucleophiles such as allyltrimethylsilane, indole, or the silyl enol ether of benzophenone. [5]

Related Research Articles

<span class="mw-page-title-main">Phosphorus pentachloride</span> Chemical compound

Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides/oxychlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive solid, although commercial samples can be yellowish and contaminated with hydrogen chloride.

Pelopium was the proposed name for a new element found by the chemist Heinrich Rose in 1845. The name derived from the Greek king and later god Pelops, son of Tantalus. During the analysis of the mineral tantalite, he concluded that it does contain an element similar to niobium and tantalum. The similar reactivity of niobium and tantalum complicated preparation of pure samples and therefore several new elements were proposed, which were later found to be mixtures of niobium and tantalum.

<span class="mw-page-title-main">Tantalum(V) chloride</span> Chemical compound

Tantalum(V) chloride, also known as tantalum pentachloride, is an inorganic compound with the formula TaCl5. It takes the form of a white powder and is commonly used as a starting material in tantalum chemistry. It readily hydrolyzes to form tantalum(V) oxychloride (TaOCl3) and eventually tantalum pentoxide (Ta2O5); this requires that it be synthesised and manipulated under anhydrous conditions, using air-free techniques.

<span class="mw-page-title-main">Antimony pentachloride</span> Chemical compound

Antimony pentachloride is a chemical compound with the formula SbCl5. It is a colourless oil, but typical samples are yellowish due to dissolved chlorine. Owing to its tendency to hydrolyse to hydrochloric acid, SbCl5 is a highly corrosive substance and must be stored in glass or PTFE containers.

<span class="mw-page-title-main">Molybdenum(V) chloride</span> Chemical compound

Molybdenum(V) chloride is the inorganic compound with the empirical formula MoCl5. This dark volatile solid is used in research to prepare other molybdenum compounds. It is moisture-sensitive and soluble in chlorinated solvents.

<span class="mw-page-title-main">Platinum(II) chloride</span> Chemical compound

Platinum(II) chloride is the chemical compound PtCl2. It is an important precursor used in the preparation of other platinum compounds. It exists in two crystalline forms, but the main properties are somewhat similar: dark brown, insoluble in water, diamagnetic, and odorless.

<span class="mw-page-title-main">Tantalum(V) bromide</span> Chemical compound

Tantalum(V) bromide is the inorganic compound with the formula Ta2Br10. Its name comes from the compound's empirical formula, TaBr5. It is a diamagnetic, orange solid that hydrolyses readily. The compound adopts an edge-shared bioctahedral structure, which means that two TaBr5 units are joined by a pair of bromide bridges. There is no bond between the Ta centres. Niobium(V) chloride, niobium(V) bromide, niobium(V) iodide, tantalum(V) chloride, and tantalum(V) iodide all share this structural motif.

<span class="mw-page-title-main">Nitrosyl chloride</span> Chemical compound

Nitrosyl chloride is the chemical compound with the formula NOCl. It is a yellow gas that is commonly encountered as a component of aqua regia, a mixture of 3 parts concentrated hydrochloric acid and 1 part of concentrated nitric acid. It is a strong electrophile and oxidizing agent. It is sometimes called Tilden's reagent, after William A. Tilden, who was the first to produce it as a pure compound.

Niobocene dichloride is the organometallic compound with the formula (C5H5)2NbCl2, abbreviated Cp2NbCl2. This paramagnetic brown solid is a starting reagent for the synthesis of other organoniobium compounds. The compound adopts a pseudotetrahedral structure with two cyclopentadienyl and two chloride substituents attached to the metal. A variety of similar compounds are known, including Cp2TiCl2.

<span class="mw-page-title-main">Trirhenium nonachloride</span> Chemical compound

Trirhenium nonachloride is a compound with the formula ReCl3, sometimes also written Re3Cl9. It is a dark red hygroscopic solid that is insoluble in ordinary solvents. The compound is important in the history of inorganic chemistry as an early example of a cluster compound with metal-metal bonds. It is used as a starting material for synthesis of other rhenium complexes.

<span class="mw-page-title-main">Rhenium pentachloride</span> Chemical compound

Rhenium pentachloride is an inorganic compound of chlorine and rhenium. The compound has the formula Re2Cl10 but it is usually referred to as rhenium pentachloride. It is a red-brown solid.

<span class="mw-page-title-main">Niobium pentoxide</span> Chemical compound

Niobium pentoxide is the inorganic compound with the formula Nb2O5. A colorless, insoluble, and fairly unreactive solid, it is the most widespread precursor for other compounds and materials containing niobium. It is predominantly used in alloying, with other specialized applications in capacitors, optical glasses, and the production of lithium niobate.

<span class="mw-page-title-main">Arsenic pentachloride</span> Chemical compound

Arsenic pentachloride is a chemical compound of arsenic and chlorine. This compound was first prepared in 1976 through the UV irradiation of arsenic trichloride, AsCl3, in liquid chlorine at −105 °C. AsCl5 decomposes at around −50 °C. The structure of the solid was finally determined in 2001. AsCl5 is similar to phosphorus pentachloride, PCl5 in having a trigonal bipyramidal structure where the equatorial bonds are shorter than the axial bonds (As-Cleq = 210.6 pm, 211.9 pm; As-Clax= 220.7 pm).

<span class="mw-page-title-main">Molybdenum tetrachloride</span> Chemical compound

Molybdenum tetrachloride is the inorganic compound with the empirical formula MoCl4. The material exists as two polymorphs, both being dark-colored paramagnetic solids. These compounds are mainly of interest as precursors to other molybdenum complexes.

<span class="mw-page-title-main">Niobium(IV) chloride</span> Chemical compound

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.

<span class="mw-page-title-main">Niobium oxychloride</span> Chemical compound

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.

<span class="mw-page-title-main">Niobium pentaiodide</span> Chemical compound

Niobium pentaiodide is the inorganic compound with the formula Nb2I10. Its name comes from the compound's empirical formula, NbI5. It is a diamagnetic, yellow solid that hydrolyses readily. The compound adopts an edge-shared bioctahedral structure, which means that two NbI5 units are joined by a pair of iodide bridges. There is no bond between the Nb centres. Niobium(V) chloride, niobium(V) bromide, tantalum(V) chloride, tantalum(V) bromide, and tantalum(V) iodide, all share this structural motif.

<span class="mw-page-title-main">Organotantalum chemistry</span> Chemistry of compounds containing a carbon-to-tantalum bond

Organotantalum chemistry is the chemistry of chemical compounds containing a carbon-to-tantalum chemical bond. A wide variety of compound have been reported, initially with cyclopentadienyl and CO ligands. Oxidation states vary from Ta(V) to Ta(-I).

<span class="mw-page-title-main">Trithiazyl trichloride</span> Chemical compound

Trithiazyl trichloride is the inorganic compound with the formula (NSCl)3. A white solid, it is a precursor to other sulfur nitrides, but has no commercial applications.

Niobium(III) chloride also known as niobium trichloride is a compound of niobium and chlorine. The binary phase NbCl3 is not well characterized but many adducts are known.

References

  1. ↑ Cotton, F. Albert; Wilkinson, Geoffrey (1980), Advanced Inorganic Chemistry (4th ed.), New York: Wiley, ISBN   0-471-02775-8
  2. ↑ Cotton, F.A., P. A. Kibala, M. Matusz and R. B. W. Sandor (1991). "Structure of the Second Polymorph of Niobium Pentachloride". Acta Crystallogr. C . 47 (11): 2435–2437. doi:10.1107/S0108270191000239.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. ↑ Joachim Eckert; Hermann C. Starck (2005). "Niobium and Niobium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a17_251. ISBN   3-527-30673-0.
  4. ↑ Brown, D. (1957). "Niobium(V) Chloride and Hexachloroniobates(V)". Inorganic Syntheses. Vol. 9. pp. 88–92. doi:10.1002/9780470132401.ch24. ISBN   978-0-470-13240-1.
  5. ↑ Andrade, C. K. Z.; Rocha, R. O.; Russowsky, D. & Godoy, M. N. (2005). "Studies on the Niobium Pentachloride-Mediated Nucleophilic Additions to an Enantiopure Cyclic N-acyliminium Ion Derived from (S)-malic acid". J. Braz. Chem. Soc. 16 (3b): 535–539. doi: 10.1590/S0103-50532005000400007 . hdl: 10183/24558 .
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