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{{Chembox
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| ImageFile = Nb2I10.svg
| ImageFile = Nb2I10.svg
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|Section1={{Chembox Identifiers
|Section1={{Chembox Identifiers
| CASNo = 13779-92-5
| CASNo = 13779-92-5
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 6YYE4L5XPW
| PubChem = 83728
| PubChem = 83728
| ChemSpiderID = 75550
| ChemSpiderID = 75550
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| GHSPictograms = {{GHS05}}
| GHSPictograms = {{GHS05}}
| GHSSignalWord = Danger
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|314|318}}
| HPhrases = {{H-phrases|314}}
| PPhrases = {{P-phrases|260|264|280|301+330+331|303+361+353|304+340|305+351+338|310|321|363|405|501}}
| PPhrases = {{P-phrases|260|264|280|301+330+331|303+361+353|304+340|305+351+338|310|321|363|405|501}}
| MainHazards =
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'''Niobium pentaiodide''' is the [[inorganic compound]] with the formula Nb<sub>2</sub>I<sub>10</sub>. It is a yellow, moisture-sensitive, diamagnetic solid. It forms upon heating metallic niobium with [[iodine]].<ref>G. Brauer "Hydrogen, Deuterium, Water" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 2. p. 1315.</ref> Its structure has been verified by single crystal [[X-ray diffraction]], which reveals an [[Octahedral molecular geometry#Bioctahedral molecular geometry|edge-shared bioctahedral structure]], as observed for many pentahalides of Nb and Ta. The bonds to the bridging iodides are 0.3 Å longer than the terminal Nb-I bonds.<ref>Krebs, Bernt; Sinram, Diethard "Darstellung, Struktur und Eigenschaften einer neuen Modifikation von NbI<sub>5</sub> (Preparation, structure and properties of a new modification of NbI<sub>5</sub>" Zeitschrift fǔr Naturforschung, Teil B: Anorganische Chemie, Organische Chemie 1980, volume 35b, pp. 12-16.</ref>
'''Niobium pentaiodide''' is the [[inorganic compound]] with the formula Nb<sub>2</sub>I<sub>10</sub>. Its name comes from the compound's [[empirical formula]], NbI<sub>5</sub>.<ref>Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford: Butterworth-Heinemann. {{ISBN|0-7506-3365-4}}.</ref> It is a diamagnetic, yellow solid that hydrolyses readily. The compound adopts an edge-shared bioctahedral structure, which means that two NbI<sub>5</sub> units are joined by a pair of [[bridging ligand|iodide bridges]]. There is no bond between the Nb centres.<ref>Krebs, Bernt; Sinram, Diethard "Darstellung, Struktur und Eigenschaften einer neuen Modifikation von NbI<sub>5</sub> (Preparation, structure and properties of a new modification of NbI<sub>5</sub>" Zeitschrift fǔr Naturforschung, Teil B: Anorganische Chemie, Organische Chemie 1980, volume 35b, pp. 12-16.</ref> [[Niobium(V) chloride]], [[niobium(V) bromide]], [[tantalum(V) chloride]], [[tantalum(V) bromide]], and [[tantalum(V) iodide]], all share this structural motif.

== Preparation ==
Niobium pentaiodide forms from the reaction of niobium with [[iodine]]:
:2 Nb + 5 I<sub>2</sub> → 2 NbI<sub>5</sub>
The method used for the preparation of tantalum(V) iodide using [[aluminium triiodide]] fails to produce pure pentaiodide.<ref name=brauer>{{cite book|author=G. Braurer|chapter=Niobium(V) Iodide|title=Handbook of Preparative Inorganic Chemistry, 2nd Ed. |editor=G. Brauer|publisher=Academic Press|year=1963|place=NY, NY|volume=1|pages=1315}}</ref>

== Properties ==
Niobium(V) iodide forms of dark, brassy, extremely moisture-sensitive needles or flakes. Its crystallises in the [[monoclinic crystal system]] with [[space group]] ''P''2<sub>1</sub>''/c'' (space group no. 14), a = 1058 pm, b = 658 pm, c = 1388 pm, β = 109.14°. The crystal structure consists of zigzag chains of corner-sharing NbI<sub>6</sub> octahedra. Since so far only twinned crystals of this phase have been obtained, and the structure determination is uncertain.<ref>{{Cite journal |last=Littke |first=W. |last2=Brauer |first2=G. |date=Oct 1963 |title=Darstellung und Kristallstruktur von Niobpentajodid |url=https://onlinelibrary.wiley.com/doi/10.1002/zaac.19633250304 |journal=Zeitschrift für anorganische und allgemeine Chemie |language=en |volume=325 |issue=3-4 |pages=122–129 |doi=10.1002/zaac.19633250304 |issn=0044-2313}}</ref> If the reaction of the elements is carried out with an excess of iodine, a [[triclinic]] modification is created with the space group P1 (No. 2), a = 759.1 pm, b = 1032.2 pm, c = 697.7 pm, α = 90 .93°, β = 116.17°, γ = 109.07°, which consists of isolated molecules Nb<sub>2</sub>I<sub>10</sub>.<ref name=brauer /><ref>B. Krebs, D. Sinram: ''Darstellung, Struktur und Eigenschaften einer neuen Modifikation von NbI<sub>5</sub>.'' In: ''Zeitschrift fuer Naturforschung, Teil B. Anorganische Chemie, Organische Chemie'', '''1980''', ''35'', S.&nbsp;12–16.</ref> This structure is isotypic with that of triclinic niobium(V) bromide.


==References==
==References==
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[[Category:Iodides]]
[[Category:Iodides]]
[[Category:Niobium compounds]]
[[Category:Niobium(V) compounds]]
[[Category:Metal halides]]
[[Category:Metal halides]]

Latest revision as of 11:38, 21 September 2023

Niobium pentaiodide
Names
Other names
Niobium(V) iodide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.034.006 Edit this at Wikidata
EC Number
  • 237-422-1
UNII
  • InChI=1S/5HI.Nb/h5*1H;/q;;;;;+5/p-5
    Key: FWIYBTVHGYLSAZ-UHFFFAOYSA-I
  • [Nb](I)(I)(I)(I)I
Properties
Nb2I10
Molar mass 1475
Appearance yellow solid
Density 5.30 g/cm3
Melting point 543 °C (1,009 °F; 816 K) sublimes
Hazards
GHS labelling:
GHS05: Corrosive
Danger
H314
P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Niobium pentaiodide is the inorganic compound with the formula Nb2I10. Its name comes from the compound's empirical formula, NbI5.[1] 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.[2] Niobium(V) chloride, niobium(V) bromide, tantalum(V) chloride, tantalum(V) bromide, and tantalum(V) iodide, all share this structural motif.

Preparation

[edit]

Niobium pentaiodide forms from the reaction of niobium with iodine:

2 Nb + 5 I2 → 2 NbI5

The method used for the preparation of tantalum(V) iodide using aluminium triiodide fails to produce pure pentaiodide.[3]

Properties

[edit]

Niobium(V) iodide forms of dark, brassy, extremely moisture-sensitive needles or flakes. Its crystallises in the monoclinic crystal system with space group P21/c (space group no. 14), a = 1058 pm, b = 658 pm, c = 1388 pm, β = 109.14°. The crystal structure consists of zigzag chains of corner-sharing NbI6 octahedra. Since so far only twinned crystals of this phase have been obtained, and the structure determination is uncertain.[4] If the reaction of the elements is carried out with an excess of iodine, a triclinic modification is created with the space group P1 (No. 2), a = 759.1 pm, b = 1032.2 pm, c = 697.7 pm, α = 90 .93°, β = 116.17°, γ = 109.07°, which consists of isolated molecules Nb2I10.[3][5] This structure is isotypic with that of triclinic niobium(V) bromide.

References

[edit]
  1. ^ Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford: Butterworth-Heinemann. ISBN 0-7506-3365-4.
  2. ^ Krebs, Bernt; Sinram, Diethard "Darstellung, Struktur und Eigenschaften einer neuen Modifikation von NbI5 (Preparation, structure and properties of a new modification of NbI5" Zeitschrift fǔr Naturforschung, Teil B: Anorganische Chemie, Organische Chemie 1980, volume 35b, pp. 12-16.
  3. ^ a b G. Braurer (1963). "Niobium(V) Iodide". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 1. NY, NY: Academic Press. p. 1315.
  4. ^ Littke, W.; Brauer, G. (Oct 1963). "Darstellung und Kristallstruktur von Niobpentajodid". Zeitschrift für anorganische und allgemeine Chemie. 325 (3–4): 122–129. doi:10.1002/zaac.19633250304. ISSN 0044-2313.
  5. ^ B. Krebs, D. Sinram: Darstellung, Struktur und Eigenschaften einer neuen Modifikation von NbI5. In: Zeitschrift fuer Naturforschung, Teil B. Anorganische Chemie, Organische Chemie, 1980, 35, S. 12–16.