Tantalum(IV) iodide

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Tantalum(IV) iodide
Identifiers
3D model (
JSmol
)
  • InChI=1S/4HI.Ta/h4*1H;/q;;;;+4/p-4
    Key: YGGDPBCUKJOEGM-UHFFFAOYSA-J
  • [I-].[I-].[I-].[I-].[Ta+4]
Properties
TaI4
Molar mass 688.57
Appearance black solid[1]
Melting point 398 °C (671 K) (decomposes)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Tantalum(IV) iodide is an inorganic compound with the chemical formula TaI4. It dissolves in water to give a green solution, but the color fades when left in the air and produces a white precipitate.[2]

Preparation

Tantalum(IV) iodide can be prepared by the reduction reaction of tantalum(V) iodide and tantalum.[2] If pyridine is used as the reducing agent, there is an adduct TaI4(py)2.[3]

Tantalum(IV) iodide can also be obtained by reacting tantalum(V) iodide with aluminum, magnesium or calcium at 380 °C. Ta6I14 is also formed. This makes it difficult to produce a very pure crystallized tantalum(IV) iodide.[4]

3 TaI5 + Al → 3 TaI4 + AlI3

Properties

Tantalum(IV) iodide is a black solid. It has a crystal structure isotypic to that of niobium(IV) iodide.[4] Single-crystalline tantalum(IV) iodide was first obtained in 2008 by Rafal Wiglusz and Gerd Meyer as a chance product of a reaction in a tantalum ampoule that was supposed to lead to the product Rb(Pr6C2)I12.[5] The single crystal has a triclinic crystal structure with space group P1 (space group no. 2) with two formula units per unit cell (a = 707.36 pm, b = 1064.64 pm, c = 1074.99 pm, α = 100.440°, β = 89.824° and γ = 104.392°). The crystal structure differs from that of other transition metal tetraiodides, which usually have a MI4/2I2/1 chain structure, as it consists of TaI6 octahedra bridged over a common surface to form a dimer. Two such dimers bridge over a common edge to form a tetramer.[6]

References

  1. ^ Georg Brauer: Handbuch der präparativen anorganischen Chemie. 3., umgearb. Auflage. Band III. Enke, Stuttgart 1981, ISBN 3-432-87823-0, pp. 1455.
  2. ^
    ISSN 0002-7863
    . Retrieved 2021-03-24.
  3. ISSN 0020-1669
    . Retrieved 2021-03-24.
  4. ^
    ISBN 978-3-432-87823-2
    .
  5. doi:10.1002/zaac.200700529
    .
  6. ^ Habermehl, Katja (2010). Neue Untersuchungen an Halogeniden des Niobs und Tantals (text.thesis.doctoral thesis). Universität zu Köln.
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