 | |
| Identifiers | |
|---|---|
3D model (JSmol) | |
| |
| |
| 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 theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Tantalum(IV) iodide is an inorganic compound with the chemical formula TaI4. It dissolves inwater to give a green solution, but the color fades when left in the air and produces a white precipitate.[2]
Tantalum(IV) iodide can be prepared by the reduction reaction oftantalum(V) iodide andtantalum.[2] Ifpyridine is used as the reducing agent, there is anadduct 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]
Tantalum(IV) iodide is a black solid. It has a crystal structure isotypic to that ofniobium(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]
