Hafnium(IV) iodide

Last updated
Hafnium(IV) iodide
HfI4.tif
Names
IUPAC name
Hafnium(IV) iodide
Other names
hafnium tetraiodide, tetraiodohafnium
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.150.349 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 621-502-1
PubChem CID
  • InChI=1S/Hf.4HI/h;4*1H/q+4;;;;/p-4
    Key: YCJQNNVSZNFWAH-UHFFFAOYSA-J
  • I[Hf](I)(I)I
Properties
HfI4
Molar mass 686.11 [1]
Appearancered-orange [1]
Density 5.60 g/cm3 [1]
Melting point 449 °C (840 °F; 722 K) [1]
Boiling point 394 °C (741 °F; 667 K) [1] (sublimes)
Structure
Monoclinic, mS40
C2/c, No. 15 [2]
a = 1.1787 nm, b = 1.1801 nm, c = 1.2905 nm
Related compounds
Other anions
Hafnium(IV) fluoride
Hafnium(IV) chloride
Hafnium(IV) bromide
Other cations
Titanium(IV) iodide
Zirconium(IV) iodide
Related compounds
Hafnium(III) iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Hafnium(IV) iodide is the inorganic compound with the formula HfI4. It is a red-orange, moisture sensitive, sublimable solid that is produced by heating a mixture of hafnium with excess iodine. [2] It is an intermediate in the crystal bar process for producing hafnium metal.

In this compound, the hafnium centers adopt octahedral coordination geometry. Like most binary metal halides, the compound is a polymeric. It is one-dimensional polymer consisting of chains of edge-shared bioctahedral Hf2I8 subunits, similar to the motif adopted by HfCl4. The nonbridging iodide ligands have shorter bonds to Hf than the bridging iodide ligands. [2]

Related Research Articles

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Hafnium is a chemical element; it has symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1923, by Dirk Coster and George de Hevesy, making it the penultimate stable element to be discovered. Hafnium is named after Hafnia, the Latin name for Copenhagen, where it was discovered.

<span class="mw-page-title-main">Zirconium</span> Chemical element, symbol Zr and atomic number 40

Zirconium is a chemical element; it has symbol Zr and atomic number 40. The name zirconium is derived from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian zargun. It is a lustrous, grey-white, strong transition metal that closely resembles hafnium and, to a lesser extent, titanium. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Zirconium forms a variety of inorganic and organometallic compounds such as zirconium dioxide and zirconocene dichloride, respectively. Five isotopes occur naturally, four of which are stable. Zirconium compounds have no known biological role.

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<span class="mw-page-title-main">Van Arkel–de Boer process</span> Process for the commercial production of pure titanium and zirconium

The van Arkel–de Boer process, also known as the iodide process or crystal-bar process, was the first industrial process for the commercial production of pure ductile titanium, zirconium and some other metals. It was developed by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925. Now it is used in the production of small quantities of ultrapure titanium and zirconium. It primarily involves the formation of the metal iodides and their subsequent decomposition to yield pure metal.

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

Hafnium(IV) chloride is the inorganic compound with the formula HfCl4. This colourless solid is the precursor to most hafnium organometallic compounds. It has a variety of highly specialized applications, mainly in materials science and as a catalyst.

<span class="mw-page-title-main">Copper(I) iodide</span> Chemical compound

Copper(I) iodide is the inorganic compound with the formula CuI. It is also known as cuprous iodide. It is useful in a variety of applications ranging from organic synthesis to cloud seeding.

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

Zirconium(IV) chloride, also known as zirconium tetrachloride, is an inorganic compound frequently used as a precursor to other compounds of zirconium. This white high-melting solid hydrolyzes rapidly in humid air.

<span class="mw-page-title-main">Titanium tetraiodide</span> Chemical compound

Titanium tetraiodide is an inorganic compound with the formula TiI4. It is a black volatile solid, first reported by Rudolph Weber in 1863. It is an intermediate in the van Arkel–de Boer process for the purification of titanium.

Zirconium(IV) bromide is the inorganic compound with the formula ZrBr4. This colourless solid is the principal precursor to other Zr–Br compounds.

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

Zirconium(IV) iodide is the chemical compound with the formula ZrI4. It is the most readily available iodide of zirconium. It is an orange-coloured solid that degrades in the presence of water. The compound was once prominent as an intermediate in the purification of zirconium metal.

<span class="mw-page-title-main">Hafnium carbide</span> Chemical compound

Hafnium carbide (HfC) is a chemical compound of hafnium and carbon. Previously the material was estimated to have a melting point of about 3,900 °C. More recent tests have been able to conclusively prove that the substance has an even higher melting point of 3,958 °C exceeding those of tantalum carbide and tantalum hafnium carbide which were both previously estimated to be higher. However, it has a low oxidation resistance, with the oxidation starting at temperatures as low as 430 °C. Experimental testing in 2018 confirmed the higher melting point yielding a result of 3,982 (±30°C) with a small possibility that the melting point may even exceed 4,000°C.

<span class="mw-page-title-main">Thallium(I) iodide</span> Chemical compound

Thallium(I) iodide is a chemical compound with the formula TlI. It is unusual in being one of the few water-insoluble metal iodides, along with AgI, CuI, SnI2, SnI4, PbI2 and HgI2.

Vanadium(IV) fluoride (VF4) is an inorganic compound of vanadium and fluorine. It is paramagnetic yellow-brown solid that is very hygroscopic. Unlike the corresponding vanadium tetrachloride, the tetrafluoride is not volatile because it adopts a polymeric structure. It decomposes before melting.

<span class="mw-page-title-main">Hafnium tetrafluoride</span> Chemical compound

Hafnium tetrafluoride is the inorganic compound with the formula HfF4. It is a white solid. It adopts the same structure as zirconium tetrafluoride, with 8-coordinate Hf(IV) centers.

<span class="mw-page-title-main">Hafnium disulfide</span> Chemical compound

Hafnium disulfide is an inorganic compound of hafnium and sulfur. It is a layered dichalcogenide with the chemical formula is HfS2. A few atomic layers of this material can be exfoliated using the standard Scotch Tape technique (see graphene) and used for the fabrication of a field-effect transistor. High-yield synthesis of HfS2 has also been demonstrated using liquid phase exfoliation, resulting in the production of stable few-layer HfS2 flakes. Hafnium disulfide powder can be produced by reacting hydrogen sulfide and hafnium oxides at 500–1300 °C.

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<span class="mw-page-title-main">Zirconium(III) iodide</span> Chemical compound

Zirconium(III) iodide is an inorganic compound with the formula ZrI3.

Hafnium compounds are compounds containing the element hafnium (Hf). Due to the lanthanide contraction, the ionic radius of hafnium(IV) (0.78 ångström) is almost the same as that of zirconium(IV) (0.79 angstroms). Consequently, compounds of hafnium(IV) and zirconium(IV) have very similar chemical and physical properties. Hafnium and zirconium tend to occur together in nature and the similarity of their ionic radii makes their chemical separation rather difficult. Hafnium tends to form inorganic compounds in the oxidation state of +4. Halogens react with it to form hafnium tetrahalides. At higher temperatures, hafnium reacts with oxygen, nitrogen, carbon, boron, sulfur, and silicon. Some compounds of hafnium in lower oxidation states are known.

<span class="mw-page-title-main">Hafnium(III) iodide</span> Chemical compound

Hafnium(III) iodide is an inorganic compound of hafnium and iodine with the formula Hf I3. It is a black solid.

References

  1. 1 2 3 4 5 Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.66. ISBN   1-4398-5511-0.
  2. 1 2 3 Krebs, B.; Sinram, D. (1980). "Hafniumtetrajodid HfI4: Struktur und eigenschaften. Ein neuer AB4-strukturtyp". Journal of the Less Common Metals. 76 (1–2): 7–16. doi:10.1016/0022-5088(80)90005-3.