Lanthanum diiodide is an iodide of

lanthanum Lanthanum is a chemical element with the symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lantha ...

, with the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

of LaI₂. It is an

electride An electride is an ionic compound in which an electron is the anion. Solutions of alkali metals in ammonia are electride salts. In the case of sodium, these blue solutions consist of a(NH3)6sup>+ and solvated electrons: :Na + 6 NH3 → a(N ...

, actually having a chemical formula of La³⁺ I⁻)₂e⁻

Preparation

Lanthanum diiodide can be obtained from the reduction of

lanthanum(III) iodide Lanthanum(III) iodide is an inorganic compound containing lanthanum and iodine with the chemical formula . Synthesis Lanthanum(III) iodide can be synthesised by the reaction of lanthanum metal with mercury(II) iodide: :2 La + 3 HgI2 → 2 LaI3 + ...

with

metal under a

vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often dis ...

at 800 to 900 °C: : It can also be obtained by reacting

and

mercury(II) iodide Mercury(II) iodide is a chemical compound with the molecular formula Hg I2. It is typically produced synthetically but can also be found in nature as the extremely rare mineral coccinite. Unlike the related mercury(II) chloride it is hardly solu ...

: : It was first created by

John D. Corbett John is a common English name and surname: * John (given name) * John (surname) John may also refer to: New Testament Works * Gospel of John, a title often shortened to John * First Epistle of John, often shortened to 1 John * Second E ...

in 1961.

Properties

Lanthanum diiodide is a blue-black solid with metallic lustre, which is easily

hydrolyzed Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

into the iodide oxide. It has a MoSi₂-type structure, with the space group ''I''4/''mmm'' (No. 139).

References

{{Lanthanide halides Lanthanum compounds Iodides Electrides Substances discovered in the 1960s