Gadolinium diiodide is an

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

, 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 GdI₂. 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 ...

, with the ionic formula of Gd³⁺(I⁻)₂e⁻, and therefore not a true gadolinium(II) compound. It is

ferromagnetic Ferromagnetism is a property of certain materials (such as iron) which results in a large observed magnetic permeability, and in many cases a large magnetic coercivity allowing the material to form a permanent magnet. Ferromagnetic materials ...

at 276 K with a saturation magnetization of 7.3 B; it exhibits a large negative

magnetoresistance Magnetoresistance is the tendency of a material (often ferromagnetic) to change the value of its electrical resistance in an externally-applied magnetic field. There are a variety of effects that can be called magnetoresistance. Some occur in bulk ...

(~70%) at 7 T near room temperature. It can be obtained by reacting gadolinium and gadolinium(III) iodide at a high temperature: : Gd + 2 GdI₃ → 3 GdI₂ It can react with hydrogen at high temperature (800 °C) to obtain gadolinium hydrogen iodide (GdI₂H_0.97).

References

{{Lanthanide halides Gadolinium compounds Iodides Electrides Ferromagnetic materials Lanthanide halides