Chromium(III) iodide, also known as chromium triiodide, is an inorganic compound with the formula . It is a black solid that is used to prepare other chromium iodides. Like the

isomorphous In mathematics, an isomorphism is a structure-preserving mapping between two structures of the same type that can be reversed by an inverse mapping. Two mathematical structures are isomorphic if an isomorphism exists between them. The word is ...

chromium(III) chloride Chromium(III) chloride (also called chromic chloride) describes any of several chemical compounds with the formula CrCl3, where can be 0, 5, and 6. The anhydrous compound with the formula CrCl3 is a violet solid. The most common form of the tric ...

(), chromium(III) iodide exhibits a cubic-closest packing arrangement in a double-layer crystal lattice. In this structure, chromium exhibits

octahedral coordination geometry In chemistry, octahedral molecular geometry, also called square bipyramidal, describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The oc ...

Preparation and properties

Chromium triiodide is prepared by the direct reaction of chromium metal with an excess of iodine. The reaction is conducted at 500 °C: : To obtain high purity samples, the product is thermally decomposed at 700 °C to sublime out chromium(II) iodide. The diiodide is then reiodinated. Chromium triiodide is stable in contact with

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

and

moisture Moisture is the presence of a liquid, especially water, often in trace amounts. Small amounts of water may be found, for example, in the air (humidity), in foods, and in some commercial products. Moisture also refers to the amount of water vapo ...

, but at temperatures approaching 200 °C it reacts with oxygen and releases iodine. Like , the triiodide exhibits slow solubility in water owing to the kinetic inertness of Cr(III). Addition of small amounts of chromous iodide accelerates the dissolving process. Chromium triiodide can also be prepared as nanoplatelets from the alkoxide . Chromium triiodide was one of the first materials which was discovered to be a magnetic two-dimensional material that has great potentials for

spintronics Spintronics (a portmanteau meaning spin transport electronics), also known as spin electronics, is the study of the intrinsic spin of the electron and its associated magnetic moment, in addition to its fundamental electronic charge, in solid-st ...

devices.

References

Chromium(III) compounds Iodides Metal halides {{inorganic-compound-stub