cui

Copper(I) iodide, CuI, is an inorganic compound used as a reagent in chemistry and materials science. It appears as a white to pale yellow crystalline solid and has a high melting point. CuI is sparingly soluble in water, but in iodide-rich solutions it can form soluble complex species such as [CuI2]-, increasing apparent solubility.

In terms of structure and properties, CuI adopts the zinc blende (sphalerite) crystal structure at room temperature, with each Cu+ tetrahedrally coordinated by four I- ions and each I- surrounded by four Cu+. CuI is a p-type semiconductor with a wide band gap of about 3.1 eV. It is relatively stable in air under ambient conditions but can slowly react in the presence of strong oxidants.

Preparation of CuI typically involves direct heating of copper metal with iodine (Cu + I2 → CuI) or precipitation from copper salts with iodide in the presence of a reducing agent. In aqueous iodide media, CuI can form soluble polyiodide complexes, reflecting its chemistry in different environments.

Applications of CuI include catalysis and materials science. It is a widely used catalyst for azide-alkyne cycloaddition (CuAAC), enabling the synthesis of 1,4-disubstituted triazoles under mild conditions. CuI also serves as a precursor to copper(I)-based materials and is studied for semiconductor and optoelectronic applications, including thin films and nanostructures.

Safety considerations: CuI is toxic if ingested and can cause irritation to eyes and skin. Handle with appropriate protective equipment, avoid inhalation of dust, and store away from oxidants and moisture following standard laboratory practices.