The exciton spectrum of AgI, CuI, CuBr, and CuCl is discussed and various peaks attributed to several coexisting crystal modifications. The shift of the peaks with alloy concentration in the pseudobinary systems formed with these compounds is reported and interpreted. The absorption and reflection spectra of these materials and their alloys for energies between the energy gap and 10 eV is reported and the structure attributed to transitions between regions of the valence band lying below the highest maximum and parts of the conduction band higher than the lowest minimum. These spectra are compared with the corresponding spectra of other zincblende- and wurtzite-like materials.

Optical Properties of the Silver and Cuprous Halides

Coordination stabilised copper(I) flouride. Crystal and molecular structure of fluorotris(triphenylphosphine)copper(I)·ethanol (1/2), Cu(PPh3)3, P·2EtOH

Halogens and many halogen compounds are very corrosive. In fact, iodine was discovered when, as an impurity in soda ash, it caused corrosion of copper vessels.1 Hence, materials for containing and handling halogens and corrosive halogen compounds must be selected with particular care.

Halogen Corrosion of Metals

Our attempts to synthesize the hitherto unknown binary copper(I) fluoride have led to first successes and a serendipitious result: By conproportionation of elemental copper and copper(II) fluoride in anhydrous liquid ammonia, two copper(I) fluorides were obtained as simple NH3 complexes. One of them presents an example of ligand-unsupported "cuprophilic" interactions in an infinite [Cu2 (NH3 )4 ](2+) chain with alternating Cu-Cu distances. We discovered that both copper(I) fluorides can easily be converted into Cu3 N at room temperature, just by applying a vacuum. Additionally, we investigated the formation mechanism of the classical synthesis route of Cu3 N that starts with CuF2 and flowing NH3 in the temperature range between ambient and 290 °C by means of thermal analysis and in situ neutron diffraction. The reaction proceeds at elevated temperatures through the formation of a blue and amorphous ammoniate Cu(NH3 )2 F2 , the reformation of CuF2 , and finally the redox reaction to form Cu3 N.

https://research.aalto.fi/files/8082971/On_Copper_I_Fluorides.pdf

On Copper(I) Fluorides, the Cuprophilic Interaction, the Preparation of Copper Nitride at Room Temperature, and the Formation Mechanism at Elevated Temperatures

K. Little

Papers

The copper fluorides: Part I—X-ray and electron microscope examination