Verdampfung von Kupfer(II)chlorid und Struktur des Dampfes untersucht mit UV./VIS.‐ und Raman ‐Spektroskopie

The vapour pressure of CuCl 2 and the dimerization of CuCl 2 (g) have been investigated by optical spectroscopy in the range 420–650°C, p   Cl   2= 0.5‐5 atm. The enthalpy of dimerization of CuCl 2 (g) was determined by visible and by Raman spectroscopy and good agreement was found (−154 kJmol −1 and −143 kJmol −1 ). CuCl 2 (g) shows two totally symmetric Raman modes (373 and 127 cm −1 ) indicating that, at least at elevated temperatures, CuCl 2 (g) is not a linear molecule. The optical spectra of Cu 2 Cl 4 (g) and CuLCl 5 (g) (L Ga, In) are very similar supporting a CuCl 3 ‐chromophor in both cases. The formerly proposed structure of CuL 2 Cl 8 (g) (L Al, Ga) contains bridging and terminal chlorides, structural elements also present in Cu 2 Cl 4 (g). In agreement with the proposed structure v   Cu‐Cl   termis identical in Cu 2 Cl 4 (g) and CuL 2 Cl 8 (g), while V   Cu‐Cl   bridg.is at lower energies (20–30 cm −1 ) in CuL 2 Cl 8 (g) than in Cu 2 Cl 4 (g).