Hydroxyl-rich (Cu-LF) and Fluorine-rich (Cu–HF) copper hydroxyfluorides Cu(OH)2-xFx (x = 0.4–0.5 and x = 0.9–1.5) were prepared by precipitation route followed by hydrothermal process where the starting pH and the HF molar content play a key role. Based on powder XRD and PDF analysis, long range and short order were evidenced with various Cu–O/F bondlengths illustrating the Jahn-teller distortion as well as the Cu–Cu intra-sheet and interslab interactions. Tuning the fluorine content allows chemical bonding modulation by antagonist effect, resulting for instance in the weakening of H bonding in the hydroxyl-rich compound. When the fluorine content increases, the average structures evolve from a disordered network with a random distribution of anions in the vicinity of Cu2+ in Cu-LF to a well ordered mixed anions phase where Cu(OH)3F3/Cu(OH)2F4/Cu(OH)5F distorted octahedra are close to C2h point group symmetry. Raman spectroscopy confirm the average structural features with the point group symmetry. One should outline in Cu–HF composition, stronger CuF3(OH)3 octahedron stiffness associated to a stretching O–H mode at lower frequency, synonymous of O–H bond weakening and consequently stronger hydrogen bonding in agreement with PDF analysis. UV–visible–NIR spectra show in Cu–HF hydroxyfluoride, an increase of the optical band gap of 0.6 eV and a decrease of Cu2+(3 d9) crystal field splitting of 0.1 eV in agreement with the larger fluorine content. However, the dxz-dyz orbital splitting increases of 0.2 eV in Cu–HF in good agreement with the C2h point group symmetry and the related distortion. Finally, whereas the hydroxyl-rich Cu-LF phase decomposes into CuO at T > 300 °C, the Fluorine rich Cu–HF compound lead at T > 320 °C to the formation of CuF2, Cu2O in addition to CuO. This unusual reduction process Cu2+ → Cu+ at low temperature is associated to the strengthening of Cu–O/F and Cu–Cu bonding in the basal plane of Cu(OH)3F3 distorted octahedron.< Leer menos