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The composition LaNi_0.5Cu_0.5O_3−δ has been prepared by heat treating a polyacrylamide xerogel in flowing O₂. A perovskite type structure starts to crystallise at 700 °C and is achieved at 1000 °C. TGA data point to the formation of a rather strongly oxidised compound (δ ≤ 0.09). As the solid state reaction of a mixture of La₂O₃/NiO/CuO powder oxides never yields a perovskite, the part of the sol–gel route in this synthesis proves to be crucial. On the basis of X-ray and neutron diffraction results, the existence of a cupronickelate having a rhombohedral perovskite type structure is proved. Rather unexpectedly, an electron diffraction study of the as-prepared composition at 1000 °C reveals the presence of two sets of perovskite type cupronickelate microcrystals: a copper rich one with a fixed composition 67% Cu and a nickel rich one with a small range of compositions 59 ≤ Ni% ≤ 67. The latter microcrystals feature the rhombohedral LaNiO₃ perovskite whereas the former one, due to the partial presence of Cu(ii), frequently shows an orthorhombic [2a_p√2 × 2a_p√2 × a_p] supercell. Thus, the composition LaNi_0.5Cu_0.5O_3−δ. has to be understood in terms of a nanoscale segregated pseudo solid solution formed of two lanthanum cupronickelates, enriched in copper and nickel, respectively.

The adsorption of the cationic oxidized safranine S+by a Na+, Ni2+and Fe3+montmorillonite has been studied with X-ray powder diffraction, u.v., visible and i.r. spectroscopy. In solution S+may be protonated: S+, SH2+and SH23+have characteristic spectra in the 500–600 nm region where the clay structure does not absorb. In the Na+as well as in the Ni2+and Fe3+clays, the adsorption of S+is a cation exchange process accompanied by the protonation of the adsorbed dye such as variable concentrations of M+(Na+, Ni2+or Fe3+), S+and SH2+are simultaneously present. Protonation activity decreases from Fe3+to Ni2+and Na+, being the protonation site the amine group as shown by i.r. In the interlamellar space it seems that a SH2+.. S+association exists that could be described as a sandwich structure 6.5 Å thick.

The temperature variation of the thermal conductivity, the electrical resistivity and the thermoelectric power of a graphitized polyimide film has been measured in the temperature range 2 < T < 300 K. The effect of electrochemical intercalation with FeCl4- ions has also been studied. The thermal conductivity results confirm the high degree of graphitization that may be obtained with polyimide films. It shows how intercalation increases the structural disorder and how the intercalate substantially contributes to the thermal conductivity at low temperatures. The electrical-resistivity and thermoelectric-power measurements reveal that the density of free carriers is about three times lower in stage-2 FeCl4- solvated intercalation compounds obtained by an electrochemical way than in stage-2 FeCl3 compounds synthetized by a classical method.

FeCl4- graphite intercalation compounds (GIC) were obtained by anodic oxidation of graphite in an aqueous solution and were subsequently submitted to galvanostatic reduction in a:Li / LiClO4 1M in propylene carbonate/GIC cell.The intensiostatic and structural data were compared to those obtained on partly reduced 2nd stage FeCl3 GIC. Whereas a "one step reduction" is observed with the FeCl3 GIC, the reduction of the 2nd stage FeCl4 GIC takes place with at least four well defined plateaus. The beginning of the last step corresponds to a stable 6 th stage structure. Increasing the charge passed through the samples leads to the exfoliation of the graphitic lattice and to the formation of metallic iron, exhibited by important ferromagnetic susceptibility.

Highly oriented pyrolytic graphite was fluorinated at room temperature with molecular fluorine at 2.5 atm for 8 days to 2 months without addition of any catalyst. Under these mild conditions we obtained graphite-fluorine intercalation compounds in a wide range of stoichiometry 64 ⩾ C/F ⩾ 4. Except for the highest fluorine content (C/F ⩽ 4) all our samples are better conductors than graphite. A thorough XPS study of clean cleaved internal surfaces of the oriented samples shows a new kind of carbon-fluorine bonding. The binding energies of the C1sand F1sphotoemission peaks are 287.3 ± 0.2 and 685.7 ± 0.2 eV. These values differ from those of typical covalent bonds (290.4 and 689.6 eV) and the nature of the bond is probably different from that of covalent C-F.