The crystal and electronic structures of the orthorhombic compound UCoGe are presented and discussed. It has been either refined by the x-ray diffraction on a single crystal or computed within the local spin density functional theory, employing the fully relativistic version of the full-potential local-orbital band structure code, respectively. We particularly give our attention to investigating the Fermi surface and de Haas-van Alphen quantities of UCoGe. The calculated electronic density is then examined by x-ray photoelectron spectroscopy (XPS). Fairly good agreement is achieved between theoretical and experimental XPS results in the paramagnetic state. A small difference in the position (in energy scale) of the U 5f bands is caused by the electron localization effect observed in the experimental XPS. There is also some discrepancy for the Co 3d electron contributions below E(F). The Fermi surface in the non-magnetic state is of a semimetallic type while that in the ferromagnetic state, with the ordered moment of -0.47 μ(B)/f.u. along the c axis, is more metallic, with nesting properties that may favour superconductivity.

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Zn 1-x Co x Al 2 O 4 (x = 0, 0.5, 1.0) spinels were synthesised under microwave-assisted solvothermal conditions using 1,4-butanediol as reaction medium. The results of XRD and HRTEM have indicated nanocrystallinity of prepared materials (average crystallite size in the range 6-16 nm), and N 2 adsorption-desorption measurements have revealed high feature of their surface area and mesoporous nature. Acid-base properties of prepared materials were determined using TPD-NH 3 method and cyclohexanol test. All studied spinels that underwent examination were active in phenol methylation but Co-substituted zinc aluminate (Zn 0.5 Co 0.5 Al 2 O 4 ) was found to be the most efficient in the selective formation of orthomethylated products. It could be ascribed to its dominant basic character and the presence of weak and strong acid centres, and the highest surface area as well.

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