INTRODUCTORY REMARKS (A brief description of the participating institutions in the Seminar and scientific activities)

The Seminar was organized by the Institut d ' Estudis Catalans and the Institute of Crystallography of Moscow . The Centres of Barcelona which gave access to their laboratories and collaborated with some research papers were : Department of Crystallography, Mineralogy and Mineral Deposits , and Department of Fundamental Physics of the Barcelona University ; Department of Chemical Engineering and Group of Macromolecular Structures of Polytechnic University of Catalonia ; Material Sciences Institute of Consejo Superior de Investigaciones Cientificas (CSIC). The lectures and research papers offered at the seminar were divided in three groups in accordance with their field : structure of crystals , methods and applications; non-stoichiometry and phases in fluorites and the crystal properties of superionic conductors ; and macromolecules. Professors B. K. Vainshtein and B . V. Sobolev gave a lecture on their specific topics, proteins and the non-stoichiometry of fluorites . Professors V. I. Simonov, X. Solans and J. A. Subirana gave a short lectures on the problems to obtain good results and new conclusions in their Institutes. [Butll. Soc. Cat . Cien.j, Vol. X11, Num. 2, 1991