Leonid Fedorovich Vereshchagin (29.04.1909—20.02.1977) was a Soviet physicist and an academician (1966; corresponding member 1960). He was born in Kherson. He graduated from Odessa University (1928). He began working (1926) at the Institute of Physics of Odessa University. In 1930 — 39 he worked at the Physico-Technical Institute of the Academy of Sciences of the Ukrainian SSR (Kharkov), and in 1939-54 he was head of a laboratory at the Institute of Organic Chemistry of the USSR Academy of Sciences. From 1954 he was director of the High Pressure Laboratory of the USSR Academy of Sciences, and from 1958 of the Institute of High Pressure Physics of the USSR Academy of Sciences. From 1953 he was also head of the department of the physics and chemistry of high pressures at Moscow University, and from 1973 head of the department of high-pressure physics at the Moscow Institute of Physics and Technology.
His main research concerned the physics and technology of ultra-high pressures, the physical properties of solids, methods of measuring various physical quantities at these pressures, and high-pressure chemistry.
He carried out a large body of work on the study of chemical reactions at high pressures and temperatures — the rates of polymerisation reactions, catalytic properties, the characteristics that affect the efficiency of the synthesis of new substances, and the physical properties of a number of organic compounds (USSR State Prize, 1952).
Together with his co-workers he developed methods of generating high pressures and the corresponding apparatus. He studied the phase diagrams of a whole range of elements and compounds over a wide interval of pressures, and in particular made a detailed study of the phase diagrams and structures of the elements of the third and fifth groups and of the fluorides of the transition metals. As a result the sequence of polymorphic transformations as the pressure increases was established, and polymorphic transitions were detected that involve a radical change of the crystal structure, an increase of the coordination number and a marked decrease of volume. Together with his co-workers he synthesised (1960) diamond and its superhard analogue, cubic boron nitride (Lenin Prize, 1961). He obtained pressures of up to 3 Mbar and detected, in the megabar range of pressures, the transition of diamond, silica, corundum, water, solid hydrogen and other substances into the conducting state. He carried out the synthesis of new superconducting dense modifications of a number of carbides and nitrides of the transition metals and of rare-earth sulfides. He contributed to the development of the extrusion of solids at high pressures, and in particular developed a method of gas extrusion.
Hero of Socialist Labour (1963).