Crystallography in Russia
Shubnikov Institute of Crystallography, Russian Academy of Sciences: 1940-2000
Foundation of the Institute
Development of scientific directions
The Institute of Crystallography was actively engaged in the fields of crystal symmetry and morphology, X-ray diffraction analysis, crystal growth and the synthesis of quartz. In 1939, N.N. Sheftal suggested a method for growing large crystals of Rochelle salt and high-quality piezoelectrics necessary for constructing sensitive piezoelectric devices for use in the war. In the 1940s, Shubnikov put forward a concept of antisymmetry for studying magnetic properties of crystals and N.V. Belov composed a theory of close packings and performed detailed X-ray diffraction analysis of the atomic structures of silicate minerals. In 1945, G.G. Lemmlein found a spiral relief in crystal faces associated with the helicoidal structure of the crystal lattice. Methods for studying crystal structure were being rapidly developed at the Institute. Vainshtein used Fourier synthesis to calculate the distribution of electrostatic potentials in crystal lattices based on experimental electron diffraction data (1949). Vainshtein and Z.G. Pinsker determined the structure of paraffin, and the localized hydrogen atoms within it. In the 1950s, S.A. Semiletov and coworkers obtained fundamental results on the mechanism of homoepitaxial growth of thin germanium films. At the same time S.K. Popov designed an automated industrial apparatus for growing ruby rods. In 1940s-1950s, N.V. Belov and his coworkers initiated studies on the crystal chemistry of silicates related to geochemical and geophysical processes and the production of cements, glasses, and ceramics. Their studies were used to develop low-temperature cement and new types of concrete. In 1951, Shubnikov published Symmetry and Antisymmetry of Finite Figures, in which he discussed the notion of four-dimensional crystallography.
B.N. Grechushnikov, in cooperation with G.I. Distler, worked on the theory of Fourier-spectroscopy and designed and constructed a Fourier spectrometer. This instrument obtained well-resolved illumination light spectra from the Saturn disk and rings.
In 1962, the group, headed by Kh.S. Bagdasarov, built a stably operating laser. In 1972, laser radiation from chromium ions in garnets was achieved. At the beginning of the 1960s, the scientists of the Institute determined the structures of synthetic analogues of a protein (a complex polypeptide), crystallized enzymes into tubes with monomolecular walls, and determined the structure of leghemoglobin. In the 1980s, the scientists of the Institute developed an experimental approach to high-pressure studies of crystals using diamond anvils, increasing the range of attainable pressures (up to 100 GPa) and broadening the spectrum of problems solvable by this method.
Fundamental studies in the theory of dislocations, the physics of plasticity, the theory of phase transitions in crystals, and the theory of symmetry were pursued. In particular, the existence of improper phase transitions was predicted. The studies of the statistical kinetics of spiral-layer crystallization helped to clarify many processes. In 1990s the scientists of the Institute developed the theory of electrooptical and ferroelectric properties of liquid crystals and designed many applicable devices.
Development of technology of crystal synthesis
L.M. Belyaev and his coworkers studied the synthesis of organic and inorganic crystal-scintillators with high scintillation efficiency. In the 1960s, A.A. Shternberg worked out the industrial synthesis of a rock crystal, piezoelectric quartz.
A method for horizontal crystallization for growing refractory single crystals was developed along with the technologies for growing large almost perfect single crystals of yttrium-aluminum garnet, sapphire, and yttrium aluminate. Industrial facilities for growing single crystals were constructed.
Methods of the thermal-compression junction and creation of solid-phase junctions of laser crystals that guarantee high optical quality of the interfaces were developed. New crystallization apparatus for growing crystals in space were also constructed, and crystallization experiments were performed on water-soluble crystals under the conditions of microgravity at the Salyut-5 orbital station (1976).
A series of specialized diffractometers have been designed at the Institute including the TRS triple-crystal X-ray diffractometer, the KARD-4 automated coordinate X-ray diffractometer, the RED-EL four-circle X-ray diffractometer, the DAR family of automated X-ray diffractometers, and the AMUR series of X-ray small-angle diffractometers. An automated 512-channel diffractometer for proteins was also constructed. In cooperation with the Laboratory of High Energies of the Joint Institute for Nuclear Research (JINR) in Dubna, a two-dimensional proportional chamber for the automated KARD diffractometer for studying protein single crystals was designed. Methods for studying polycrystalline materials, polymers and liquid crystals in X-ray diffractometers with two-dimensional detectors were also developed.
The Institute of Crystallography in the 21st century
New scientific priorities
At present, the Shubnikov Institute is focusing on the following problems:
- Creation of new crystals, films, and structures with specific properties;
- The study of the structures and properties of condensed matter using X-ray and synchrotron radiation, neutrons, and electrons;
- Further development of existing instruments and methods and creation of new ones;
- Study of properties of biological materials and organic systems;
- Study of condensed matter under microgravity;
- Study of surfaces, subsurface layers, interfaces, thin films, and track membranes;
- Development of X-ray optics; and
- Design and construction of apparatus for crystal growth.
The Institute also participates in the following projects of the Federal Scientific and Technological Program:
- Physics of Radiation,
- Condensed Matter,
- High-Precision Measurements,
- Quantum and Nonlinear Processes,
- Physics of Solid Nanostructures,
- Information Technologies and Electronics,
- New Materials and Chemical Products,
- Scientific Instrument Engineering.
Within the framework of the Russian Academy of Sciences, the Institute performs work on laser systems, strongly correlated electrons, nanomaterials and nanotechnologies. The Institute of Crystallography participates in the Federal Space Program of Russia.
Shubnikov participated in the organization of the lUCr and suggested the title Acta Crystallographica for its printed edition. Belov served as the IUCr President from 1966 to 1969, Vainshtein and V.I. Simonov were Vice-Presidents in 1975-1978 and 1984-1987, respectively. The Institute of Crystallography cooperates with more than twenty foreign scientific organizations participating in numerous interacademic and interinstitute agreements. The Institute holds annual Shubnikov, Vainshtein, and Belov lectures.
M.V. Kovalchuk and S.I. Zheludeva used fluorescence in the range of total external reflection of X-rays for localization of ions inside organic multilayers. The study of protein-lipid systems on liquid surfaces and solid substrates revealed the effect of drugs on heavy atom positions. Today scientists at the Institute actively use synchrotron radiation in many fields of modern crystallography and they play a leading role in researches at Kurchatov Center of Synchrotron Radiation (KCSR).
Studies of the semiconductor Inx Ga1-x As/GaAs demonstrated the value of X-ray diffraction in characterization of multilayer systems including determination of the thickness and compositions of individual layers, interface structures, and defects in the layers. Computer simulation of the growth of icosahedral quasicrystals has been performed. New types of diffraction reflections in crystals of germanium and a germanium-silicon alloy have been predicted. Defects arise because of distortion of the electronic state of germanium atoms by thermal vibrations and point defects. Such reflections have been observed in technologically important crystals and alloys. The group, headed by N.A. Kiselev, used high-resolution electron microscopy to study nanotubes with multilayer cylindrical walls and walls consisting of conic graphene layers and surface-modulated walls. L.A.Feigin's laboratory had a large contribution in the development of small angle scattering methods (theory, experiments and instrumentations) in application of X-R reflectometry in the study of different bioorganic materials.
Shortly before the 60th Jubilee of the Institute, a newly discovered mineral was officially named IKRANITE by the International Mineralogical Assn. Five other minerals have been named after scientists of the Institute: shubnikovite, belovite, lemmleinite, stishovite, and rastsvetaevite. The Institute regularly holds national conferences on crystal growth and annual schools on electron microscopy.
New crystalline media
(a) Silicon whiskers, (b) HREM image of a nanodimensional tip.
A Gd-containing fast scintillator has been suggested in the fluoride family (together with the Russian Research Center Kurchatov Institute). Such a scintillator is very promising for recording low-energy neutrinos. Langasites, a new family of highly efficient piezoelectrics, has been discovered by Pisarevsky's group in cooperation with Moscow State University.
Bioorganic materials science
Studies of physical properties
Active lithium niobate (a nonlinear optical material) was found to have impurities (Mg, Zn, In, etc.). By varying the doping level, it is possible to vary these properties. Magnetically stimulated strengthening of crystals manifests itself as a decrease in the dislocation mobility under the joint action of an applied mechanical load and a magnetic field. Atomic force microscopy (AFM) was found to be an efficient way to study the domain structure of polar surfaces of ferroelectrics. Analysis of the data revealed the effect of crystal-lattice distortions on dislocation mobility and a new type of dynamics of plastic flow in crystalline materials.
Track membranes allow one to create tip electrode nanostructures that release molecular hydrogen 100 times more intensely than traditional electrode systems. The Institute has obtained new products based on track membranes including systems for monitoring drinking water, systems of track-pore room and respirators based on the principle of diffusion gas exchange, tip structures for Raman spectroscopy and for increasing heat removal from reactor surfaces, and membranes for purification of crystallization solutions.
The experience of the Institute in solid-state physics and the development of technologies of crystal growth paved the way for participation in the State project on the development of an industry of synthetic dielectric crystals and their products. About twenty Russian institutes, industrial enterprises and companies participate in this project. The Institute coordinates the development of new instruments and technologies for the production of synthetic dielectric crystals. The new technology is based upon fundamental advances made by the Institute and benefit from past experience and industrial achievements in the field of growth and processing of crystals, and the manufacture of various crystal-based products.
Inorganic Crystal Chemistry at Moscow State University
The laboratory's goals involve the synthesis of new compounds, determination of their three-dimensional structures and correlation of structure and properties. Powder diffraction is used for phase analysis and cell parameter determination, followed by structure solution from either powder or single crystal X-ray data (XRD). For problem cases electron diffraction (ED) together with high resolution electron microscopy (HREM) and/or neutron diffraction are used. Sometimes other methods help to answer specific questions on structural details, and throughout the process measurements of physical properties are performed by collaborators.
The targets of study over the years have been mainly complex oxides. Intensive studies of superconducting complex cuprates in 1987 resulted in the discovery of a family of mercury based cuprates that exhibits the highest known transition temperature. In 1994, this work received the Lomonosov Award of the Moscow State University and the Superconductivity Award of Excellence given by the World Congress on Superconductivity. Our discoveries have included various superconducting copper based oxides, oxycarbonates, oxyfluorides, and superconducting bismithates. When Sr1-xKxBiO3 was synthesized under high pressure it was found that both the symmetry of the unit cell and its superconducting properties depend on potassium content. The highest superconducting transition temperature was found for the composition Sr0.44K0.56BiO3 when the phase crystallizes in a tetragonal unit cell.
The search for substances with colossal magnetoresistance effects resulted in the synthesis of A2GaMnO5+δ (A=Sr, Ca, δ ≤ 0.5) phases for the first time. These phases undergo interesting structural and magnetic phase transitions during the oxidation process. It has been shown that compounds with a Brownmillerite type structure crystallize in different space groups. Only the use of electron microscopy and a 3+d dimensional crystallographic approach helped to describe their structures correctly. The space group depends on the orientation of tetrahedral GaO4 chains and their ordering in adjacent layers. Sometimes, such ordering occurs in a rather complicated manner forming commensurately modulated structures. For the Sr and Ca phases the insertion of extra oxygen resulted in the suppression of Jahn-Teller distortion for MnO6 octahedra, a change of Ga coordination from tetrahedral to octahedral, and an increase of unit cell symmetry from orthorhombic to tetragonal.
The study of complex cobalt oxides as potential mixed conductors led to the discovery of Sr0.7Y0.3CoO2.62 which has a perovskite-related crystal structure. Its tetragonal unit cell is formed of alternating cobalt oxygen layers. Half of the layers consist of CoO6 octahedra, others are oxygen deficient tetrahedra with one additional oxygen at the long distance. The structure is considered as intermediate between brownmillerite and perovskite.
Many of these studies would not have been possible without our collaborators. We are grateful to Arne Magneli and Lars Kihlborg (Stockholm University) who were very helpful during the early 90's, a difficult time for Soviet and Russian science. Massimo Marezio and his colleagues (CNRS, France) have been collaborators in the syntheses and structural studies of superconducting complex copper oxides. Phillip Coppens (SUNY, USA) and Vaclav Petricek (Institute of Physics, Czech Rep.) helped us to understand what modulated structures are. Electron diffraction and high resolution electron microscopy studies are still carried out with Gustaaf Van Tendeloo and co-workers (EMAT, Belgium). Structure refinements from neutron data are based on experiments done in Dubna in the Joint Institute on Nuclear Research by the group of Anatoly Balagurov.
Information about the Inorganic Crystal Chemistry Laboratory can be found at www.icr.chem.msu.ru .
Contact: Evgeny Antipov (firstname.lastname@example.org)
Structural Chemistry, Moscow State UniversityUnder the direction of Leonid A. Aslanov (email@example.com), four main directions of research are being pursued in the Laboratory of Structural Chemistry at Moscow State University:
A. The laboratory is involved in the development of methods for structural characterization of polycrystalline materials from powder data in collaboration with H. Schenk (University of Amsterdam). Two molecular structures solved recently from powder diffraction data demonstrate our achievements in this area.
2. Elucidation of three-dimensional solid state structures of two modifications of doxazosin mesylate, a commonly used antihypertensive agent, clearly showed the N1 protonation site in anhydrous (A) and hydrated (dG) solid forms, establish the conformations of the doxazosin molecule and define the hydrogen bonding in both forms.
Contact: Vladimir V. Chernyshev (firstname.lastname@example.org)
Contact: Victor A. Tafeenko (email@example.com)
Contact: Victor B. Rybakov (firstname.lastname@example.org)
D. A number of the traditional dyes and pigments, as well as modern materials for electrooptical and photonic applications and laser dyes, have been studied by means of single crystal and powder X-ray diffraction. Main research directions are the following: tautomeric interconversions in the solid state; intermolecular charge-transfer interactions and π-complexes; crystal packing effects on spatial and electronic molecular structure; crystallochromism, i.e. the difference in color of solid pigments due to molecular packing arrangements.
 Zhukov, S.G. et al. (2001). Z. Kristallogr. 216, 5-9.  Chernyshev, V.V. et al. (2001). Acta Cryst. C57, 982-984.  Chernyshev, V.V. et al. (2003). Acta Cryst. B59, 787-793.  Tafeenko, V.A. et al. (2003). Acta Cryst. C60, o62-o64.
Crystallography in Physics, Moscow State University
The current chair, A.S. Ilyushin, is a leader in the field of education programs on condensed matter among Russian Universities. The program combines the teaching of experimental methods (X-ray, Mossbauer etc.) with basic principles of solid state physics (atomic, electronic and defect structures of crystals, dynamics of the crystal lattice, and phase transformations).
From the 1940s through the 70s a group under M.M. Umansky developed an experimental set for X-ray studies of crystal structure which also won a Lomonosov Prize (M.M. Umansky, S.S. Kvitka, and V.V. Zubenko). Recent research has included the development of new methods of X-ray and Mossbauer structure analysis of ideal and real crystals and application of these methods to studies of phase transformations and defects in metals, alloys, semiconductors and multi-layer films; evolution and self-organization of crystals and their electronic structure; and non-equilibrium phenomena and surface layers. Significant results have included:
a) A non-monotonic structural evolution, including a discrete (jump) evolution in the non-equilibrium metal-hydrogen systems was discovered, and a synergetic model was proposed (A.A. Katsnelson, G.P. Revkevich, and V.M. Avdyuhina).
b) An effect of internal magnetostriction in the rare-earth intermetallic compounds was found and its atomic-ionic mechanism was estimated (A.S. Ilyushin).
c) X-ray and Mossbauer diffraction near-edge spectroscopy of crystals and multi-layer films allowed depth-selective studies of atomic and magnetic structure (R.N. Kuzmin, V.A. Bushuev, M.A. Andreeva, and E.N. Ovchinnikova).
d) A wave theory was proposed for 3D internal structure reconstruction in low-absorption non-crystals based on phase-contrast X-ray refraction tomography, featuring orders of magnitude higher image contrast and 1-2 orders lower dose of absorbed radiation (V.A. Bushuev, patented method).
e) Molecular dynamics simulation and ab initio electronic structure calculations were used to study the formation of adsorbed nanostructures on metal surfaces and to predict the physical properties of surface layers (A.A. Katsnelson and V.S. Stepanyuk).
Contact: Albert A. Katsnelson (email@example.com)
Crystallography and Crystal Chemistry of Geology, Lomonosov Moscow State University
A central point in the domain of theoretical crystal chemistry is occupied by the development of energetic analysis of stability and properties of pure crystals and solid solutions. Recent activities of the group (V.S. Urusov, N.N. Eremin) have concentrated on the problem of computer modeling of structures and properties of mineral and inorganic solids using semi-empirical interatomic potentials as well as on the development of atomistic and phenomenological theory of isomorphous substitutions. Their original approach is minimization of crystal atomisation energy which accounts for the actual character of chemical bonds in crystals.
Contact: Vadim S. Urusov (firstname.lastname@example.org)
Crystal Chemistry, Lomonosov Moscow State University (MSU)
- The history of the X-ray structural methods and of crystal chemistry;
- Fundamentals of diffraction;
- General principles of characterization and interpretation of crystal structures, including the theory of symmetry;
- The thermodynamics of isostructurality, isomorphism, polymorphism, and morphotropy;
- Systematic description of crystals and properties of metals, non-metals, binary and ternary compounds, silicates, coordinate compounds, organic substances;
- The use of concepts from crystal chemistry and X-ray studies to characterize condensed phases with full and partial ordering: liquid crystals and liquids.
The study of crystal chemistry is not limited to crystallographic point and space groups, but has been expanded to include non-crystallographic axes and the symmetry of rods and slices.
A considerable portion of the course is dedicated to organic crystal chemistry and includes the following subjects: symmetry and structural classes of homo- and heteromolecular crystals; theory of close packing of molecules; calculation of the energy of intermolecular interaction in the atom-atom approximation; specific intermolecular contacts and their aggregation (hydrogen bonds, halogen-halogen contacts, and specific contacts involving benzene rings); and revelation of molecular aggregates in organic crystals; the influence of molecular aggregation on the properties of solid and liquid organic substances. The mastering of crystal chemistry requires visualization of structures (with the use of real ball-and-stick models, slides and animation).
Correlations between the structures of liquids and crystals are another basis for generalization of crystal chemistry and the exploration of the interdependence of pharmacokinetical properties of drugs, crystal formation, and molecular aggregation in solution, computer simulation of the structures of solutions, and the interpretation of their melting temperatures, measurement of light scattering and of acoustic speeds in organic liquids and in their mixtures.
One of the most recent studies carried out in the laboratory of crystal chemistry is the refinement of the values of van der Waals radii of organogenic elements on the basis of the statistical treatment of structural data taken from 10000 crystal structures in the CSD.
Contact: Peter M. Zorky, (email@example.com)
High-resolution protein structure at the Institute of Bioorganic Chemistry, RAS, Moscow
The crystal structure determinations (resolution 2.1 Å) of a series of Ca++, Mn++ containing protein - pea lectin in complex with gluco- and mannopyronoside derivatives have revealed the stereochemical features of the binding site responsible for carbohydrate recognition and binding. Based on the determined structure, residue mutations were proposed to change carbohydrate specificity.
The three-dimensional structure (resolution 2.4 Å) of serine protease and bovine duodenase demonstrated the structural features of the active site compatible with effective accommodation of P1 residues typical of trypsin (Arg/Lys) and chymotrypsin (Tyr/Phe) substrates. These specificities in the past were considered to be mutually exclusive. The computer modeling of the complexes with the corresponding octapeptide substrates confirmed the experimental conclusions. The obtained results may permit design of enzymes with a specific ratio of trypsin and chymotrypsin activities.
The crystal structure of the Arg32His mutant of the human tumor necrosis factor (TNF-a), an important immune mediator, has been established at 2.5 Å. Models of the structure complexed with P55 and P75 receptors explained the decrease in its cytotoxic activity. The three dimensional structure of the antigen binding fragment of a monoclonal antibody to human interleukin-2 complexed with antigenic nonapeptide has been determined at 3 Å resolution. Antibody-antigen complexation involves a significant rearrangement of the epitope containing region of the interleukin-2 with retention of the α-helical character of the epitope fragment.
Contact: V.Z. Pletnev, (firstname.lastname@example.org)
Macromolecular crystallography in Pushchino
Subsequently, the activities of the laboratory (see www.impb.ru/lmc for more details) have concentrated on development of new mathematical approaches and software for macromolecular crystallography, and collaboration with different laboratories on macromolecular structures. In particular, the laboratory has facilitated the use of the maximal likelihood principle in macromolecular crystallography (1982), the use of electron density histograms (1986) and the use of mixed (hybrid) electron density models (1984) for phase improvement etc. Most recently the main activity of the laboratory has concentrated on the development of ab-initio phasing methods suitable for low and middle resolution stages of crystallographic studies of macromolecular objects.
Contact: Vladimir Y. Lunin (email@example.com)
Institute of Solid State Physics of the RAS
A variety of crystallographic problems are under investigation.
Crystallography of phase transformations and aperiodic crystals
Another current focus is analysis of aperiodic crystals. The invar effect in incommensurate phases, i.e. the zero-coefficient of thermal broadening in the temperature region of the IC phase has been established. A new type of incommensurate composite structures has been discovered in (Rbx(NH4)(1-x))2SO4 crystals. These composites exhibit incommensurability of host and guest substructures along all three crystallographic directions. To define the structure and properties of such composites, we examine changes in the structures as a function of temperature, pressure and electrical field. A sequence of phase transitions from an incommensurate composite phase into commensurate ones has been detailed and we have shown that the oriented stress causes the phase transition in the host or guest structure.
Contact: V. Shekhtman, I. Shmytko (firstname.lastname@example.org; email@example.com)
Structure analysis of high pressure phases
Contact: Valentina F. Degtyareva (firstname.lastname@example.org)
Structure analysis of low-dimensional organic conductors
Contact: R. Shibaeva, S. Khasanov, L. Zorina (email@example.com)
Amorphous and nanocrystalline systems
Metal-metal and metal-metalloid systems in amorphous and nanocrystalline states are being studied by X-ray diffraction and transmission and high resolution electron microscopy. Samples are produced by controlled crystallization of metallic glasses. Structure stability and evolution have been studied in Fe-, Co-, Ni-, Pd-, Al-, Mg-, Cu-, Zr-based alloys after the decomposition of amorphous alloys prepared by melt quenching. The Al-Ge, Zn-Sb systems were investigated under crystallization of an amorphous phase produced by high pressure with subsequent quenching to liquid nitrogen temperature. The grain size of the nanocrystals is 5-20 nm and the X-ray diffraction pattern contains broadened reflections for small nanocrystals (about 1-5 nm) the X-ray diffraction pattern (Figure below, curve b) is close to that of an amorphous phase (curve a). Both diffraction patterns contain only diffuse maxima, but the curves are different. Curve b corresponds to the structure consisting of both the amorphous phase and nanocrystals with the grain size of 1-5 nm. The high resolution electron microscopy image of this structure is shown in the figure. The structure contains a lot of very small nanocrystals. Analysis of the angular dependence of the diffraction line halfwidth allows us to estimate the main contribution to the broadening and draw conclusions about the fine structure of nanocrystals. All nanocrystals have been found to be defect-free, while Ni nanocrystals contain stacking faults, dislocations, microtwins etc.
X-ray optics of real crystals
X-ray optical diffraction effects under investigation include diffraction focusing of X-ray Bloch waves in perfect single crystals, dynamic diffraction on bent single crystals, waveguide and channeling effects, and X-ray interferometry in a continuous radiation spectrum. Short-wave hard radiation scattering in a short-range field of deformation has been studied, schemes of focusing X-ray optical elements have been proposed, and specific features of diffraction in disordered quasi-crystals have been investigated. A software package has been written to interpret and simulate diffraction images obtained by Laue, Debye and rolling-crystal methods. The phase velocity of hard electromagnetic radiation in a medium is higher than the velocity of light in vacuum. Therefore the effects of both total external and total internal reflections exist for X-ray waves. Experiments on X-ray dynamic diffraction in limited perfect single crystals have been carried out under the conditions of total internal reflection of a scattered wave from a crystal-vacuum interface. The interference pattern, formed by a sum of the primary and mirror-like reflected scattered waves, is extremely sensitive to weak distortions of the crystal lattice. The results obtained open new prospects for diagnostics of defects in single crystals and development of new elements for X-ray optics.
Leonid A. Aslanov
Leonid A. Aslanov was born in St. Petersburg, Russia in 1938 and studied chemistry at Lomonosov Moscow State University. After graduating from the University in 1960 he pursued his interest in crystallography and received his PhD in 1963 based on his studies of the synthesis and crystal structure determinations of ternary sulphides and selenides of alkali earth and some d-transition metals using powder diffraction. He is now employed by the Department of Chemistry of Moscow State University where he started as a junior researcher and is now a full professor.
Between 1965 and 1973 he investigated crystal structures of coordination compounds of rare earth elements and developed, in collaboration with M.A. Poraj-Koshits, a principle for determination of eight-vertexes polyhedra that has had broad application. (J. Struct. Chem. 13, 244 (1972)).
From 1973 to 1987 his research centered on the synthesis and crystal structure determinations of coordination compounds of tin, lead, and antimony and he found, in collaboration with V.S. Petrosyan and O.A. Reutov, a phenomenon of the trans-strengthening of bonds in octahedral complexes of tin and lead which is opposite to trans-effect in transition metal complexes (Zh. Strukt. Khim. 29, 112 (1089)).
From 1979 to 1992 he developed crystal chemical models of atomic interactions (Acta Cryst. B44, 449 and 458 (1988), A45, 661 and 671 (1989), A47, 63 (1991), A48, 281 (1992)). During this period (1981 to 1991) he started an exploration of photocrystallography and together with his collaborators built a specialized four-circle diffractometer (J. Appl. Cryst. 22, 42(1989)), developed software (J. Appl. Cryst. 24, 293 and 910 (1991)) and performed investigations on ferroelectric materials (J. Appl. Cryst. 23, FC1 (1990)). This research was stopped due to lack of financial support in 1992.
Since 1992 he has been doing research in materials science. During the period betwen 1992 and 1998 he proposed, and tested experimentally, an optoacoustic mechanism of latent image formation in silver halide materials (Laser Physics 6,1105 (1996)). Since 1999 he has been studying the crystallization of nanoclusters in ionic liquids.
L.A. Aslanov did postdoctoral research during the 1967-1968 academic year at the University of Sheffield, UK under the supervision of Ronald Mason. He had a Kapitsa Fellowship in 1993 with Judith A.K. Howard at the University of Durham, UK and from 1992 to 2003 he collaborated in the framework of NWO-grants with Henk Shenk at the University of Amsterdam.
L.A. Aslanov is now Vice-President of IUCr, Co-Editor of Acta Crystallographica A, B, C, D, Zeitschrift für Kristallographie and Associate Editor of Crystallography Reviews in addition to activities with other Russian journals and organizations. He has published over 300 papers, 6 books on crystallographic instrumentation, X-ray diffraction, crystal chemistry and another, on ionic liquids, is now in print. He has directed 28 PhD theses.
Hopefully, the articles on 'Crystallography in Russia' presented in this issue of the IUCr Newsletter have begun to provide an accurate picture of crystallography in modern Russia. With these articles, and those to come in the next issue, we will have demonstrated various branches of crystallography: X-ray, synchrotron, neutron instrumentation and methods; development of methods for crystal structure determination based on powder diffraction data; charge density; minerals, small molecules, proteins, aperiodic structures and amorphous materials; crystal growth; crystalline films; high pressure crystallography; Voronoi-Derichlet polyhedra; teaching crystallography and so on and so forth. All comments and remarks should be sent to
L.A. Aslanov, Dept. of Chemistry, Moscow State U., 119992 Moscow, Russia; firstname.lastname@example.org.