The Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences (hereinafter referred to as RAS) was founded in 1988 on the basis of the Department of Special-Purity Substances and Volatile Metal Compounds of the Institute of Chemistry of the USSR Academy of Sciences. The founder and the first Director of the Institute was Grigory Grygorievich Devyatykh (1918 – 2005), Academician of RAS, Hero of Socialist Labor, Laureate of Lenin prize and the Prize of the Russian Federation Government.

The setting up of the Institute as an academic institution was the natural result of the success of Nizhny Novgorod school in the development and analysis of high-purity substances. Investigations on this scientific issue were started by G.G. Devyatykh in 1956 at the Chemical Faculty of N.I. Lobachevsky Gorky State University. Up to 1963 the work was carried out by the Department of Inorganic Chemistry and the Laboratory of Mixture Separation of the Research Chemistry Institute at Gorky State University. From 1964 this research area started to develop at the Laboratory of Polymer Stabilization of the USSR Academy of Sciences. In 1968 the laboratory turned into the Institute of Chemistry of the USSR Academy of Sciences.

Founder of the IChHPS of RAS
G.G. Devyatykh, Academician

Since 1988 the Institute of Chemistry of High-Purity Substances of the USSR Academy of Sciences (hereinafter referred to as RAS) has become the research center of the production and analysis of high-purity substances and materials in Gorky (later in Nizhny Novgorod).

High-purity substances are the basis of many sections of material science. They are used to manufacture materials required for the fields of industry of high technology. Micro- and nano-electronics, fiber and power optics, opto-electronics are an incomplete list of the fields whose very existence is due to substances and materials produced in high-purity state.

The history of Nizhny Novgorod scientific school on the chemistry of high-purity substances, the largest in our country has existed for half century and has always been associated with the life and creative research of its establisher Academician Grigory Grigorievich Devyatykh, who is one of greatest chemistry scholars in this country. The notion of «chemistry of high-purity substances» itself was introduced by G.G. Devyatykh.

The academic school of G.G. Devyatykh launched many eminent scientists on chemistry of high-purity substances and materials with their own fields of investigation. Among them are M.F. Churbanov, Academician of RAS, Director of the IChHPS of RAS since 1998; A.N. Guriyanov, Corresponding Member of RAS, Dr. Sc. (Chem.); A.V. Gusev, Dr. Sc. (Chem.); V.A. Krylov, Dr. Sc. (Chem.); I.D. Kovalev, Dr. Sc. (Chem.); A.N. Moiseev, Dr. Sc. (Chem.); E.M. Gavrishchuk and many others.

Further follows the synopsis of the major contributions of IChHPS of RAS to the fundamentals of high-purity substances chemistry.

Development of the scientific fundamentals for the processes of mixture separation and production of high-purity substances. Development of ultrapurification methods for substances of different chemical groups

The physical and chemical fundamentals have been developed for the production of high-purity substances of different chemical groups. Statistical and thermodynamic techniques have been suggested to calculate the separation factor for liquid-vapor and crystal-liquid equilibria making it possible to theoretically estimate the value of the separation factor. Theoretical fundamentals have been developed for ultrapurification of substances in counter-flow multi-stage processes, i.e., rectification, counter-flow crystallization from the melt, zone recrystallization.
Scientific fundamentals have been formulated for the processes of ultrapurification; volatile inorganic hydrides, chlorides, organo-metallic compounds, simple substances have been produced in high-purity state. Many of them have a record-breaking degree of purity.

The original designs of columns were developed and their efficiency has been manifested in ultrapurification of specific substances.
A large volume of work has been done in the investigation of the contaminating effect of structural materials during their contact with high-purity substances. The mechanism of this process was investigated, the income rate of impurities into volatile inorganic chlorides from most widely used structural materials has been determined. This provides purposeful selection of materials while developing the apparatus for production of high-purity substances in view of the required purity of the target product. The contaminating effect of the apparatus material has been proved as a phenomenon which fundamentally limits the attainable degree of the purification of substances.

The behavior of suspended nano-particles as a specific group of impurities has been studied during ultrapurification of volatile substances. It has been found as drastically different from the behavior of impurities forming a true solution with the purified substance. A new highly efficient method has been suggested and implemented for ultrapurification from suspended particles, i.e., film rectification with vapor superposition of temperature gradient (thermal distillation).

Development of methods for analysis of high-purity substances

The work on the production of high-purity substances was accompanied by the simultaneous or advanced development of the quantitative and qualitative determination of impurities. High-sensitive techniques of analysis were developed based on source and laser mass spectrometry, photoelectric spectroscopy, chemical atomic-emission and atomic absorption analysis, electron microscopy, X-ray microanalysis, IR- and UV-spectroscopy, gas and liquid chromatography, laser ultramicroscopy. It made it possible to thoroughly characterize the impurity composition of high-purity substances and materials of different chemical groups. Actually all the major impurities can be determined in solids with concentration up to 10-10 %; the impurities in elemental and molecular form in volatile substances from 10-1 % to 10-8 %.

Production, analysis and investigation of the properties of high-purity substances. Development of new materials based on high-purity substances

A great amount of work was conducted on the investigation of the properties of high-purity substances. Explosion and fire hazards of volatile hydrides and organo-metallic compounds were investigated. Heat capacity and heat conductivity were measured for a number of high-purity substances as well as the electrical conduction of metals in the low-temperature region; the effect of impurities upon these properties was investigated.
Scientific fundamentals and methods of production were developed for a number of high-purity optical and semiconductor materials, including quartz glass for optical fibers with ultimately low optical losses, polycrystalline zinc selenide and zinc sulfide for power optics of the middle IR-range, chalcogenide glasses for production of optical fibers with low optical losses in the middle IR-range, single-crystal germanium for detectors of ionizing radiation. Jointly with OFSC of RAS the methods of production were developed and the quartz optical fibers were fabricated with ultimately low (0.2 dB/km) optical losses for fiber optic communication lines as well as the chalcogenide optical fibers with record-breaking low optical losses in the middle IR-range for the present time (10-100 dB/km). The impurity-sensitive optical properties (optical losses, radiation resistance) of high-purity quartz glass, chalcogenide and fluoride glasses, polycrystalline zinc selenide and zinc sulfide were investigated.

Development of scientific foundations for the technology of high-purity substances materials and functional units on their basis
The results of the accomplished investigations were presented in over 1700 scientific papers, in monographs, in ~200 patents and certificates of authorship on inventions. Investigations on the basic problems in the chemistry of high-purity substances are accompanied with the development of rational schemes, methods and techniques for the production and analysis of high-purity substances, the corresponding apparatus, the production of pilot lots of these substances and materials. This approach provides a reliable check of the results of scientific investigations, a prompt transition from high-purity substance to a high-purity material, the testing of materials in different practical applications. The results of a number of achievements were applied in industry.
From the start of the work on the problem of high-purity substances Academician G.G. Devyatykh put in a lot of attention and effort to consolidate the work of all teams in this country occupied with this problem. Consequently, from the start of the work on high-purity substances, the Gorky city turned to be the permanent place of All-Union (and then All-Russian) conferences on the chemistry of high-purity substances and materials, the first of which was held in 1961.

The open exchange of information and the joint investigations made it possible to realize a unique scientific project of collecting and attesting of samples of the purest substances and materials produced both in Russia and abroad. The project was implemented within the framework of the Permanent Collection Exhibition of Special-Purity Substances set up by the decision of the Presidium of the USSR Academy of Sciences in 1974 with the goal of getting objective information on the state of the problem of high-purity substances. During the period of work of 35 years a unique collection of high-purity substances has been acquired including more than 600 samples; their impurity content was investigated and the information-calculation system «High-Purity Substances and Materials» was created comprising the data base of ~ 42000 impurity-determinations. According to the data of the Collection Exhibition among the purest samples of chemical elements only 4% has the total content of impurities at the level of 10-6 at. % and, approximately, in one-third of chemical elements the total content of impurities is close to 10-3 at. %. The absolute content of impurities even in the purest solids is 1015-1016 at./cm3. This level of impurities does not preclude the effect of impurities upon substance properties. It is known that impurities and structural defects contribute greatly to the quantitative value of the investigated properties. The increase of the degree of purity serves to attain a state when the defect contribution to the investigated property will be equal to the value of impurity contribution. The lower boundary of impurity sensitivity characteristic of the «property of high-purity substance – impurity content» dependence corresponds to this content of impurities. Determination of these values for all impurity-sensitive properties is the main subject of the chemistry of high-purity substances. The main direction of the investigations at the IChHPS of RAS is advancing to a higher level of purity both in the currently purest substances and in less pure substances. Production of purer substances can lead to the detection of new properties or to distinct manifestation of the known properties of substances.