Crystalline Substances Research Articles

Anatomical and histochemical evidence of leaf salt glands in Jacquinia armillaris Jacq. (Primulaceae)

Salt glands, which exclude salt solution to avoid tissue toxicity, have been reported for halophytes species of Primulaceae. Jacquinia armillaris is a species of Primulaceae that occurs in saline coastal environments in the Neotropics and possesses peltate trichomes sunken in leaf surface. The present study investigated these trichomes to describe their structure and check if they are true salt glands. Anatomical and histochemical investigation of the secretory trichomes of the leaves of J. armillaris revealed that they comprise a collecting cell and a single stalk cell with multiple secretory cells located on the top. A collecting chamber originates from the distension and release of the cuticle of the secretory cells. A crystalline substance, which tested positive for sodium, was observed in the collecting chamber. This crystalline salt substance is exuded and deposited on leaf surface. Current results demonstrate that the glandular trichomes of J. armillaris are true salt glands, and thus represent a new record of salt glands for the tribe Theophrasteae of Primulaceae s.l.

The study of effectiveness of a high-performance crystal lattice parametric identification algorithm based on CUDA technology

The study of substances with a crystal structure is a complex multi-step process. The key step in the crystalline substance analysis is the unit cell parameter estimation. The estimation of the crystal lattice unit cell parameters is a particular problem that involves the search of the crystal lattice model’s parameters according to the information which can be extracted from the substance. In these recent times, the most accurate information about the substance structure can be obtained with the electron microscope whose linear resolution is high enough to observe the atomic structure of a substance. The problem of parameter estimation in this case means the reconstruction of the three-dimensional crystal lattice with 2-dimentional images received by an electron microscope, and the estimation of the crystal lattice unit cell parameters by reconstructed lattice. In the previous papers the crystal lattice parametric identification algorithms based on solving the local optimization problem were presented. However, the analysis of a large crystal lattice database requires a lot of computations. In this paper, a high-performance crystal lattices parametric identification algorithm using the CUDA technology is proposed. The investigation of the algorithm effectiveness is carried out on the GPU GeForce NVidia GTX 1070 Ti. With data dimension more than 32 translations the acceleration is higher than 70. The algorithm runs more efficiently at the use of a large number of CUDA-blocks.

Alkaline activation of low-reactivity ceramics: Peculiarities induced by the precursors' dual character

In the alkaline activation process, precursors with high reactivity are mostly used. If low-reactivity materials are utilized, it is necessary to take into account their dual character, i.e., that only their amorphous portion can react and the remaining crystalline part acts as microfiller. The composite character of obtained alkali-activated materials can then induce some peculiarities which are not observed for geopolymers based on high-reactivity precursors. In this paper, alkaline activation of low-reactivity ceramic grinding dust is investigated. Microstructure and phase composition of the prepared aluminosilicates are analyzed at first, and empirical geopolymer formulas in the form nM2O∙pCaO∙Al2O3∙xSiO2∙yH2O are derived in dependence on activator alkalinity and curing temperature. The dependence of flexural strength upon Al/(Na+½Ca) molar ratio calculated for the amorphous portion of the analyzed aluminosilicates is identified as the most distinct feature characterizing the links between microstructure, composition, and properties. The improvement of mechanical properties is related to the enhancement of matrix-aggregate composite effect and refinement of pore structure due to the incorporation of crystalline substances into the aluminosilicate matrix.

Noise Power Spectral Density Analysis for Silicon Carbide Substrate MESFET

This paper mainly concentrates on the transistors working functions, electrical characteristics and noise analysis at various operating voltages and temperatures. For this improvement authors are developed simulation methods for better results. The high frequency transistors are exposed with bunch of silicon carbide crystalline substances like 3C, 4H and 6H-SiC MESFETs. Because of the good researchers work, now a day’s all are compared the parameter in between of cubic and hexagonal crystalline structure of silicon carbide MESFETs. Silicon carbide material is having wide band gap because of this reason it’s useful for high energy and high frequency applications. The silicon carbide transistors are having large operating voltage in channel region because of this reason in channel region flows large current and also very less noise is produced. In wide band gap semiconductor transistors are produced very less noise compared to the various categories of substrates.

Synthesis of Polytetrahydrofuran Using Protonated Kaolin as A Solid Acid Catalyst

In this work, a non-toxic protonated kaolin clay exchanged with protons, was successfully applied as a solid acid catalyst for the polymerization of tetrahydrofuran (poly(THF)) at room temperature in the presence of acetic anhydride. Prior to using the kaolin as a catalyst, it was treated with HCl (0.1 M) and characterized using various analytical techniques. The amounts of catalyst and reaction time on the conversion of THF were investigated. Characterizations of nuclear magnetic Resonance of proton (1H-NMR), Fourier Transform Infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), Optical Microscopy (OM), and Differential Scanning Calorimetry (DSC) techniques were used to examine the resulting polymer. X-ray characterization and DSC data indicated that the obtained poly(THF) is a highly crystalline substance. The results showed that protonated kaolin (kaolin–H+) has a high catalytic activity for the polymerization of THF with a conversion rate of 50.02% after 20 hours.

Synthesis of potential antiexudative preparations for 2-((4-amino-5-(furan-2-il)-1,2,4-triazole-(4H)-3-yl)-sulfanyl)-N-acetamide series

Aim. Conduct the purposeful synthesis of new potential biologically active substances of derivatives of 2 - ((4-amino-5- (furan-2-yl) -1,2,4-triazol (4H) -3-yl) -sulfanyl) -N-acetamides and evaluate their anti-exudative activity on the model of formalin edema in rats.Materials and methods. In this work, standard methods of organic synthesis, physical and chemical methods of proofing the structure of synthesized compounds, elemental analysis, 1H NMR spectroscopy, chromatographic mass spectrometry, and antiexudative activity were studied on the model of formalin edema in rats using a digital plethysmometer.Results. By alkylation of 2-((4-amino-5-(furan-2-yl))-4H-1,2,4-triazole-3-thione with N-aryl-substituted α-chloroacetamides in ethanol in an alkaline medium, (4-amino-5-(furan-2-yl)-1,2,4-triazole(4H)-3-yl)-sulfanyl)-N-acetamide. After crystallization we obtained white or light yellow crystalline substances with clear melting temperatures. On the model of formalin edema in rats, the antiexudative activity of the newly synthesized 2-((4-amino-5-(furan-2-yl)-1,2,4-triazole (4H) -3-yl) -sulfanil)-N-acetamides was studied. According to the results of the research, a dependence between "chemical structure – antiexudative activity" of the first synthesized compounds was established. The results of experimental studies showed that fifteen out of twenty one compounds showed anti-exudative activity, eight of which exceeded this activity or were at the reference level of sodium diclofenac.Conclusions. Synthesis of twenty one compounds of 2-((4-amino-5- (furan-2-yl)-1,2,4-triazole(4H)-3-yl)-sulfanyl)-N-acetamide derivatives was carried out and an evaluation of antiexudative activity, the dependence "chemical structure - antiexudative activity" was established. Leading compounds for antiexudative activity were found

Evaluation of Antioxidant Activity of Cinnamic Acid and Some of its Derivatives

Cinnamic acid, chemically known as 3-phenyl-2-propenoic acid is a white-colored crystalline substance which has a broad spectrum of pharmacological actions including antioxidant activity. It is used principally in the flavoring and perfumery industries. The identity, purity, integrity and suitability of the acid were ascertained and established prior to the derivatization reactions. Furthermore, a simple titrimetric method for its assay was designed. The esterification and selective reduction of the acid led to two derivatives coded A2 and S2 whose identities have been established to be ethyl cinnamate and cinnamyl alcohol respectively using the IR spectroscopic technique. Cinnamic acid coded S1 demonstrated a poor antioxidant activity (IC 50 ) of 1.2 µg/mL while A2 and S2 elicited activities of 0.64 µg/mL (moderate) and 0.84 µg/mL (marginal) respectively. The obtained results indicate that esterification enhances the antioxidant activity of cinnamic acid.

Mathematical Modeling of the Process of Centrifugal Washing of Sludge

In the chemical, food and other industries, in many cases it is necessary to clean crystalline powdery substances to remove surface impurities. For this, at the final stage of the treatment process, they are washed with water or other liquids. In this article, this process is investigated on the example of quantitative analysis of the dissolution of sodium chloride crystals in water by pressure filtration of the solution through the sludge of the processed product on the basis of filtration on centrifugal equipment. To this end, a physico-mathematical problem of the flow of substances in the interstitial capillary gap is formulated in terms of molecular mass by modeling a cylindrical channel. Based on the proposed model and operating parameters of the process of washing NaCl crystals with water from sludge on a centrifugal machine, numerical analysis of the process simulating cleaning the surface of this product to remove impurities was carried out.

The Search for Biologically Active Compounds in the Series of N-ethoxyethylpiperidine Derivatives

With the aim to introduce fragment of cyclopropane and fragments of p-, m-, o-fluorophenyls into the structures of N-ethoxyethylpiperidines, acylation of oxime and phenylacetylenic alcohol of 1-(2-ethoxyethyl)-4-ketopiperidine by cyclopropanecarbonylchloride was carried out; on the basis of 1-(2-ethoxyethyl)-4-ethynyl-4-hydroxypiperidine (cascaine alcohol), acylation by 4-fluoro-, 3-fluoro-, 2-fluorobenzoylchlorides was carried out with formation of the corresponding piperidine containing hydrochlorides of cyclopropanecarboxylic acid esters and para-, meta-, ortho-fluorobenzoic esters. Acylation reaction on the hydroxyl group of compounds is carried out in absolute dioxane, the acylating agents are cyclopropanecarbonylchloride, p-, m-, o-fluorobenzoyl chlorides taken in excess. The obtained esters of cyclopropanecarboxylic and para-, meta-, ortho-fluorobenzoic acids are crystalline substances with a clear melting point, well soluble in water, ethanol, acetone. P-fluorobenzoates are obtained with better yields, m-fluorobenzoates occupy an intermediate position, and o-fluorobenzoates are formed with the lowest yields. The best yields of fluorobenzoates are obtained using dioxane as a solvent. Para-, meta-, ortho-fluorobenzoic esters of 1-(2-ethoxyethyl)-4-ethynyl-4-hydroxypiperidine coded A-4 – A-6 were studied for the presence of antimicrobial activity, the actions of these preparations were evaluated in vitro in relation to strains of gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, gram-negative strains of Escheriсhia coli, Pseudomonas aeruginosa and to yeast fungus Сandida albicans by the diffusion method into agar (holes). Introduction of fluorine atom into the structure of cascaine lead to manifestation of antimicrobial activity.

The effect of the Sequoiadendron giganteum (Lindl.) Buchholz cone crystals on germination

The cones of the giant sequoia contain red, water-soluble crystalline substances known as cone crystals. The inhibitory effect of this extracted material on Norway spruce, Scots pine and European larch germination was newly examined. Sown seed representative samples without and with added cone crystals were compared after their incubation in the same appropriate conditions. All these cases have brought compelling evidence that cone crystals totally inhibit germination. However, the chemically inhibited seeds being rinsed afterwards germinated very well. This switch effect caused by the cone crystals of the three above-mentioned conifers proved to be a nonspecific tool. Seeds of the giant sequoia, naturally affected by the cone crystals, were sown as rinsed and non-rinsed samples. Both the samples, grown on a wet peat substrate in appropriate conditions for 16 weeks, exhibited an equal, yet very low viability of 1.3% at the same time. This low number, fixed in seeds of the tree being far from the ecological optimum, does not allow any disputation with other authors.

Hydrolysis and condensation of ZIF-8 in water

Recent studies have shown that zeolitic imidazolate framework-8 (ZIF-8) crystallites are not stable in aqueous solution under ambient conditions. When immersed in water, ZIF-8 crystallites are hydrolyzed to zinc and imidazolate ions, which can be condensed to form a new solid substance upon removal of water by evaporation. The present work demonstrates such ZIF-8 phase shift substance is of crystalline structure but does not belong to any known (pseudo)polymorphs of ZIF-8, ZIF-L, dia(Zn), or decomposed product of ZIF-8: Zn(OH) 2 and 2-methylimidazole. FTIR characterization shows the co-existence of Zn–O and Zn–N bond in the new substance, confirming the partial cleavage of Zn–N bond in ZIF-8 building unit in the hydrolysis step. EDS quantification for the ZIF-8 phase shift substance gives a C:N:Zn:O atomic ratio of 40:20:5:4. Based on EDS and FTIR results, the chemical formula of Zn 5 (HMIM) 4 (MIM) 6 (OH) 4 for the building unit of such substance is proposed consisting of four partially hydrolyzed and one undisturbed secondary ZIF-8 building units. The ZIF-8 phase shift substance is crystalline with a nearly identical atomic composition as ZIF-8 (except for increased oxygen content), suggesting it might be a novel pseudo-polymorph of ZIF-8. The hydrolysis and condensation of ZIF-8 can be described by a mechanism that includes (1) hydrolysis of ZIF-8 through cleavage of Zn–N bond to form zinc and imidazolate ions and partially hydrolyzed ZIF-8 units and (2) condensation of these ions and clusters with the help of hydrogen bond to form the new structure of ZIF-8 phase shift substance. • Hydrolysis of ZIF-8 in water proceeds via partial cleavage of Zn–N bonds. • Hydrolysis and condensation of ZIF-8 leads to a new crystalline substance with same composition as ZIF-8. • Improved stability of ZIF-8 can be achieved by protecting Zn–N coordination bond from water attack.

Solvent-free Methods for Co-crystal Synthesis: A Review.

Pharmaceutical co-crystals are the homogeneous crystalline substances composed of two or more substances bound together in the same crystal lattice via noncovalent interactions like hydrogenbonding, electrostatic interaction and Vander Waals interactions. Currently, co-crystals provide excellent opportunities to the formulation scientists in developing new pharmaceutical products by improving the pharmaceutically significant properties like solubility, dissolution rate, bioavailability, stability, and some other derived properties. Due to their ability to improve pharmacokinetic performance and their important intellectual property status, co-crystals are likely to have a very significant role in future drug development. Thus, formulation scientists have their focus on the development aspects of a co-crystallization process that include a rational selection of co-former, the discovery of novel synthetic procedures and new characterization techniques, and large scale production of these novel materials. The objective of this article is to present an extensive review of solvent-free methods for co-crystal synthesis, mainly focusing on the principle mechanisms, advantages, and drawbacks of each method. From the review of the topic, it is clear that the solvent-free methods can offer numerous advantages over solvent-based methods in the design and the production of co-crystals of pharmaceutical use and these methodologies can also pave the path to advancing the field of co-crystal synthesis. Some of the advantages accompanied with solvent-free methods are the use of no or very less amount of solvent(s), exceptional purity and quality of produced co-crystal, large scale production and the short reaction times in few cases.

Performance and Membrane Fouling Properties in an Anaerobic Membrane Bioreactor for Salty Wastewater

In the research, an anaerobic membrane bioreactor (AnMBR) was used to treat simulated salty organic wastewater, and the effect of salinity on reactor performance and membrane fouling properties was investigated. The results indicated that when the influent salinity increased gradually but was lower than 9.1 g·L-1, the reactor ran stably and the effluent performance was good. When the salinity increased to 10 g·L-1, the COD removal-efficiency, gas production, and methane content decreased significantly; meanwhile, the sludge concentration, sludge volume index (SVI), soluble microbial products (SMP), and extracellular polymeric substance (EPS) levels became elevated at first and then declined with the rising salinity. The system developed compact flocs and a high settling ability. The hollow fiber membrane module was run for three cycles in 118 d. The membrane operating cycle was extended from 31 d to 48 d with the increasing salinity, which favored the control of membrane fouling. SEM-EDX analysis results revealed that there were similar crystalline substances in the film membrane foulants, and Na, Mg, Al, Si, Cl, K, Ca, and Fe were the main inorganic elements. Excitation emission matrix (EEM) analysis results demonstrated that proteins and humic acids were the main components of the organic membrane foulants.

Possibilities of Neural Network Powder Diffraction Analysis Crystal Structure of Chemical Compounds

Some possibilities of using convolutional artificial neural networks (ANN) for powder diffraction structural analysis of crystalline substances have been investigated. First, ANNs are used to classify crystalline systems and space groups according to calculated full-profile diffractograms calculated from the crystal structures of the ICSD database (2017 year). The ICSD database contains 192004 structures, of which 80% was used for in-depth network training, and 20% for independent testing of recognition accuracy. The accuracy of classification by a network of crystalline systems was 87.9%, and that of space groups was 77.2%. Secondly, the ANN is used for a similar classification of structural models generated by the stochastic genetic algorithm in the search processes for triclinic crystal structures of test compound K4SnO4 according to their full-profile diffraction patterns. The classification criterion was the entry of one or several atoms into their crystallographic positions in the structure of a substance. Independent deep network training was performed on 120 thousand structural models of the K4PbO4 triclinic structure generated in several runs of the genetic algorithm. The accuracy of the classification of K4SnO4 structural models exceeded 50%. The results show that deeply trained convolutional ANNs can be effective for classifying crystal structures according to the structural characteristics of their powder diffraction patterns

Electrospray Film Deposition for Solvent-Elimination Infrared Spectroscopy.

The application of electrospray (ES) for quantitative transfer of analytes from solution to an internal reflection element for analysis by attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy has been developed in this work. The ES ATR FT-IR method is evaluated with non-volatile and semi-volatile organic and inorganic compounds dissolved in pure organic solvents or organics in a mixture with water. The technique demonstrates the capability for rapid solvent evaporation from dilute solutions, facilitating the creation of thin films that allow ATR FT-IR to generate transmission-mode-like spectra. Electrospray ATR FT-IR with multiple reflections displays a linear response ( R2 = 0.95-0.99) in absorbance with the deposited mass and instrumental detection limit < 100 ng, which demonstrates potential for quantitative applications. The method is applicable when crystalline substances are present, even though the formation of particles restricts the upper limit of mass loadings relative to substances forming homogeneous films. In addition to the solvent, semi-volatile compounds can evaporate during the ES process; the magnitude of losses will depend on solution composition and temperature.

Isolation and characterization of lupeol from the whole plant of &lt;i&gt;Phaulopsis bateri&lt;/i&gt;

This work was aimed at isolating and characterizing the bioactive constituents from the crude methanol extract of the whole plant of Phaulopsis barteri . The crude extract which was subjected to a silica gel column chromatography separation using petroleum ether/ethyl acetate blend, eluted a white crystalline substance with a melting point of 215-216 0 C. PBA shows recognizable peak at 79.02ppm which is characteristic of a carbon carrying an oxygen and the 1 HNMR spectrum which shows an olefinic proton at δ 4.71 and 4.56 respectively was identified as lupeol which is a C 30 H 50 O moiety. Identification of the compound was purely by spectral analysis. Keywords: Phaulopsis barteri , Lupeol, C 30 H 50 O, Chromatography

Prediction of heat capacity for crystalline substances

An algorithm is derived that estimates the trend of heat capacity with temperature based on zero-Kelvin properties (V0,B0), the Debye temperature and the thermal expansion coefficient at the Debye temperature. The algorithm predicts not only the trend of heat capacity but also the temperature trend of the volume and the bulk modulus, which can be also included in new thermodynamic databases. Calculations of thermophysical properties take less then two minutes on a standard desktop CPU for a temperature range between 0 K and 2000 K. The algorithm is used to assess thermophysical properties of the intermetallic phases η (Fe2Al5), ϵ (Fe5Al8) and τ4 (FeAl3Si2) in comparison to calculated DFT results and experimental data. A method is shown how the melting point of a substance can be predicted using our algorithm in combination with low temperature cp and volume data.

CONCERNING TO REMOVAL METHODS HYDRATE FORMATION (ON EXAMPLE OF URENGOY FIELD)

Background At present, the development of gas fields is in most cases complicated by the increase in moisture content in natural gas. The main reason for this phenomenon is a decrease in pressure, gas temperature and, as a result, this leads to the appearance of water vapor that has condensed and accumulated in wells and gas pipelines. Further saturation of natural gas at an elevated pressure and positive temperature can lead to the formation of solid physicochemical compounds - hydrates. The occurrence of such crystalline substances can lead to the blockage of wells, gas pipelines, separators, disruption of the work of stabilizing and gauging devices, and as a result to a decrease in the level of oil production. Often, pressure regulators and fittings fail, gas is throttled, accompanied by a sharp decrease in temperature, and the disruption of the normal operation of the oil and gas production equipment. Aims and Objectives Determination of factors affecting the intensity of hydrate formation, and the study of methods to combat the formation of gas hydrates on the example of the Urengoy field. Results The factors that directly affect the intensity of hydrate formation are determined: moisture content, temperature, pressure, component composition of the gas. The possible places for gas hydrates formation are given: at fittings, in piping of pipes, in separators, in loops, on diafragms of metering sections. The main methods of preventing the hydrate formation and removal of hydrate plugs are present: increasing the gas temperature, reducing the gas pressure, removing moisture from the gas using absorbents and adsorbents, inhibitors. Methods for the control of hydrate formation, using in Urengoi field, are presented. A thermal calculation of the plume was performed, which allows determining the temperature change along the gas pipelines and determining the possible place of hydrate formation.

Integrated instrumentation for combined laser-induced breakdown and Raman spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is capable of providing elemental analysis while Raman spectroscopy is powerful for molecular and structural characteristics of crystalline substances. This work proposes an innovative hybridized instrument to simultaneously obtain molecular and elemental information on an analyte. The instrument was designed in a compact form due to the integration of a modularized structure and a single unified control system, which was ultimately restricted to a size of 420 mm × 520 mm × 650 mm, suitable for field applications. An orthogonal optical system was used to focus the laser beams and obtain the spectra and real-time imaging of the tested area. A pulsed laser (1064 nm, 100 mJ, 1–20 Hz) and a continuous-wave laser (532 nm, 22 mW) were applied for LIBS and Raman measurements, respectively. The multichannel original equipment manufactured spectrometer ensures a wide spectral range (185–850 nm for LIBS and 400–4000 cm−1 for Raman) on the basis of its low weight. A central control circuit board was specially developed by integrating the control command and data transmission to achieve centralized control of the components, thereby providing precise timing control and improving the instrument. The enclosed sample chamber had the function of mapping and shielding the fill gas. The developed client software provided a comprehensive operation interface. Ammonium persulfate and carbonate were used to demonstrate the feasibility of the developed hybrid instrument to obtain the element and molecular structural information of analytes.

The Criterion for Choosing an Insulator for Sili-con MOS Structures

Nowadays, MIS structures based on silicon dioxide films have become the most widely used. However, the desire to reduce the channel length and the nano-scaling in electronics showed, that SiO 2 can’t provide the specified MIS devices parameters and characteristics. This is due to the superfine insulator films problem. First of all, this can be solved by replacing SiO 2 with another insulator that meets certain requirements. Oxides of transition and rare-earth metals meets almost all of these requirements. However, the principle issue of insulator and semiconductor compatibility remains unsolved in terms of ensure theirs interface quality. Therefore, the researching purpose is to create a general approach to the selection of insulator which is an alternative to silicon dioxide. This insulator must provide a high quality of insulator-semiconductor interface. In MIS structures, the main indicator of semiconductor-insulator interface is its density of the electric charge. Low values of the charge density at the semiconductor-insulator interface are corresponds to high quality of the interface. This is due to the fact that low interface charge density has low affecting on threshold voltage and provide higher its stability. In the first approximation, the surface states density is identically equal to the incomplete bonds density at semiconductor-insulator interface. Therefore, this parameter is selected as the basis of the insulator choosing criterion for a particular semiconductor substrate. It is shown that the classical theory of crystalline lattice (site aspect) can't allow to obtain an analytical expression for the insulator choosing criterion for MIS structures. Therefore, a new form of description of a crystal lattice (intersite aspect) is proposed. Since the crystals differs not only by symmetry but also by the crystallographic orientation of their interface with the vacuum, then an infinite number of solutions about value of incomplete bonds density at the interface correspond to each pair of materials. For obtaining only the one solution by using insulator choosing criterion, a new characteristic parameter of the crystalline substance is introduced - the average bond length. To confirm the practical significance of the average bond length, the relationship between this parameter and electron work function is obtained. The experiment based on literary data of both electron work function and lattice constants was made. The experimental results proves both validity of the relationship and practical significance of the average bond length. On the basis of the intersite aspect and the average bond length, general insulator choosing criterion for MIS structures on certain semiconductor substrate was obtained. For replacement of silicon dioxide in silicon MIS devices, insulator was selected from suitable materials namely oxides of transition and rare-earth metals. The incomplete bonds density at the insulator-silicon interface was calculated for each of these materials. Analysis of the calculation results showed that, in accordance with the insulator choosing criterion, the most promising material is CeO 2 . The insulator choosing criterion for MIS structures on certain semiconductor substrate is proposed. Its allows, under other equal conditions, to choose the suitable insulator which will provide the least electric charge density at the insulator-semiconductor interface, in comparison with other pretenders. In case of a silicon substrate, such insulator is CeO 2 . A new characteristic parameter of a crystalline materials is introduced - the average bond length. The analytical expression, which get the relationship between this parameter and the electron work function, is obtained. The obtained results provide an opportunity to make choices insulator for MIS devices based on not only silicon substrates, but also any other semiconductor materials. The proposed insulator choosing criterion can serve as the basis for build new criteria. This ones can help in solving more complicated problems like choosing insulator for MIS devices based on semiconductor substrate with a certain crystallographic orientation. Bibl. 10, Fig. 9.