Gadolinium oxotellurites GdMeTeO4.5 (Me – Mg, Ca) were synthesized using ceramic technology with solidphase interaction of oxides Gd2O3 and TeO2 with carbonates MgCO3 and CaCO3. X-ray characteristics were obtained using an Empyrean powder diffractometer and specialized programs Data Collector version 7.7h and X’Pert HighScore Plus using the Crystallography Open Database and PDF-2. Based on X-ray studies, it was established that the synthesized tellurites crystallize in a tetragonal syngony. The reliability and correctness of the indexing results is confirmed by the satisfactory agreement between the experimental and calculated parameters of the crystal lattice, unit cell volumes, X-ray and pycnometric densities. A study of the temperature dependence of the electrical resistance of gadolinium-magnesium tellurite has established that the compound may have semiconductor properties, with a band gap ∆E = 2.64 ± 0.13 ∙ 10–2 eV. The results can be used for the synthesis and study of new derivatives of tellurium and rare earth elements and are of interest for electronic technology. X-ray characteristics of new tellurites of s-, f-elements are the starting materials for inclusion in fundamental data banks and reference books.

By the method of dynamic calorimetry in the range of 298.15-673 K, the heat capacity of titanium-manganite LaСаTiMnO6, obtained by solid-phase interaction at 800-1200oC from lanthanum, titanium (II), manganese (III) and calcium carbonate oxides was studied. On the dependence curve Ср°~¦(T) in the specified temperature range, a λ-shaped effect was detected at 598 K, probably related to the phase transition of the second kind. A fundamental constant is determined — the standard heat capacity of LaСаTiMnO6, equal to 221±14 J /(mol×K). Its standard entropy, equal to 206±6 J/(mol×K), was estimated by the approximate method of ion increments. Based on experimental data, taking into account the temperature of the phase transition, the equations describing the temperature dependences of Ср°~¦(T) and the thermodynamic functions So (T), Ho (T) — Ho (298.15) and Фхх(Т) of the investigated titanium-manganite lanthanum and calcium are calculated. The standard heat capacity of LaСаTiMnO6 is also calculated using the Debye method, the value of which is in good agreement with experimental data. According to the developed methodology, the standard enthalpy of titanium-manganite formation was calculated, equal to — 3867.5 kJ/mol.

We study the temperature dependences of the specific heat of nanostructured lanthanum and sodium copper–zinc manganite LaNa 2 CuZnMnO 6 by dynamic calorimetry in the temperature range 298.15–673 K. The curve of specific heat dependence on temperature at 348 K shows a jump, probably related to a phase transition of the second kind. We derive the equations for the temperature dependence of specific heat, taking the phase transition temperature into account. The standard entropy is calculated, and the temperature dependences of the thermodynamic functions of the studied manganite are determined. The temperature dependence of the electrical resistance is studied in the range of 293 to 483 K using an LCR meter (Taiwan); at 343 K, the possible semiconductor conductivity transforms into a metallic one; and at 443 K, the metallic conductivity transforms into a semiconductor one. The bandgaps are calculated.

The titanium-manganites of LaMeI2TiMnO6 (MeI — Li, Na, K) were synthesized by the ceramic technology with the high-temperature reaction of oxides of La2O3, TiO2, Mn2O3 with carbonates of Li2CO3, Na2CO3, K2CO3 within 800–1200 ºС. The X-ray diffraction methods demonstrated that all of them were crystallized in the cubic syngony with the lattice parameters such as LaLi2TiMnO6 — а = 13.480.02 Å, Vo = 2449.460.06 Å3, Z = 4, Voel.cell = 612.870.02 Å3, roent. = 3.81; pick. = 3.780.03 g/cm3; LaNa2TiMnO6 — а = 14.060.02 Å, Vo = 2779.430,06 Å3, Z = 4, Voel.cell = 694.960.02 Å3, roent. = 3.67; pick. = 3.650.01 g/cm3; LaK2TiMnO6 — а = 14.740.02 Å, Vo = 3202.520.06 Å3, Z = 4, Voel.cell = 800.520.02 Å3, roent. = 3.45;  pick. = 3.430.01 g/cm3. Correctness and authenticity of the results on the indexing of X-ray photographs of titanium-manganite were confirmed with the good experimental and calculated values (104/d2), the pycnomet-ric and X-ray densities, and also the theoretical and experimental values of cell volumes. The rising of values of the lattice parameters of the synthesized titanium-manganites was determined with increasing in the ionic radii from Li to K.

Copper–zinc lanthanum and calcium manganite LaCaCuZnMnO 6 was synthesized from oxides of lanthanum(III), copper(II), zinc(II), manganese(III), and calcium carbonate in the temperature range 1073–1473 K. Nanostructured particles were obtained by grinding the material in a vibratory mill. The heat capacity of the compound was studied in the range of 298.15–673 K on an IT-S-400 calorimeter. On dependence curve C_p^∘ f ( T ) at 598 K, an anomalous jump in heat capacity was detected. The temperature dependences of the electrical resistance and relative permittivity were studied on an LCR-781 setup (Taiwan) at 293–483 K and at frequencies of 1, 5, and 10 kHz. A semiconductor character of the conductivity was established. At 483 K, an anomalously high value of the permittivity was revealed at all studied frequencies.

The work is devoted to the synthesis of graphene-containing nanomaterials by the method of electric arc discharge from coal products and the study of the physicochemical properties of the obtained samples.

The copper-zinc manganites of LaMeIICuZnMnO6 (MeII — Mg, Ca, Sr, Ba) have been synthesized with the high-temperature interaction of alkaline earth metals carbonates with oxides of lanthanum (III), copper (II), zinc (II) and manganese (III). The synthesized polycrystalline copper-zinc manganites have been grinded on the Retsch vibration mill MM301 (Germany). As a result their nanostructured particles have been obtained. Their sizes have been determined using an electron microscope Mira3 LMU, Tescan. Methods of radiography determined that all synthesized nanostructured copper-zinc manganites crystallize in the cubic syngony with the following parameters of a lattice: LaMgCuZnMnO6 — а = 13.530.02 Å, Vo = 2476.810.06 Å3, Z = 4, Voelect.cell = 619.200.02 Å3, roent = 4.52; pick = 4.500.01 g/cm3; LaCaCuZnMnO6 — а = 13.690.02 Å, Vo = 2565.730.06 Å3, Z = 4, Voelect.cell. = 641.430.02 Å3, roent = 4.43; pick = 4.410.01 g/cm3; LaSrCuZnMnO6 — а = 13.910.02 Å, Vo = 2691.420.06 Å3, Z = 4, Voelect.cell = 672.850.02 Å3, roent = 4.99; pick. = 4.960.01 g/cm3; LaBaCuZnMnO6 — а = 14.550.02 Å, Vo = 3080.270.06 Å3, Z = 4, Voelect.cell = 770.070.02 Å3, roent = 4.95; pick = 4.940.01 g/cm3. The X-ray investigations demonstrated that the values of lattice parameters of the studied copper-zinc manganites have been increased from Mg to Ba. As a result of the investigations, these compounds can be included in Pm3m spatial group.

The synthesis of graphene-containing nanomaterials from grade D coal of the Shubarkol deposits (Kazakhstan) was carried out. The graphene-containing nanomaterials were prepared using electric arc discharge based on coke from Shubarkol coal obtained at 1173 K in an atmosphere of nitrogen. Several layered graphene flakes were synthesized using an arc discharge at a constant voltage of 75 V and current strengths of 150 and 300 A in a quartz reactor. The physicochemical characteristics and surface morphology of the test samples were studied. The electrical resistance ( R ), capacitance ( C ), and dielectric constant (ε) of the graphene-containing material were determined in a temperature range of 293–483 K.

The paper demonstrates the results of the experimental investigation of the thermodynamic and electrophysical properties of the new nanostructured copper-zinc manganite of lanthanum and lithium (LaLi2CuZnMnO6).

The chemical analysis of humic acids and their activated forms based on brown coal from the Maikuben coal basin (Kazakhstan) was carried out. The humic acids were obtained on the basis of potassium humates. Activated humic acids (AHAs) were prepared by carbonization and activation in argon and water vapor atmospheres at 873 K, and the physicochemical characteristics and surface morphology of the test samples were studied. The electrical resistance ( R ), electric capacitance ( C ), and dielectric constant (ε) of the samples in a temperature range of 293–483 K were determined for the first time. The samples obtained were tested as an adsorbent for water treatment in order to remove heavy metals.

The temperature dependences of the specific heat of nanoscale (nanocluster) cobaltite(nickelite)-cuprate-manganites LaSrCoCuMnO6 and LaSrNiCuMnO6 have been studied via experimental dynamic calorimetry in the range of 298.15–673 K. The temperature dependences of the specific heat $${C}_{p}^{\circ }$$ ~ f(T) of LaSrCoCuMnO6 (at 323 and 523 K) and LaSrNiCuMnO6 (at 348 K) exhibit anomalous jumps in the specific heat, which are likely due to the second-order phase transitions. Based on the experimental data on $${C}_{p}^{\circ }$$(T) and the calculated value of entropy S°(298.15), the temperature dependences of the specific heat and thermodynamic functions of the studied compounds are calculated in the temperature range of 298.15–673 K.

The chemical composition and the temperature dependences of the electrical characteristics (electric capacity, electrical resistance, and dielectric constant) of the ash of Bogatyr coal in its original form and after electromagnetic and electric discharge treatments in a range of 293–483 K were studied, and the procedures of these coal ash treatments were specified. Temperature ranges in which the materials exhibited semiconductor properties and metallic conductivity were determined. The band gaps (Δ E ) were calculated for the test samples. The results of measurements showed that the ash after electric discharge treatment has the highest values of electric capacity and permittivity and the lowest electrical resistance, as compared with those of the initial ash and ash after electromagnetic treatment. Coal ash after electric discharge treatment seems a promising prepared raw material for its further thermochemical processing with the extraction of valuable components such as rare metals, silica, and alumina.

The temperature dependences of the specific heat capacities of nanosized samples of lanthanum magnesium cobaltite cuprate manganite LaMgCoCuMnO6 and lanthanum magnesium nickelite cuprate manganite LaMgNiCuMnO6 are studied via calorimetry in the temperature range of 298.15–673 K. Curve $$C_{p}^{ \circ }$$(T) shows that LaMgCoCuMnO6 and LaMgNiCuMnO6 undergo second-order phase transitions at 398 and 523 K, respectively. The standard specific heat capacities of the above compounds are calculated with independent means based on characteristic Debye temperatures determined via the Koref and Nernst–Lindemann equations. Their values agree satisfactorily with experimental data. The temperature dependences of functions S°(T), H°(T) – H°(298.15), and Фхх(T) are calculated.

The article presents the results of heat treatment (carbonization) of grade G coal of the "Saryadyr" deposit ("Pyatimetrovyy" layer) in the temperature range 250-550 degrees C at a heating rate of 10-15 degrees C/min and holding at 550 degrees C for 1, 2 and 3 hours. As a result of carbonization, carbon materials (CM) were obtained. Using the methods of thermogravimetric, energy dispersive X-ray spectroscopy, electron microscopy, we studied the technical, elemental composition, and surface morphology of the obtained products. The electrophysical characteristics of the CM were determined by measuring the electrical resistance (R), electric intensity (C), and dielectric constant (epsilon) of the samples in the temperature range 293-483 K. Based on the data obtained, the band gap (Delta E) of the samples was calculated. The carbon material obtained at 550 degrees C for 3 hours has a dielectric constant of 740 thousand at 293 K and will increase to 1.1 billion at 453 K, i.e. up to 109 degrees to colossal values and is a very attractive material for microelectronics, i.e. at 453 K, epsilon CM is higher than the reference BaTiO3 by about 540 thousand times.

The chemical analysis of a porous carbon material (PCM) from coal of the Maikube coal basin (Kazakhstan) was carried out in this work. The PCM was obtained by carbonization and activation in argon and water vapor atmospheres. The physicochemical characteristics and surface morphology of the test sample were studied. The electrophysical characteristics of the PCM were determined by measuring the electric capacity of the samples in a temperature range of 293–483 K. The temperature dependences of the specific heat were obtained by dynamic calorimetry. Equations of the temperature dependence of the heat capacity were derived, and they can be further used to determine the thermal conductivity and temperature conductivity.