Pub Date : 2023-06-26DOI: 10.33609/2708-129x.89.05.2023.3-12
B. Belan, Svitala Pukas, M. Dzevenko, M. Manyako, B. Kuzhel, R. Gladyshevskii
The structure of LaNi9Si4 compound has been investigated by X-ray powder ans single crystal method. This silicide crystalize in CeNi8.5Si4 structure type: space group I4 mcm, Pearson symbol tI56, а = 7.86415(6), с = 11.5101(1) Å, RB = 0.0653; а = 7.83933(17), с = 11.4472(5) Å, R = 0.0220, wR = 0.0734 for X-ray single crystal data. Unlike the prototype CeNi8.5Si4.5, where the Wyckoff position 4d is occupied by mixture of Ni and Si atoms, in the structure of the ternary silicide LaNi9Si4, the atoms are ordered in all Wyckoff positions. Additionally, the electrical properties for the compound were investigated. The temperature dependence of the electrical resistivity exhibits metal behaviour (ρ0 = 121.60 μΩ∙cm, θD = 191 K, A = 2.2·10-9 μΩ∙m∙K-3).
用x射线粉末法和单晶法研究了LaNi9Si4化合物的结构。该硅化物结晶为CeNi8.5Si4结构类型:空间群I4 mcm, Pearson符号tI56， η = 7.86415(6)， η = 11.5101(1) Å， RB = 0.0653;x -射线单晶数据的R = 0.0220, wR = 0.0734, R = 7.83933(17)， R = 11.4472(5) Å。不同于原型CeNi8.5Si4.5的Wyckoff位置4d被Ni和Si原子的混合物占据，在三元硅化物LaNi9Si4的结构中，原子在所有Wyckoff位置上都是有序的。此外，还研究了该化合物的电学性能。电阻率的温度依赖性表现为金属行为(ρ0 = 121.60 μΩ∙cm， θD = 191 K, A = 2.2·10-9 μΩ∙m∙K-3)。
{"title":"LaNi9Si4: CRYSTAL STRUCTURE AND ELECTRICAL PROPERTIES","authors":"B. Belan, Svitala Pukas, M. Dzevenko, M. Manyako, B. Kuzhel, R. Gladyshevskii","doi":"10.33609/2708-129x.89.05.2023.3-12","DOIUrl":"https://doi.org/10.33609/2708-129x.89.05.2023.3-12","url":null,"abstract":"The structure of LaNi9Si4 compound has been investigated by X-ray powder ans single crystal method. This silicide crystalize in CeNi8.5Si4 structure type: space group I4 mcm, Pearson symbol tI56, а = 7.86415(6), с = 11.5101(1) Å, RB = 0.0653; а = 7.83933(17), с = 11.4472(5) Å, R = 0.0220, wR = 0.0734 for X-ray single crystal data. Unlike the prototype CeNi8.5Si4.5, where the Wyckoff position 4d is occupied by mixture of Ni and Si atoms, in the structure of the ternary silicide LaNi9Si4, the atoms are ordered in all Wyckoff positions. Additionally, the electrical properties for the compound were investigated. The temperature dependence of the electrical resistivity exhibits metal behaviour (ρ0 = 121.60 μΩ∙cm, θD = 191 K, A = 2.2·10-9 μΩ∙m∙K-3). \u0000 ","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76248300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.33609/2708-129x.89.05.2023.37-52
Leon Shteinberg
Chlorine-containing condensing agents (PCl3, TiCl4, SiCl4) are widely used in the synthesis of carboxylic acid arylamides by the reaction of arylamines with carboxylic acids in stoichiometric amounts, and often in excess (40–150 mol % relative to the latter). To find the optimal amount of the condensing agent used, the acylation of aniline with 3-hydroxy-2-naphthoic acid in boiling ortho-xylene was studied in the PCl3 concentration range of 0–10 mol % from 3-hydroxy-2-naphthoic acid. It has been established that phosphorus tri-chlorochloride plays the role of a condensing agent and a catalyst, while 3-hydroxy-2-naphthoic acid anilide is formed along two routes with different rates, which can be separated kinetically. The first route includes the rapid synthesis of acid chloride, its interaction with aniline to obtain the target product. The second route is implemented due to phosphorous acid, which is formed from phosphorus trichloride and is a true acylation catalyst. The maximum yield of anilide 3-hydroxy-2-naphthoic acid decreases with increasing catalyst concentration, approximately propor-tional to the amount of aniline phosphite formed from it in the mass, which, apparently, is not reactive when interacting with the starting acid. Similar patterns were also found in the acylation of aniline with benzoic and salicylic acids in the presence of phosphorus trichloride; benzoic acid in the presence of titanium tetrachloride; 3-hydroxy-2-naphthoic acid in the presence of silicon tetrachloride. They allow a new look at the role of these products (PCl3, TiCl4, SiCl4) as condensing agents and/or catalysts in the synthesis of amides of carboxylic acids. Taking into account the obtained results, in practice it is better to use PCl3 as a catalyst in an amount not exceeding 2–2.5%, or even to replace it with phosphorous acid. This allows to completely get rid of the release of hydrogen chloride, significantly reduce the consumption rates for raw materials, simplify the entire technological process, reduce the amount of waste, ensure the yield of 3-hydroxy-2-naphthoic acid anilide close to quantitative, create a direct catalytic amidation technology that fully meets the criteria «green» chemistry processes.
{"title":"THE INFLUENCE OF THE CONCENTRATION OF CHLORINE-CONTAINING CONDENSING AGENTS IN THE SYNTHESIS OF CARBOXYLIC ACID ANILIDESТ","authors":"Leon Shteinberg","doi":"10.33609/2708-129x.89.05.2023.37-52","DOIUrl":"https://doi.org/10.33609/2708-129x.89.05.2023.37-52","url":null,"abstract":"Chlorine-containing condensing agents (PCl3, TiCl4, SiCl4) are widely used in the synthesis of carboxylic acid arylamides by the reaction of arylamines with carboxylic acids in stoichiometric amounts, and often in excess (40–150 mol % relative to the latter). To find the optimal amount of the condensing agent used, the acylation of aniline with 3-hydroxy-2-naphthoic acid in boiling ortho-xylene was studied in the PCl3 concentration range of 0–10 mol % from 3-hydroxy-2-naphthoic acid. It has been established that phosphorus tri-chlorochloride plays the role of a condensing agent and a catalyst, while 3-hydroxy-2-naphthoic acid anilide is formed along two routes with different rates, which can be separated kinetically. The first route includes the rapid synthesis of acid chloride, its interaction with aniline to obtain the target product. The second route is implemented due to phosphorous acid, which is formed from phosphorus trichloride and is a true acylation catalyst. \u0000The maximum yield of anilide 3-hydroxy-2-naphthoic acid decreases with increasing catalyst concentration, approximately propor-tional to the amount of aniline phosphite formed from it in the mass, which, apparently, is not reactive when interacting with the starting acid. \u0000Similar patterns were also found in the acylation of aniline with benzoic and salicylic acids in the presence of phosphorus trichloride; benzoic acid in the presence of titanium tetrachloride; 3-hydroxy-2-naphthoic acid in the presence of silicon tetrachloride. They allow a new look at the role of these products (PCl3, TiCl4, SiCl4) as condensing agents and/or catalysts in the synthesis of amides of carboxylic acids. \u0000Taking into account the obtained results, in practice it is better to use PCl3 as a catalyst in an amount not exceeding 2–2.5%, or even to replace it with phosphorous acid. This allows to completely get rid of the release of hydrogen chloride, significantly reduce the consumption rates for raw materials, simplify the entire technological process, reduce the amount of waste, ensure the yield of 3-hydroxy-2-naphthoic acid anilide close to quantitative, create a direct catalytic amidation technology that fully meets the criteria «green» chemistry processes.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91264415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-25DOI: 10.33609/2708-129x.89.04.2023.73-89
N. Semenishyn, N. Rusakova, S. Smola
This review is devoted to different synthetic approaches for obtaining lanthanide complexes with porphyrins and phthalocyanines, studying their structure and emission features. Lanthanide-tetrapyrroles can be core-coordinated or/and coordinated by additional binding sites in polytopic derivatives. It is noteworthy that the polytopic tetrapyrroles allow obtaining polyheteronuclear compounds, which is quite interesting in terms of their particular 4f-sensitization mechanism. A general structural difference between core-coordinated lanthanide-porphyrins and lanthanide-phthalocyanines is the ability of the latter to easily form poly-decker compounds, which leads to interesting changes in photochemical processes including 4f-sensitization. The review also shows the main directions for the solution of the stability issue as well as different approaches for increasing the 4f-luminescence effectiveness.
{"title":"LANTHANIDE-PORPHYRINS AND LANTHANIDE-PHTHALOCYANINES: DEVELOPMENT OF STABLE AND EFFECTIVE INFRARED 4F-EMITTIVE COMPOUNDS","authors":"N. Semenishyn, N. Rusakova, S. Smola","doi":"10.33609/2708-129x.89.04.2023.73-89","DOIUrl":"https://doi.org/10.33609/2708-129x.89.04.2023.73-89","url":null,"abstract":"This review is devoted to different synthetic approaches for obtaining lanthanide complexes with porphyrins and phthalocyanines, studying their structure and emission features. Lanthanide-tetrapyrroles can be core-coordinated or/and coordinated by additional binding sites in polytopic derivatives. It is noteworthy that the polytopic tetrapyrroles allow obtaining polyheteronuclear compounds, which is quite interesting in terms of their particular 4f-sensitization mechanism. A general structural difference between core-coordinated lanthanide-porphyrins and lanthanide-phthalocyanines is the ability of the latter to easily form poly-decker compounds, which leads to interesting changes in photochemical processes including 4f-sensitization. The review also shows the main directions for the solution of the stability issue as well as different approaches for increasing the 4f-luminescence effectiveness.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84057277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-25DOI: 10.33609/2708-129x.89.04.2023.115-123
R. Panteleimonov, K. Pershina, Yurii V. Shmatok
The impact of the nature of electrically conductive graphite and graphene admixtures in spinel LiMn2O4 with different degrees of dispersion, composition and morphology on the surface element distribution and the cycling ability under current loads from 0.5 to 8 C of composite cathode materials based on such spinels have been studied by the methods of electron microscopy, X-ray spectrometry, the BET method and galvanostatic-potentiostatic cycling. The specific surface of graphene structures was studied, which was 23 m2/g for G-N and 27.7 m2/g for G-H2O, and the porosity was about 100 nm for the above samples. It was established that the degree of dispersion of spinel affects not only the morphology of the surface of the electrodes, but also the distribution of elements, primarily manganese and oxygen, which take part in electrode redox reactions, as well as the content of the carbon component. Using the elemental analysis of the component composition of the surface, the ratio of manganese to oxygen was calculated, and it was shown that in samples with graphite, manganese is in a more reduced state, and the maximum oxidized state of manganese is observed in samples with graphene, which was synthesized from an aqueous medium. In the case of finely dispersed spinel, the dependence of the carbon content and the ratio of manganese to oxygen on the surface has an antibate character relative to samples with coarsely dispersed spinel and correlates with the number of mesopores on the surface. The dependence of the degree of dispersion and the oxidation state of manganese is in good agreement with the dependence of specific capacity on the discharge current density for composite electrodes. In XDM spinel with graphene synthesized from an aqueous medium, the obtained capacitive characteristics exceed the other characteristics of the materials by 20%. It has been experimentally proven that by changing the nature of the impurity and the degree of dispersion of the spinel, it is possible to adjust the capacitive properties and resistance to current loads of composite electrodes.
{"title":"ІMPACT OF THE NATURE OF ELECTRICALLY CONDUCTIVE IMPURITY ON CAPACITIVE PROPERTIES AND RESISTANCE TO CURRENT LOADS OF CATHODE MATERIALS BASED ON LiMn2O4","authors":"R. Panteleimonov, K. Pershina, Yurii V. Shmatok","doi":"10.33609/2708-129x.89.04.2023.115-123","DOIUrl":"https://doi.org/10.33609/2708-129x.89.04.2023.115-123","url":null,"abstract":"The impact of the nature of electrically conductive graphite and graphene admixtures in spinel LiMn2O4 with different degrees of dispersion, composition and morphology on the surface element distribution and the cycling ability under current loads from 0.5 to 8 C of composite cathode materials based on such spinels have been studied by the methods of electron microscopy, X-ray spectrometry, the BET method and galvanostatic-potentiostatic cycling. The specific surface of graphene structures was studied, which was 23 m2/g for G-N and 27.7 m2/g for G-H2O, and the porosity was about 100 nm for the above samples. It was established that the degree of dispersion of spinel affects not only the morphology of the surface of the electrodes, but also the distribution of elements, primarily manganese and oxygen, which take part in electrode redox reactions, as well as the content of the carbon component. Using the elemental analysis of the component composition of the surface, the ratio of manganese to oxygen was calculated, and it was shown that in samples with graphite, manganese is in a more reduced state, and the maximum oxidized state of manganese is observed in samples with graphene, which was synthesized from an aqueous medium. In the case of finely dispersed spinel, the dependence of the carbon content and the ratio of manganese to oxygen on the surface has an antibate character relative to samples with coarsely dispersed spinel and correlates with the number of mesopores on the surface. The dependence of the degree of dispersion and the oxidation state of manganese is in good agreement with the dependence of specific capacity on the discharge current density for composite electrodes. In XDM spinel with graphene synthesized from an aqueous medium, the obtained capacitive characteristics exceed the other characteristics of the materials by 20%. It has been experimentally proven that by changing the nature of the impurity and the degree of dispersion of the spinel, it is possible to adjust the capacitive properties and resistance to current loads of composite electrodes.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75110667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-25DOI: 10.33609/2708-129x.89.04.2023.90-101
O. Boychuk, K. Pershina, E. Kolomiets, Yelyzaveta Pletenets
IR and X-ray analyses of bentonite modified with magnetite and enzyme established the dependence of enzyme immobilization on the presence of iron oxides. IR studies have proven that the binding of the enzyme to the carrier is adsorption in nature without stable chemical interactions. This type of binding does not significantly affect the change in the structure of the enzyme module. Characteristic bands of vibrations of amide groups of proteins were detected at 1637 cm-1 ( ν-vibrations of C=O bonds (amide I)), 713 cm-1 (δ – vibrations of O=C-N in the plane (amide IV)), which can participate in the sorption binding of the enzyme to bentonite and the SiO2 group, which is characterized by a weak connection of the outer part of protein with the formation of a surface structure, which disappears over time due to the diffusion of molecules into the pores of the mineral. Comparison of the basal distances in the samples established the following dependence: 12.43 Å bentonite+ Fe3O4+enz (48 h) > 12.38; Å natural bentonite> 12.31; Å bentonite+ Fe3O4+enz (2 hours) > 11.91; Å bentonite+ Fe3O4 , which indicates a high probability of iron compounds entering the interlayer space due to the hydrolysis of magnetite with the formation of Fe-(OH)n bonds and unstable compounds. According to the research results, a scheme of the interaction of the enzyme with modified layered iron aluminosilicate is proposed: 1 – transport of the enzyme to the surface (phase distribution boundaries); 2 – deformation of the enzyme under the action of the surface as a result of a polycondensation reaction with the formation of water molecules; 3 – entry of water molecules into the interlayer space; 4 – hydrolysis of magnetite particles; 5 – extraction of iron hydroxide from the interlayer space due to the formation of aggregates with an enzyme molecule that has a related adsorption center.
对氧化铁改性膨润土的红外和x射线分析表明，氧化铁的存在对酶的固定化具有依赖性。红外研究证明，酶与载体的结合在本质上是吸附的，没有稳定的化学相互作用。这种类型的结合不会显著影响酶模块结构的变化。Characte-ristic频段的振动酰胺组蛋白的检测在1637 cm - 1(ν—C = O债券(我)酰胺),713 cm - 1(δ- O =碳氮的振动平面(酰胺(四)),它可以参与酶的吸附结合膨润土和二氧化硅集团的特点是弱连接外部的蛋白质与表面结构的形成,随着时间的推移而消失,由于分子扩散进入毛孔的矿物。对比样品中的基距，建立了以下关系:12.43 Å膨润土+ Fe3O4+enz (48 h) > 12.38;Å天然膨润土- the > 12.31;Å膨润土+ Fe3O4+enz(2小时)> 11.91;Å膨润土+ Fe3O4，表明由于磁铁矿水解形成Fe-(OH)n键和不稳定化合物，铁化合物极有可能进入层间空间。根据研究结果，提出了一种酶与改性层状铝硅酸铁相互作用的方案:1 -酶向表面运输(相分布边界);2 -酶在表面作用下发生变形，产生缩聚反应，形成水分子;3 -水分子进入层间空间;4 -磁铁矿颗粒的水解;5 -由于与具有相关吸附中心的酶分子形成聚集体，从层间空间中提取氢氧化铁。
{"title":"CHARACTERISTICS OF THE BINDING BETWEEN THE ENZYME PREPARATION RAPHANUS SATIVUS L. AND NATURAL LAYERED ALUMOSILICA IN THE PRESENCE OF IRON OXIDES","authors":"O. Boychuk, K. Pershina, E. Kolomiets, Yelyzaveta Pletenets","doi":"10.33609/2708-129x.89.04.2023.90-101","DOIUrl":"https://doi.org/10.33609/2708-129x.89.04.2023.90-101","url":null,"abstract":"IR and X-ray analyses of bentonite modified with magnetite and enzyme established the dependence of enzyme immobilization on the presence of iron oxides. IR studies have proven that the binding of the enzyme to the carrier is adsorption in nature without stable chemical interactions. This type of binding does not significantly affect the change in the structure of the enzyme module. Characteristic bands of vibrations of amide groups of proteins were detected at 1637 cm-1 ( ν-vibrations of C=O bonds (amide I)), 713 cm-1 (δ – vibrations of O=C-N in the plane (amide IV)), which can participate in the sorption binding of the enzyme to bentonite and the SiO2 group, which is characterized by a weak connection of the outer part of protein with the formation of a surface structure, which disappears over time due to the diffusion of molecules into the pores of the mineral. Comparison of the basal distances in the samples established the following dependence: 12.43 Å bentonite+ Fe3O4+enz (48 h) > 12.38; Å natural bentonite> 12.31; Å bentonite+ Fe3O4+enz (2 hours) > 11.91; Å bentonite+ Fe3O4 , which indicates a high probability of iron compounds entering the interlayer space due to the hydrolysis of magnetite with the formation of Fe-(OH)n bonds and unstable compounds. According to the research results, a scheme of the interaction of the enzyme with modified layered iron aluminosilicate is proposed: 1 – transport of the enzyme to the surface (phase distribution boundaries); 2 – deformation of the enzyme under the action of the surface as a result of a polycondensation reaction with the formation of water molecules; 3 – entry of water molecules into the interlayer space; 4 – hydrolysis of magnetite particles; 5 – extraction of iron hydroxide from the interlayer space due to the formation of aggregates with an enzyme molecule that has a related adsorption center.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76091268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-25DOI: 10.33609/2708-129x.89.04.2023.102-114
Michael Filep, A. Pogodin, I. Shender, T. Malakhovska, V. Bilanych, O. Kokhan
This paper presents the preparation of microcrystalline powders of Ag6PS5I, solid solutions of Ag6+xP1-xGexS5I (x = 0.25, 0.5, 0.75) and ceramic materials based on them. The microhardness of the ceramic samples was measured and the effect of heterovalent substitution of P5+↔Ge4+ on the mechanical properties of the studied samples was determined. The synthesis of initial Ag6PS5I and necessary for doping Ag7GeS5I was performed from the high purity elemental components (Ag, P, Ge, S) and previously synthesized binary AgI. Solid solutions of the Ag6+xP1-xGexS5I (x = 0.25, 0.5, 0.75) composition were synthesized from previously synthesised Ag6PS5I and Ag7GeS5I taken in stoichiometric amounts by a direct one-temperature method. As a result, polycrystalline bulk alloys of Ag6+xP1-xGexS5I solid were obtained. Microcrystalline Ag6+xP1-xGexS5I powders were obtained from the synthesized polycrystalline alloys by mechanical grinding (agate mortar). The powders were sieved through sieves with a pore size of 20 μm and 10 μm to obtain a fraction of crystallites with a size of 10-20 μm. The phase composition of the obtained powders was studied by means of XRD method. It has been found that the powder patterns of the studied samples are characterized by the presence only of one system of reflexes corresponding to the face-centred cubic cell with SG F-43m. The resulting micropowders were pressed (P ~ 400 MPa) in the form of discs and annealed at 650 °С in vacuum quartz ampoules. The microhardness of the ceramics obtained in this way was measured by the Vickers method. For all ceramics, a decrease in the microhardness H is observed with an increase in the load P. This indicates that a direct size effect is observed for ceramics made on the basis of solid solutions of Ag6+xP1-xGexS5I. The obtained values of microhardness at a load of P > 1–1.5 N are independent of the load, which indicates the achievement of intrinsic hardness. Meyer's law was used to further analyze the microhardness and size effect of Ag6+xP1-xGexS5I solid solutions. The obtained values of the Meyer's index for Ag6+xP1-xGexS5I based ceramics are in the range n = 1.78 ÷ 1.81, which demonstrates the implementation of a direct size effect in these samples and indicates that the studied ceramics belong to soft materials. The concentration dependence of the microhardness indicates that an increase in the Germanium content in ceramic materials of solid solutions of Ag6+xP1-xGexS5I leads to a decrease in the microhardness of the materials.
{"title":"MICROHARDNESS OF CERAMIC MATERIALS BASED ON Ge-DOPED ARGYRODITE Ag6PS5I","authors":"Michael Filep, A. Pogodin, I. Shender, T. Malakhovska, V. Bilanych, O. Kokhan","doi":"10.33609/2708-129x.89.04.2023.102-114","DOIUrl":"https://doi.org/10.33609/2708-129x.89.04.2023.102-114","url":null,"abstract":"This paper presents the preparation of microcrystalline powders of Ag6PS5I, solid solutions of Ag6+xP1-xGexS5I (x = 0.25, 0.5, 0.75) and ceramic materials based on them. The microhardness of the ceramic samples was measured and the effect of heterovalent substitution of P5+↔Ge4+ on the mechanical properties of the studied samples was determined. \u0000The synthesis of initial Ag6PS5I and necessary for doping Ag7GeS5I was performed from the high purity elemental components (Ag, P, Ge, S) and previously synthesized binary AgI. Solid solutions of the Ag6+xP1-xGexS5I (x = 0.25, 0.5, 0.75) composition were synthesized from previously synthesised Ag6PS5I and Ag7GeS5I taken in stoichiometric amounts by a direct one-temperature method. As a result, polycrystalline bulk alloys of Ag6+xP1-xGexS5I solid were obtained. \u0000Microcrystalline Ag6+xP1-xGexS5I powders were obtained from the synthesized polycrystalline alloys by mechanical grinding (agate mortar). The powders were sieved through sieves with a pore size of 20 μm and 10 μm to obtain a fraction of crystallites with a size of 10-20 μm. The phase composition of the obtained powders was studied by means of XRD method. It has been found that the powder patterns of the studied samples are characterized by the presence only of one system of reflexes corresponding to the face-centred cubic cell with SG F-43m. \u0000The resulting micropowders were pressed (P ~ 400 MPa) in the form of discs and annealed at 650 °С in vacuum quartz ampoules. The microhardness of the ceramics obtained in this way was measured by the Vickers method. For all ceramics, a decrease in the microhardness H is observed with an increase in the load P. This indicates that a direct size effect is observed for ceramics made on the basis of solid solutions of Ag6+xP1-xGexS5I. The obtained values of microhardness at a load of P > 1–1.5 N are independent of the load, which indicates the achievement of intrinsic hardness. \u0000Meyer's law was used to further analyze the microhardness and size effect of Ag6+xP1-xGexS5I solid solutions. The obtained values of the Meyer's index for Ag6+xP1-xGexS5I based ceramics are in the range n = 1.78 ÷ 1.81, which demonstrates the implementation of a direct size effect in these samples and indicates that the studied ceramics belong to soft materials. The concentration dependence of the microhardness indicates that an increase in the Germanium content in ceramic materials of solid solutions of Ag6+xP1-xGexS5I leads to a decrease in the microhardness of the materials. \u0000 ","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84298623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-28DOI: 10.33609/2708-129x.89.03.2023.37-54
N. Globa, Yurii V. Shmatok, V. Sirosh, S. Kirillov
The influence of the technological parameters of the positive electrode and the composition of the salt-solvate electrolyte LiTFSI – TEGDME on the specific characteristics of sulfur electrodes during galvanostatic cycling in lithium-sulfur cells was studied. The dependences of the change in specific capacity on the cathode composition, the charge-discharge current density, and the preservation of the charged state were discussed. It was found that the concentration of salt in salt-solvate electrolyte determines the specific characteristics of sulfur and affects its stability during cycling. It was determined that the most stable specific capacity and high Coulombic efficiency of the discharge/charge process of lithium-sulfur cells under long-term cycling conditions were ensured at lithium salt concentration of 0.4 molar fractions (m.f.) in the salt-solvate electrolyte. The positive effect of reducing the size of sulfur particles and optimizing its concentration and the composition of conductive additives in the cathode on the specific characteristics of sulfur-containing electrodes during cycling was shown. It was determined that reducing the size of sulfur particles from δS ≤ 150 μm to δS ≤ 40 μm contributes to an increase in the specific capacity of lithium-sulfur cells by approximately 20% and had a positive effect on their stability during cycling. It was established that increasing the concentration of sulfur in the cathode from 50% to 70% by mass leads to a significant decreased in the specific capacity of lithium-sulfur cells as a result of accelerated passivation of the electrode by poorly soluble lithium polysulfides. It was shown that in salt-solvate electrolytes a high level of retention of specific capacity was achieved under the conditions of long-term storage of a charged sulfur cathode at the temperature of ~30 °C. With a sulfur content of 50% and 70% by mass in the composition of the cathode with a fractional composition of δS ≤ 80 μm, the return of the specific capacity was over 97%.
{"title":"SPECIFIC CHARACTERISTICS OF SULFUR ELECTRODES IN SALT-SOLVATE ELECTROLYTES","authors":"N. Globa, Yurii V. Shmatok, V. Sirosh, S. Kirillov","doi":"10.33609/2708-129x.89.03.2023.37-54","DOIUrl":"https://doi.org/10.33609/2708-129x.89.03.2023.37-54","url":null,"abstract":"The influence of the technological parameters of the positive electrode and the composition of the salt-solvate electrolyte LiTFSI – TEGDME on the specific characteristics of sulfur electrodes during galvanostatic cycling in lithium-sulfur cells was studied. The dependences of the change in specific capacity on the cathode composition, the charge-discharge current density, and the preservation of the charged state were discussed. \u0000It was found that the concentration of salt in salt-solvate electrolyte determines the specific characteristics of sulfur and affects its stability during cycling. It was determined that the most stable specific capacity and high Coulombic efficiency of the discharge/charge process of lithium-sulfur cells under long-term cycling conditions were ensured at lithium salt concentration of 0.4 molar fractions (m.f.) in the salt-solvate electrolyte. \u0000The positive effect of reducing the size of sulfur particles and optimizing its concentration and the composition of conductive additives in the cathode on the specific characteristics of sulfur-containing electrodes during cycling was shown. It was determined that reducing the size of sulfur particles from δS ≤ 150 μm to δS ≤ 40 μm contributes to an increase in the specific capacity of lithium-sulfur cells by approximately 20% and had a positive effect on their stability during cycling. \u0000It was established that increasing the concentration of sulfur in the cathode from 50% to 70% by mass leads to a significant decreased in the specific capacity of lithium-sulfur cells as a result of accelerated passivation of the electrode by poorly soluble lithium polysulfides. \u0000It was shown that in salt-solvate electrolytes a high level of retention of specific capacity was achieved under the conditions of long-term storage of a charged sulfur cathode at the temperature of ~30 °C. With a sulfur content of 50% and 70% by mass in the composition of the cathode with a fractional composition of δS ≤ 80 μm, the return of the specific capacity was over 97%.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85087939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-28DOI: 10.33609/2708-129x.89.03.2023.15-24
V. Nikitenko, V. Kublanovsky, Yu. S. Yapontseva
The complex formation of cobalt (II) with citrate (cit3–) and molybdate (MoO42–) ions in 0.3 mol·l-1 Na2SO4 solution at 20°C was studied by spectrophotometric method. It has been established that in a citrate-molybdate electrolyte at pH 9.0, cobalt (II) ions form, depending on the ratio of the equilibrium concentrations of ligands: molybdate [Co(MoO4)2]2–, citrate [Co(cit)2]4– and polyligand complexes [Co(cit)m(MoO4)n]+2-(3m+2n). The composition of [Co(cit)(MoO4)]3– polyligand complexes was determined, the equilibrium constant Ke of the reaction of their formation and their stability constant (lgβMLX = 5.86) The dependence of the degree of formation of molybdate, citrate and polyligand complexes of cobalt (II) in citrate-molybdate electrolyte on the logarithm of the ratio of equilibrium concentrations of ligands was calculated.
{"title":"DETERMINATION OF THE COMPOSITION AND STABILITY CONSTANT OF COBALT (II) POLYLIGAND CITRATE-MOLYBDATE COMPLEXES","authors":"V. Nikitenko, V. Kublanovsky, Yu. S. Yapontseva","doi":"10.33609/2708-129x.89.03.2023.15-24","DOIUrl":"https://doi.org/10.33609/2708-129x.89.03.2023.15-24","url":null,"abstract":"The complex formation of cobalt (II) with citrate (cit3–) and molybdate (MoO42–) ions in 0.3 mol·l-1 Na2SO4 solution at 20°C was studied by spectrophotometric method. It has been established that in a citrate-molybdate electrolyte at pH 9.0, cobalt (II) ions form, depending on the ratio of the equilibrium concentrations of ligands: molybdate [Co(MoO4)2]2–, citrate [Co(cit)2]4– and polyligand complexes [Co(cit)m(MoO4)n]+2-(3m+2n). The composition of [Co(cit)(MoO4)]3– polyligand complexes was determined, the equilibrium constant Ke of the reaction of their formation and their stability constant (lgβMLX = 5.86) The dependence of the degree of formation of molybdate, citrate and polyligand complexes of cobalt (II) in citrate-molybdate electrolyte on the logarithm of the ratio of equilibrium concentrations of ligands was calculated.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85804032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-28DOI: 10.33609/2708-129x.89.03.2023.3-14
O. Kozachkova, Nataliya Tsaryk, V. Pekhnyo, V. Trachevskij, Olga Kocharovska, Oleksii Palchyk
The acid-base characteristics of ethylenediaminetetra(methylenephosphonic) (edtmp), tetramethylenediaminetetra(methylenephosphonic) (tetdtmp) and pentamethylenediaminetetra(methylenephosphonic) (pendtmp) acids were investigated by means of pH-potentiometry and 31P NMR spectroscopy. Calculated and estimated values of acid dissociation constants (pK) for edtmp (рК1<2, рК2<2, рК3=3.07, рК4=5.17, рК5=6.52, рК6=7.97, рК7=9.65, рК8=10.94), for tetdtmp (рК1<2, рК2=4.48, рК3=5.34, рК4=6.13, рК5=6.66, рК6=10.08, рК7~11.4, рК8~11.5) and for pendtmp (рК1<2, рК2=4.22, рК3=5.56, рК4=6.16, рК5=7.66, рК6=10.99, рК7~11.5, рК8~11.6) were obtained. The values of the acid dissociation constants indicate a decrease in the acidity of phosphonic groups and an increase in the basicity of amino groups with increasing hydrocarbon chain length between the two nitrogen atoms in the edtmp, tetdtmp, and pendtmpseries. Based on the values of the calculated constants for the formation of anions of tetraphosphonic acids, diagrams of the distribution of their equilibrium concentrations depending on pH were constructed, which indicate the state of acid-base equilibrium, the charge and the ratio of concentrations between anions with different degrees of protonation at certain pH values. According to the data of 31P NMR spectroscopy, the formation of intramolecular hydrogen bonds between the deprotonated oxygen atoms of one amino(methylphosphonic) group with protonated nitrogen atom of another amino(methylphosphonic) group was established in the case of edtmp. In the case of pendtmp and tetdtmp, the formation of intermolecular hydrogen bonds between distant amino(methylphosphonic) groups is impossible due to the presence of steric hindrances.
{"title":"ACID-BASE PROPERTIES OF ALKYLENEDIAMINETETRA (METHYLENEPHOSPHONIC) ACIDS","authors":"O. Kozachkova, Nataliya Tsaryk, V. Pekhnyo, V. Trachevskij, Olga Kocharovska, Oleksii Palchyk","doi":"10.33609/2708-129x.89.03.2023.3-14","DOIUrl":"https://doi.org/10.33609/2708-129x.89.03.2023.3-14","url":null,"abstract":"The acid-base characteristics of ethylenediaminetetra(methylenephosphonic) (edtmp), tetramethylenediaminetetra(methylenephosphonic) (tetdtmp) and pentamethylenediaminetetra(methylenephosphonic) (pendtmp) acids were investigated by means of pH-potentiometry and 31P NMR spectroscopy. Calculated and estimated values of acid dissociation constants (pK) for edtmp (рК1<2, рК2<2, рК3=3.07, рК4=5.17, рК5=6.52, рК6=7.97, рК7=9.65, рК8=10.94), for tetdtmp (рК1<2, рК2=4.48, рК3=5.34, рК4=6.13, рК5=6.66, рК6=10.08, рК7~11.4, рК8~11.5) and for pendtmp (рК1<2, рК2=4.22, рК3=5.56, рК4=6.16, рК5=7.66, рК6=10.99, рК7~11.5, рК8~11.6) were obtained. The values of the acid dissociation constants indicate a decrease in the acidity of phosphonic groups and an increase in the basicity of amino groups with increasing hydrocarbon chain length between the two nitrogen atoms in the edtmp, tetdtmp, and pendtmpseries. Based on the values of the calculated constants for the formation of anions of tetraphosphonic acids, diagrams of the distribution of their equilibrium concentrations depending on pH were constructed, which indicate the state of acid-base equilibrium, the charge and the ratio of concentrations between anions with different degrees of protonation at certain pH values. \u0000According to the data of 31P NMR spectroscopy, the formation of intramolecular hydrogen bonds between the deprotonated oxygen atoms of one amino(methylphosphonic) group with protonated nitrogen atom of another amino(methylphosphonic) group was established in the case of edtmp. In the case of pendtmp and tetdtmp, the formation of intermolecular hydrogen bonds between distant amino(methylphosphonic) groups is impossible due to the presence of steric hindrances.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91207658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-28DOI: 10.33609/2708-129x.89.03.2023.25-36
Olha Medvezhynska, A. Omel’chuk, I. Shvaika, Igor Shvayka, L. Proskurka
The interaction of tungsten (VI) oxide and calcium tungstate with a molten eutectic mixture of calcium-sodium chlorides in the temperature range from 600 to 800 °С was investigated by the methods of isothermal saturation, mass spectrometry with inductively coupled plasma (ICP–MS) and X-ray phase analysis. It was noted that the solubility of both tungsten trioxide and calcium tungstate depends to a large extent on temperature. Thus, in the temperature range from 600 to 700 °C, the equilibrium concentration of tungsten increases by an average of 1.7 times, and in the range from 700 to 800 °C, its values increase by 3.9 times. Based on the results obtained by inductively coupled plasma mass spectrometry, it was found that the equilibrium content of tungsten (in the calculation of pure metal) in the molten eutectic mixture of sodium and calcium chlorides both in contact with tungsten trioxide and in contact with calcium tungstate at different temperatures within the error of definition has approximately the same values. The obtained results indicate in favor of the fact that the dissolution of tungsten trioxide in the molten mixture of sodium and calcium chlorides proceeds through the stage of formation of calcium tungstate. It is possible that sodium tungstate may be formed in this case, but no direct evidence of this has been found. At temperatures higher than 750 °C, almost all of the loaded tungsten trioxide turns into calcium tungstate. This gives grounds for asserting that in the molten salt phase tungsten is mainly in the form of calcium tungstate. The obtained results give reason to consider that the interaction of the mentioned oxygen-containing compounds of tungsten produces homogeneous salt phases of the ternary system CaCl2–NaCl–CaWO4, the content of which calcium tungstate in the temperature range of 700÷800 °С is satisfactorily described by the dependence ln S = 8.331 – 14057/T.
{"title":"THE INTERACTION OF TUNGSTEN (VI) OXIDE AND CALCIUM TUNGSTATE IN THE CaCl2–NaCl EUTECTIC MELT","authors":"Olha Medvezhynska, A. Omel’chuk, I. Shvaika, Igor Shvayka, L. Proskurka","doi":"10.33609/2708-129x.89.03.2023.25-36","DOIUrl":"https://doi.org/10.33609/2708-129x.89.03.2023.25-36","url":null,"abstract":"The interaction of tungsten (VI) oxide and calcium tungstate with a molten eutectic mixture of calcium-sodium chlorides in the temperature range from 600 to 800 °С was investigated by the methods of isothermal saturation, mass spectrometry with inductively coupled plasma (ICP–MS) and X-ray phase analysis. It was noted that the solubility of both tungsten trioxide and calcium tungstate depends to a large extent on temperature. Thus, in the temperature range from 600 to 700 °C, the equilibrium concentration of tungsten increases by an average of 1.7 times, and in the range from 700 to 800 °C, its values increase by 3.9 times. \u0000Based on the results obtained by inductively coupled plasma mass spectrometry, it was found that the equilibrium content of tungsten (in the calculation of pure metal) in the molten eutectic mixture of sodium and calcium chlorides both in contact with tungsten trioxide and in contact with calcium tungstate at different temperatures within the error of definition has approximately the same values. The obtained results indicate in favor of the fact that the dissolution of tungsten trioxide in the molten mixture of sodium and calcium chlorides proceeds through the stage of formation of calcium tungstate. It is possible that sodium tungstate may be formed in this case, but no direct evidence of this has been found. At temperatures higher than 750 °C, almost all of the loaded tungsten trioxide turns into calcium tungstate. This gives grounds for asserting that in the molten salt phase tungsten is mainly in the form of calcium tungstate. \u0000The obtained results give reason to consider that the interaction of the mentioned oxygen-containing compounds of tungsten produces homogeneous salt phases of the ternary system CaCl2–NaCl–CaWO4, the content of which calcium tungstate in the temperature range of 700÷800 °С is satisfactorily described by the dependence ln S = 8.331 – 14057/T.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75890460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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