The Iron Sulfides Crystal Growth from the Halide Melts

Zavrazhnov, A. Yu.; Наумов, А. В.; Kosyakov, A.V.; Berezin, S.; Volkov, V. A.; Sergeeva, Anastasya

doi:10.1590/1980-5373-mr-2017-0648

Cited by 6 publications

(3 citation statements)

References 22 publications

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“…In recent papers [101,102], we were able to develop a method of chemical transport reactions to regulate the composition of the binary phases and to apply it to obtain single crystals of ferric sulphides with a controlled phase and nonstoichiometric composition. The novelty of the developed and applied technique was that a liquid phase based on iron dihalogenide melts was used as a carrier medium for the transported component (iron).…”

Section: Using the Auxiliary Component For Fine Tune Regulation Of Th...mentioning

confidence: 99%

The development of methods for the research and synthesis of solid phases by the scientific school of Ya. A Ugai. Review

Semenova

Zavrazhnov

2021

kcmf

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The scientific school founded by Yakov A. Ugai has existed at Voronezh State University for over fifty years. One of its focus areas has been the development of physics and chemistry for obtaining solid phases in systems with volatile components. This determined the necessity to develop methods for the investigation of vapour pressure (tensimetric methods). This article only focuses on some of the works by the VSU staff dedicated to the study and construction of P-T-x diagrams. This review analyses phase equilibria and the nature of the intermediate phases in the AIV – BV, AIV – BV – СV, and AIII – BVI systems.Owing to the special nature of the cation-cation and anion-anion bonds, these compounds have highly specific properties that make them promising materials (2D materials in particular). The article presents an overview of works devoted to the construction of P-T-x diagrams and the investigation of defect formation processes in binary and ternary systems based on AIVBV compounds. It should be emphasised that the known techniques needed updating due to the high values of vapour pressure. This allowed conducting experiments at pressures of about 35-40 atmospheres. The study of the AIII - BVI systems,on the contrary, is complicated by low values of vapour pressure over indium and gallium chalcogenides and the complex composition of the vapour. For such systems the auxiliary component method was developed. The possibilities of its application are wide and are not limited to AIIIBVI compounds. A new method for nonstoichiometry regulation was developed and applied using non-destructive selective chemical transport reactions (i.e. with the participation of an auxiliary component). This method is based on the introduction or removal of one of the sample components by means of a selective chemical transport reaction. In conclusion, the development of methods for the research and synthesis of intermediate phases with variable compositions (properties) was analysed based on the example of the discussed systems.

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Section: Using the Auxiliary Component For Fine Tune Regulation Of Th...mentioning

confidence: 99%

The development of methods for the research and synthesis of solid phases by the scientific school of Ya. A Ugai. Review

Semenova

Zavrazhnov

2021

kcmf

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“…Заметим, что контакт конденсированных фаз с паром вспомогательного компонента в ряде случаев способствует не только достижению положения равновесия, но и устранению метастабильных состояний. Так, в [22] показано, что марказит (a-FeS 2 ) является метастабильной фазой по отношению к пириту (b-FeS 2 ). Это было показано монотропным превращением марказита в пирит, которое происходило только при контакте с жидкой фазой -переносчиком железа (FeCl 2 ).…”

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High-temperature spectrophotometry of indium chloride vapours as a method of study of the In – Se system

Brezhnev

Kosyakov

Steich

et al. 2021

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The goals of this work are as follows: (а) searching for a method of study of the In – Se system taking into account the specified problems and difficulties, (b) choosing a way for the instrumental implementation of this method, and (c) obtaining experimental evidence that this method and its implementation are promising. The choice of the In – Se system is related to the fact that indium selenides, layered structures and semiconductor phases with stoichiometric vacancies, are promising from the point of view of materials science. This choice is also related to the use of binary precursors for the synthesis of heterostructures based on CIS compounds.We studied the possibility of applying the auxiliary component method using the equilibrium with the participation of indium chloride vapours which were made to contact the condensed phases of the In – Se system. Equilibrium was achieved using high-temperature spectrophotometry of the vapour phase. The experiment had two stages. During the first stage we determined the absorption characteristics of the InCl3 vapour. During the second stage we studied the heterogeneous equilibrium of the unsaturated indium chloride vapour with several phases of the In – Se system. Over the course of the study, we determined the molar attenuation coefficients of the InCl3 vapour and plotted the temperature dependences of the value KP.It was found that the phase composition of the alloys significantly influences the position of the corresponding lines on the KP–T diagram, which proves the possibility of using the suggested auxiliary component method in its specific instrumental (spectrophotometric) implementation in order to study the In – Se system. We also showed the additional possibilities of using this method for plotting T-x diagrams of binary systems in such high-temperature areas where the binary solid phase is in equilibrium with the melt. This application of the method is related to the solubility of a vapour of an auxiliary component (chlorine in the form of indium chlorides) in the melts of binary phases (indium selenides).

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“…Marcasite-FeS 2 , called formerly 'white iron pyrite', is a metastable phase with an orthorhombic crystal structure. This sulphide grows under acidic conditions and low temperature [1][2][3][4][5][6] . The mineral has a chemical composition similar to pyrite (known as 'fool's gold'), more pale-yellow silvery colours, and its predominant morphologies are well distinguishable.…”

Section: Introductionmentioning

confidence: 99%

Surfaces, Interfaces and Crystal Growth of Marcasite FeS2

Arrouvel

2021

Mat. Res.

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Marcasite mineral is a metastable iron sulphide, α-FeS 2 , less known and less abundant than pyrite β-FeS 2. Their chemical compositions are similar, formed by S 2 2dimers and Fe 2+ species, but the marcasite crystal structure is orthorhombic while pyrite is cubic. The thermodynamic stability of a range of selected surfaces and their kinetic growth are analysed with molecular mechanics simulations implemented in METADISE code. The most stable surface of marcasite corresponds to the (101) surface having the lowest surface energy (marcasite 101 γ = 1.06 Jm-2) and the most favoured kinetic growth rate is expected for the [010] direction (the attachment energy of (010) surface is 0.20 |eV|/at). Mirror twinning is another characteristic of the mineral contributing to a distinctive crystal growth forming different shapes such as striated needles or pseudo-pentagonal flowers. Similarities, differences and overgrowth between the two dimorphs are highlighted.

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The Iron Sulfides Crystal Growth from the Halide Melts

Cited by 6 publications

References 22 publications

The development of methods for the research and synthesis of solid phases by the scientific school of Ya. A Ugai. Review

The development of methods for the research and synthesis of solid phases by the scientific school of Ya. A Ugai. Review

High-temperature spectrophotometry of indium chloride vapours as a method of study of the In – Se system

Surfaces, Interfaces and Crystal Growth of Marcasite FeS2

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