Special Issue "Rietveld Refinement in the Characterization of Crystalline Materials"

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Crystalline Materials".

Deadline for manuscript submissions: closed (31 July 2018)

Special Issue Editor

Guest Editor
Prof. Dr. Igor Djerdj

Josip Juraj Strossmayer University of Osijek, Department of Chemistry, Osijek, Croatia
Website | E-Mail
Interests: sol-gel synthesis; nanoparticles; heterogeneous catalysis; multiferroics; gas sensing materials; Rietveld analysis; transmission electron microscopy; XRD

Special Issue Information

Dear Colleagues,

Nowadays, various crystalline materials are essential in our world due to their broad technological applications arising from their properties: ceramics in engineering, semiconductors in electronic industry, porous materials in catalysis and various families of compounds in sensor industry. In order to understand and tailor the properties of crystalline materials, the atomic structure has to be known. The common used techniques to do this are diffraction techniques using neutrons from neutron sources or X-rays from laboratory sources and synchrotrons. Most materials of technological interest appear in the polycrystalline form with strong tendency to consist of very small crystallites. For those system, the accurate determination of the crystal structure and microstructure has been routinely done using the Rietveld method.  

The current special issue focuses on the implementation of the Rietveld refinement of powder X-ray or neutron diffraction data as an advanced analysis tool for the extraction of structural and microstructural features of various crystalline materials.   

We look forward to receiving your contributions to these issue.

Prof. Dr. Igor Djerdj
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Rietveld method
  • Crystalline materials
  • Functional materials
  • Structural materials
  • Microstructural analysis
  • Structural characterization
  • X-ray and neutron diffraction

Published Papers (7 papers)

View options order results:
result details:
Displaying articles 1-7
Export citation of selected articles as:

Research

Open AccessArticle Application of Evolutionary Rietveld Method Based XRD Phase Analysis and a Self-Configuring Genetic Algorithm to the Inspection of Electrolyte Composition in Aluminum Electrolysis Baths
Crystals 2018, 8(11), 402; https://doi.org/10.3390/cryst8110402
Received: 30 August 2018 / Revised: 19 October 2018 / Accepted: 22 October 2018 / Published: 24 October 2018
PDF Full-text (1672 KB) | HTML Full-text | XML Full-text
Abstract
The technological inspection of the electrolyte composition in aluminum production is performed using calibration X-ray quantitative phase analysis (QPA). For this purpose, the use of QPA by the Rietveld method, which does not require the creation of multiphase reference samples and is able
[...] Read more.
The technological inspection of the electrolyte composition in aluminum production is performed using calibration X-ray quantitative phase analysis (QPA). For this purpose, the use of QPA by the Rietveld method, which does not require the creation of multiphase reference samples and is able to take into account the actual structure of the phases in the samples, could be promising. However, its limitations are in its low automation and in the problem of setting the correct initial values of profile and structural parameters. A possible solution to this problem is the application of the genetic algorithm we proposed earlier for finding suitable initial parameter values individually for each sample. However, the genetic algorithm also needs tuning. A self-configuring genetic algorithm that does not require tuning and provides a fully automatic analysis of the electrolyte composition by the Rietveld method was proposed, and successful testing results were presented. Full article
(This article belongs to the Special Issue Rietveld Refinement in the Characterization of Crystalline Materials)
Figures

Graphical abstract

Open AccessArticle Structural Identification of Binary Tetrahydrofuran + O2 and 3-Hydroxytetrahydrofuran + O2 Clathrate Hydrates by Rietveld Analysis with Direct Space Method
Crystals 2018, 8(8), 328; https://doi.org/10.3390/cryst8080328
Received: 24 July 2018 / Revised: 14 August 2018 / Accepted: 14 August 2018 / Published: 18 August 2018
PDF Full-text (2046 KB) | HTML Full-text | XML Full-text
Abstract
The structural determination of clathrate hydrates, nonstoichiometric crystalline host-guest materials, is challenging because of the dynamical disorder and partial cage occupancies of the guest molecules. The application of direct space methods with Rietveld analysis can determine the powder X-ray diffraction (PXRD) patterns of
[...] Read more.
The structural determination of clathrate hydrates, nonstoichiometric crystalline host-guest materials, is challenging because of the dynamical disorder and partial cage occupancies of the guest molecules. The application of direct space methods with Rietveld analysis can determine the powder X-ray diffraction (PXRD) patterns of clathrates. Here, we conducted Rietveld analysis with the direct space method for the structural determination of binary tetrahydrofuran (THF) + O2 and 3-hydroxytetrahydrofuran (3-OH THF) + O2 clathrate hydrates in order to identify the hydroxyl substituent effect on interactions between the host framework and the cyclic ether guest molecules. The refined PXRD results reveal that the hydroxyl groups are hydrogen-bonded to host hexagonal rings of water molecules in the 51264 cage, while any evidences of hydrogen bonding between THF guests and the host framework were not observed from PXRD at 100 K. This guest-host hydrogen bonding is thought to induce slightly larger 512 cages in the 3-OH THF hydrate than those in the THF hydrate. Consequently, the disorder dynamics of the secondary guest molecules also can be affected by the hydrogen bonding of larger guest molecules. The structural information of binary clathrate hydrates reported here can improve the understanding of the host-guest interactions occurring in clathrate hydrates and the specialized methodologies for crystal structure determination of clathrate hydrates. Full article
(This article belongs to the Special Issue Rietveld Refinement in the Characterization of Crystalline Materials)
Figures

Figure 1

Open AccessArticle Does Thermosalient Effect Have to Concur with a Polymorphic Phase Transition? The Case of Methscopolamine Bromide
Crystals 2018, 8(7), 301; https://doi.org/10.3390/cryst8070301
Received: 14 June 2018 / Revised: 16 July 2018 / Accepted: 19 July 2018 / Published: 21 July 2018
PDF Full-text (2767 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In this paper, we report for the first time an observed thermosalient effect that is not accompanied with a phase transition. Our experiments found that methscolopamine bromide—a compound chemically very similar to another thermosalient material, oxitropium bromide—exhibited crystal jumps during heating in the
[...] Read more.
In this paper, we report for the first time an observed thermosalient effect that is not accompanied with a phase transition. Our experiments found that methscolopamine bromide—a compound chemically very similar to another thermosalient material, oxitropium bromide—exhibited crystal jumps during heating in the temperature range of 323–340 K. The same behavior was observed during cooling at a slightly lower temperature range of 313–303 K. Unlike other thermosalient solids reported so far, no phase transition was observed in this system. However, similar to other thermosalient materials, methscolopamine showed unusually large and anisotropic thermal expansion coefficients. This indicates that the thermosalient effect in this compound is caused by a different mechanism compared to all other reported materials, where it is governed by sharp and rapid phase transition. By contrast, thermosalient effect seems to be a continuous process in methscolopamine bromide. Full article
(This article belongs to the Special Issue Rietveld Refinement in the Characterization of Crystalline Materials)
Figures

Figure 1

Open AccessArticle Heavily Boron Doped Diamond Powder: Synthesis and Rietveld Refinement
Crystals 2018, 8(7), 297; https://doi.org/10.3390/cryst8070297
Received: 9 June 2018 / Revised: 16 July 2018 / Accepted: 17 July 2018 / Published: 19 July 2018
PDF Full-text (2046 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Boron-doped diamonds were synthesized by the reaction of an amorphous globular carbon powder (80%) with a powder of 1,7-di (oxymethyl)-M-carborane (20%) in a ‘toroid’-type high-pressure chamber at a pressure of 8.0 GPa and temperature of 1700 °C. The structure was refined by the
[...] Read more.
Boron-doped diamonds were synthesized by the reaction of an amorphous globular carbon powder (80%) with a powder of 1,7-di (oxymethyl)-M-carborane (20%) in a ‘toroid’-type high-pressure chamber at a pressure of 8.0 GPa and temperature of 1700 °C. The structure was refined by the Rietveld method according to the X-ray powder diffraction data. It was shown that the unit cell parameters of these diamonds have two discrete quantities: around 3.570 Å for small concentrations of B (~1–1.5%) and around 3.578 Å for large concentrations of B (~2–3%). The concentration of the vacancies in the diamonds exceeds the concentration of boron atoms by 2–3 fold. This fact can play an important role in the formation of the structure and in determining the physical properties of diamonds. Full article
(This article belongs to the Special Issue Rietveld Refinement in the Characterization of Crystalline Materials)
Figures

Graphical abstract

Open AccessArticle The Effect of Skelp Thickness on Precipitate Size and Morphology for X70 Microalloyed Steel Using Rietveld Refinement (Quantitative X-ray Diffraction)
Crystals 2018, 8(7), 287; https://doi.org/10.3390/cryst8070287
Received: 11 June 2018 / Revised: 29 June 2018 / Accepted: 29 June 2018 / Published: 12 July 2018
PDF Full-text (5483 KB) | HTML Full-text | XML Full-text
Abstract
Precipitates in thin-walled (11 mm) and thick-walled X70 (17 mm) microalloyed X70 pipe steel are characterized using Rietveld refinement (a.k.a. quantitative X-ray diffraction (QXRD)), inductively coupled plasma mass spectrometry (ICP), and energy-dispersive X-ray spectroscopy (EDX) analyses. Rietveld refinement is done to quantify the
[...] Read more.
Precipitates in thin-walled (11 mm) and thick-walled X70 (17 mm) microalloyed X70 pipe steel are characterized using Rietveld refinement (a.k.a. quantitative X-ray diffraction (QXRD)), inductively coupled plasma mass spectrometry (ICP), and energy-dispersive X-ray spectroscopy (EDX) analyses. Rietveld refinement is done to quantify the relative abundance, compositions, and size distribution of the precipitates. EDX and ICP analyses are undertaken to confirm Rietveld refinement analysis. The volume fraction of large precipitates (1 to 4 μm—mainly TiN rich precipitates) is determined to be twice as high in the thick-walled X70 steel (0.07%). Nano-sized precipitates (<20 nm) in the thin-walled steel exhibit a higher volume fraction (0.113%) than in the thick-walled steel (0.064%). The compositions of the nano-sized precipitates are similar for both steels. Full article
(This article belongs to the Special Issue Rietveld Refinement in the Characterization of Crystalline Materials)
Figures

Figure 1

Open AccessArticle The Rietveld Refinement in the EXPO Software: A Powerful Tool at the End of the Elaborate Crystal Structure Solution Pathway
Crystals 2018, 8(5), 203; https://doi.org/10.3390/cryst8050203
Received: 13 April 2018 / Revised: 30 April 2018 / Accepted: 2 May 2018 / Published: 4 May 2018
PDF Full-text (1271 KB) | HTML Full-text | XML Full-text
Abstract
The Rietveld method is the most reliable and powerful tool for refining crystal structure when powder diffraction data are available. It requires that the structure model to be adjusted is as close as possible to the true structure. The Rietveld method usually represents
[...] Read more.
The Rietveld method is the most reliable and powerful tool for refining crystal structure when powder diffraction data are available. It requires that the structure model to be adjusted is as close as possible to the true structure. The Rietveld method usually represents the final step of the powder solution process, in particular when a new structure is going to be determined and published. EXPO is a software able to execute all the steps of the solution process in a mostly automatic way, by starting from the chemical formula and the experimental diffraction pattern, passing through computational methods for locating the structure model and optimizing it, and ending to the Rietveld refinement. In this contribution, we present the most recent solution strategies in EXPO, both in reciprocal and direct space, aiming at obtaining models suitable to be refined by the Rietveld method. Examples of Rietveld refinements are described, whose results are related to different solution procedures and types of compounds (organic and inorganic). Full article
(This article belongs to the Special Issue Rietveld Refinement in the Characterization of Crystalline Materials)
Figures

Figure 1

Open AccessArticle Error Analysis and Correction for Quantitative Phase Analysis Based on Rietveld-Internal Standard Method: Whether the Minor Phases Can Be Ignored?
Crystals 2018, 8(3), 110; https://doi.org/10.3390/cryst8030110
Received: 26 December 2017 / Revised: 14 February 2018 / Accepted: 19 February 2018 / Published: 27 February 2018
PDF Full-text (2011 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The Rietveld-internal standard method for Bragg-Brentano reflection geometry (θ/2θ) X-ray diffraction (XRD) patterns is implemented to determine the amorphous phase content. The effect of some minor phases on quantitative accuracy is assessed. The numerical simulation analysis of errors and
[...] Read more.
The Rietveld-internal standard method for Bragg-Brentano reflection geometry (θ/2θ) X-ray diffraction (XRD) patterns is implemented to determine the amorphous phase content. The effect of some minor phases on quantitative accuracy is assessed. The numerical simulation analysis of errors and the related corrections are discussed. The results reveal that high purity of crystalline phases in the standard must be strictly ensured. The minor amorphous or non-quantified crystalline phases exert significant effect on the quantitative accuracy, even with less than 2 wt% if ignored. The error levels are evaluated by numerical simulation analysis and the corresponding error-accepted zone is suggested. To eliminate such error, a corrected equation is proposed. When the adding standard happens to be present in sample, it should be also carefully dealt with even in low amounts. Based on that ignorance, the absolute and relative error equations (ΔAE, ΔRE) are derived, as proposed. The conditions for high quantitative accuracy of original equation is strictly satisfied with a lower amount of standard phase present in sample, less than 2 wt%, and a higher dosage of internal standard, larger than 20 wt%. The corrected equation to eliminate such quantitative error is suggested. Full article
(This article belongs to the Special Issue Rietveld Refinement in the Characterization of Crystalline Materials)
Figures

Graphical abstract

Back to Top