Powder Diffraction Patterns Research Articles

Verification of a method for determining the degree of crystallinity using experimental and computer-generated powder diffraction patterns. Corrigendum

An erroneous equation and some values of related parameters in the paper by Toraya [J. Appl. Cryst. (2023), 56, 1751–1763] are corrected.

Crystal structure and Hirshfeld surface analysis of pinaverium bromide dihydrate

In the present study, we have discovered and identified a new crystalline form of pinaverium bromide, pinaverium bromide dihydrate (C26H41BrNO4⋅Br⋅2H2O), whose single crystals can be obtained by recrystallization from a mixture of water and acetonitrile at room temperature. The obtained crystals were characterized by X-ray single-crystal diffraction, and their crystal structure was also solved based on X-ray single-crystal diffraction data. The results show that the final pinaverium bromide dihydrate model contains an asymmetric unit of one pinaverium bromide (C26H41Br2NO4) molecule and two water molecules that combine with the bromine ion through O–H⋯O and O–H⋯Br hydrogen bonds. Then, the adjacent pinaverium bromide dihydrates are linked by O–H⋯O, O–H⋯Br, and C–H⋯O hydrogen bonds. On the other hand, the experimentally obtained X-ray powder diffraction pattern is in good agreement with the simulated diffraction pattern from their single-crystal data, confirming the correctness of the crystal structure. Hirshfeld surface analysis was employed to understand and visualize the packing patterns, indicating that the H⋯H interaction is the main acting force in the crystal stacking of pinaverium bromide dihydrate.

Effect of solvent in the solvothermal synthesis of nickel(II)-terephthalate complex

This research aims to replace the use of dimethylformamide (DMF) with a greener solvent in the solvothermal synthesis of nickel(II)-terephthalate complex. Effect of solvent on the crystallinity degree, thermal stability, and band gap energy of the synthesized complex are also studied. The synthesis was carried out using solvothermal method at 150 0C for 10 hours with a Ni(II) : terephthalate acid mol ratio of 1:1 in several H2O:DMF solvent compositions (1:0; 1:1; and 0:1). The precipitated products underwent characterization using ATR-IR, P-XRD, SEM, TGA, Surface Area Analyzer, and UV-DRS. Findings revealed the successful formation of the Ni(II)-terephthalate complex using three different solvent compositions (H2O/DMF = 1:0, 1:1, and 0:1). This suggests that the complex can be synthesized using more environmentally friendly solvents, potentially reducing or substituting the use of DMF solvent. However, the solvent affects the characteristics of the synthesized complex, in which green block microcrystalline solid was obtained when using water as the solvent, meanwhile green aggregates with lower crystallinity degree was precipitated out when using DMF or H2O-DMF. The Ni(II)-terephthalate complexes obtained from the H2O and H2O-DMF solvents are different to that of from the DMF solvent, but they both has identical powder diffraction pattern with previously reported compound of [Ni3(OH)2(C8H4O4)2(H2O)4].2H2O. Furthermore, the use of water as the solvent increase the crystallinity degree and thermal stability of the complex but the band gap energy of the synthesized Ni(II)-terephthalate complex compared to that of obtained from the DMF solvents.

Energy trapping to substitutional and charge compensation defects in persistent luminescent BaAl2O4:Tb3+

The holistic approach of the photoluminescence (PL), thermoluminescence (TL), and persistent luminescence properties at room temperature of BaAl2O4:Tb3+ were investigated in detail using a wide range of techniques. Materials were obtained using a solution combustion synthesis. The x-ray powder diffraction patterns of nondoped and Tb3+ doped BaAl2O4 indicated the hexagonal phase, and a Tb4O7 solid solution was observed at 4 and 5 mol% Tb doped aluminate. X-ray photoelectron spectroscopy revealed that Ba occupied one site and that Tb ions occupied this site as Tb3+ as well as TbIV. PL emission in blue, green, and red was observed under an excitation at 228 nm, that originated from the interconfigurational 4f8–4f75d1 transitions of Tb3+. Time-of-flight secondary ion mass spectroscopy, UV–vis diffuse reflectance, and PL revealed the presence of a Cr3+ impurity. The 0.5 mol% Tb3+ doped BaAl2O4 exhibited a strong TL band at 354, 437 and 598 K, which were attributed to the traps formed by Tb3+ doping and subsequent O2− charge compensation. A persistent luminescence mechanism was constructed for the Tb3+ doped BaAl2O4. After the energy was stored in thermally liberated Tb3+ in the Ba2+ substitution sites and charge compensation defects, the Tb3+ was the source of the continuous luminescence.

Energy band gap tuning of Ba-Ca hexagonal ferrite by Dy3+ ion substitution (0 ≤ x ≤ 0.2) to improve spectral, structural, dielectric and photocatalytic properties

In the present study, Dy3+ substituted M-type Ba0.5Ca0.5DyxFe12-xO19 (0.00 ≤ x ≤ 0.20) hexagonal ferrites were synthesized using sol-gel auto-combustion method with lemon extract as a fuel. The single hexaferrite phase with space group P63/mmc is revealed by the X-ray powder diffraction (XRD) patterns. The Field emission scanning electron microscopy (FESEM) exhibits the agglomeration of nanoplates with vacancies at some places. Energy dispersive X-ray photoelectron spectroscopy (EDAX) mapping confirmed the presence of Ba, Ca, Fe, O, and Dy in the hexaferrite. Fourier Transform Infrared (FTIR) spectroscopy exhibits two characteristic bands at 579 and 429 cm−1 corresponding to tetrahedral and octahedral metal ions-oxygen stretching, revealing the occurrence of the ferrite phase. The optical energy band gap calculated using the Tauc plots was found to increase with the increase in dysprosium substitution to fall within the range of 2.8–3.5 eV. The Raman spectra confirmed the Raman vibration modes and M-type structures of hexagonal ferrites (HFs). The dielectric constant values drop rapidly with increasing frequency up to a few KHz and then gradually for the further higher frequencies. The occurrence of Ba and Ca with 2+, while Dy, and Fe with 3+ oxidation states is confirmed using X-ray photoelectron spectroscopy (XPS). The HFs exhibit remarkable efficiency by degrading the Reactive Brown dye to 99.3 % in just 15 min, equivalent to a high degradation reaction rate constant (k) value of up to 0.0396 min−1. Consequently, the catalyst shows promising potential for environmental remediation.

Magnetic properties and linear negative magnetocapacitance in rutile like LiFe2SbO6

Abstract We report the high-temperature magnetic ordering and the observation of linear negative magnetocapacitance mediated by a low-temperature magnetic phase crossover in the compound LiFe2SbO6. The combined observations of the absence of a second harmonic generation (SHG) signal, and Rietveld refinements of X-ray and neutron powder diffraction (NPD) patterns of the sample confirm that LiFe2SbO6 crystalizes in a centrosymmetric Pnnm structure. The DC magnetization measurements reveal that an antiferromagnetic ordering sets in at high temperature (TN= 850). The magnetic anomaly in the DC magnetization at a lower temperature T = 13 K, is corroborated by AC susceptibility and the specific heat measurements. We observe a linear negative magnetocapacitance below T = 13 K, demonstrating an indirect magneto-dielectric coupling. Further, the neutron powder diffraction study reveals a collinear antiferromagnetic ordering with a wavevector k = (0, 0, 0).

Establishing Composition of Solid Solution Based on Single Crystal and Powder X-ray Measurement: The Case of Halogenated Bismuth(III) Complexes with Acetophenone-4-methyl-3-thiosemicarbazone

New bismuth (III) complexes with acetophenone-4-methyl-3-thiosemicarbazone (L) and halogens (Cl and Br) in both bridging and terminal positions have been synthesized and structurally characterized using single-crystal X-ray diffraction. The pure complexes (Cl or Br) were found to be highly isostructural, which motivated our attempts to create solid solutions of these complexes. A series of such compounds was prepared using various procedures and stoichiometries. A method for determining the mutual concentrations of different halogens, based on the positions of selected peaks in powder diffraction patterns, was tested and compared with other methods.

Microwave-assisted synthesis of γ-alooh nanoflowers as an adsorbent for cadmium removal from domestic wastewater.

In this study, cadmium ions were effectively removed from domestic wastewaters using an adsorptive treatment strategy based on γ-AlOOH nanoflowers. A novel, rapid, and simple procedure was developed for the synthesis of the nanoflowers. Characterization studies were performed using X-ray powder diffraction patterns and scanning electron microscope images. The synthesized nanoflowers were utilized as adsorbent in the batch adsorption experiments. The influential parameters of the adsorption process were optimized, and a flame atomic absorption spectrophotometry (FAAS) system was used to determine maximum percent removal of cadmium ions. Matrix-matched calibration strategy, in which the calibration plot was developed in wastewater medium, was utilized for the accurate and precise quantification of cadmium in the effluent samples. The percentage removal efficiency values were calculated between 84 and 98% for different concentrations of cadmium ions in the wastewater samples. Equilibrium data was fitted to the four different linearization methods of the Langmuir isotherm model, as well as the Freundlich isotherm model and Elovich isotherm model. The best fitting was achieved for the Langmuir model with a high R2 value of 0.9956 and maximum adsorption capacity was calculated as 6.23mg/g.

FullProfAPP: a graphical user interface for the streamlined automation of powder diffraction data analysis

FullProfAPP is a software tool for data processing, refinement and visualization of large collections of powder diffraction patterns. Featuring an intuitive graphical user interface, it seamlessly facilitates a variety of tasks. These include conducting full-profile phase searches, sequential and high-throughput Rietveld refinements, and managing background (and peak) detection. FullProfAPP also provides convenient interaction with crystallographic databases and supports the visualization and export of high-quality pixel and vector graphics depicting the refinement results, among other functionalities. FullProfAPP wraps around the refinement program FullProf [Rodríguez-Carvajal (1993), Physica B, 192, 55–69] and offers the flexibility of user-defined workflows by accessing and editing FullProf's input files and triggering its execution as necessary. FullProfAPP is distributed as open-source software and is presently available for Windows and Linux operating systems.

Crystal Structure Determination from Powder Diffraction Patterns with Generative Machine Learning.

Powder X-ray diffraction (PXRD) is a cornerstone technique in materials characterization. However, complete structure determination from PXRD patterns alone remains time-consuming and is often intractable, especially for novel materials. Current machine learning (ML) approaches to PXRD analysis predict only a subset of the total information that comprises a crystal structure. We developed a pioneering generative ML model designed to solve crystal structures from real-world experimental PXRD data. In addition to strong performance on simulated diffraction patterns, we demonstrate full structure solutions over a large set of experimental diffraction patterns. Benchmarking our model, we predicted the structure for 134 experimental patterns from the RRUFF database and thousands of simulated patterns from the Materials Project on which our model achieves state-of-the-art 42 and 67% match rate, respectively. Further, we applied our model to determine the unreported structures of materials such as NaCu2P2, Ca2MnTeO6, ZrGe6Ni6, LuOF, and HoNdV2O8 from the Powder Diffraction File database. We extended this methodology to new materials created in our lab at high pressure with previously unsolved structures and found the new binary compounds Rh3Bi, RuBi2, and KBi3. We expect that our model will open avenues toward materials discovery under conditions which preclude single crystal growth and toward automated materials discovery pipelines, opening the door to new domains of chemistry.

Magnetic symmetries of terbium tetraboride (TbB4) revealed by resonant x-ray Bragg diffraction

A recent experimental study of TbB4 at a low temperature using resonant x-ray Bragg diffraction implies a magnetic symmetry not found in any other rare-earth tetraboride. The evidence for this assertion is a change in the intensity of a TbB4 Bragg spot on reversing the handedness (chirality) of the primary x-ray beam [R. Misawa, K. Arakawa, T. Yoshioka, H. Ueda, F. Iga, K. Tamasaku, Y. Tanaka, and T. Kimura, ]. It reveals a magnetic chiral signature in TbB4 that is forbidden in phases of rare-earth tetraborides known to date, as the previous magnetic symmetries are parity-time (PT) symmetric with anti-inversion present in the magnetic crystal class. Misawa appeal to a PT-symmetric diffraction pattern to interpret their interesting diffraction patterns. In addition to the use of symmetry that does not permit a chiral signature, calculated patterns impose cylindrical symmetry on Tb sites with no justification. We review magnetic symmetries for TbB4 consistent with a published neutron powder diffraction pattern and susceptibility measurements. On the basis of this information, noncollinear antiferromagnetic order exists below a temperature ≈44 K with no ferromagnetic component. Our symmetry-informed patterns encapsulate Tb electronic degrees of freedom in terms of multipoles consistent with established sum rules for dichroic signals. The investigated symmetry templates are noncentrosymmetric, noncollinear antiferromagnetic constructions with propagation vector k=(0,0,0). An inferred chiral signature for a parity-even absorption event has an interesting composition. There is the anticipated product of Tb axial dipoles and chargelike quadrupoles (from Templeton-Templeton scattering). Beyond this contribution, though, symmetry allows a product of dipoles in the chiral signature. A predicted change in the intensity of a Bragg spot with rotation of the crystal about the reflection vector (an azimuthal angle scan) can be tested in future experiments. Likewise contributions to Bragg diffraction patterns from Tb anapoles and higher-order Dirac multipoles. Published by the American Physical Society 2024

Karlleuite Ca2MnO4 – a first mineral with the Ruddlesden-Popper type structure from Bellerberg volcano, Germany

AbstractKarlleuite, ideally Ca2MnO4, is a newly approved accessory mineral found in the xenolith sample within the basaltic lava from the Caspar quarry, Bellerberg volcano, Eifel, Germany. It usually occurs as thin tabular/plate crystals, which range from 40 to 80 μm in diameter, and is associated with other members of the perovskite supergroup such as srebrodolskite, brownmillerite, sharyginite, perovskite, and lakargiite distributed within rock-forming minerals represented by reinhardbraunsite, fluorellestadite, fluorapatite, larnite, gehlenite, and several hydrated Ca aluminosilicates. Karlleuite crystals are brown with sub-metallic lustre, a light brown streak, and a good cleavage along (001). It is non-fluorescent, brittle and has an uneven fracture, a Mohs hardness of 3.5 and calculated density Dx = 3.79 g/cm3. The empirical formula of the holotype karlleuite calculated based on O = 4 atoms per formula is (Ca1.97Ce3+0.06)2.03(Mn4 + 0.39Ti0.36Fe3+0.19Al0.09)1.03O4, which shows that it is a multicomponent phase characterised by various substituents at the octahedral site. Karlleuite is tetragonal I4/mmm (no. 139), with a = 3.7683(2) Å, c = 11.9893(8) Å, V = 170.254(17) Å3, and Z = 2. The calculated strongest lines in the X-ray powder diffraction pattern are [d in Å (I) hkl]: 5.995 (43), 2.742 (100), 2.665 (91), 2.023 (25), 1.998 (28), 1.884 (61), 1.553 (38), 1.371 (24). The new mineral is the first natural phase which exhibits a first order of Ruddlesden-Popper type structure, which indicates a modular nature and consists of Ca(Mn, Ti, Fe, Al)O3 perovskite layers, packed between CaO rock-salt layers arranged along the c-axis. Raman spectroscopy supports the interpretation of the chemical and structural data. Mineral association, structural data, as well as the study of the synthetic Ca-Mn-O system suggest that karlleuite could form under high-temperature conditions, above 1000˚C.

Importance of powder diffraction raw data archival in a curated database for materials science applications.

In recent years, there is a significant interest from the crystallographic and materials science communities to have access to raw diffraction data. The effort in archiving raw data for access by the user community is spearheaded by the International Union of Crystallography (IUCr) Committee on Data. In materials science, where powder diffraction is extensively used, the challenge in archiving raw data is different to that from single crystal data, owing to the very nature of the contributions involved. Powder diffraction (X-ray or neutron) data consist of contributions from the material under study as well as instrument specific parameters. Having raw powder diffraction data can be essential in cases of analysing materials with poor crystallinity, disorder, micro structure (size/strain) etc. Here, the initiative and progress made by the International Centre for Diffraction Data (ICDDR) in archiving powder X-ray diffraction raw data in the Powder Diffraction FileTM (PDFR) database is outlined. The upcoming 2025 release of the PDF-5+ database will have more than 20 800 raw powder diffraction patterns that are available for reference.

Preparation of SrVO3 by annealing of Sr2V2O7 in a reducing atmosphere

This study focuses on the synthesis of SrVO3 through the reduction of Sr2V2O7 by annealing in a reducing atmosphere. The effects of annealing temperature and annealing duration on Sr2V2O7 were investigated. The X-ray powder diffraction pattern showed that stoichiometric changes to Sr2V2O7 were achieved only at an elevated annealing temperature of 1000 °C in a reducing atmosphere, and that the desired SrVO3 was obtained only after 144 h of annealing. Further investigation of SrVO3 was performed using X-ray photoelectron spectroscopy, which confirmed that the reduction of V5+ found in Sr2V2O7 to V4+ found in SrVO3 was achieved.

DENNIS: a design and analysis tool for dynamic material x-ray diffraction experiments

We present DENNIS (Diffraction Experiment desigN and aNalysiS): a graphical software tool useful for the design and analysis of dynamic x-ray diffraction experiments, such as those performed on the Z Pulsed Power Facility, Thor Pulsed Power Generator, and Dynamic Compression Sector (DCS) of the Advanced Photon Source. DENNIS provides rapid powder and single-crystal diffraction pattern predictions and powder diffraction pattern image integration in three-dimensional geometries. Additional features include crystallographic information file reading, image processing, and synthetic diffraction pattern image generation. We overview the software's capabilities, detail the prediction and integration methodologies, and provide example implementations on Z and DCS experiments.

Crystallographic phase identifier of a convolutional self-attention neural network (CPICANN) on powder diffraction patterns.

Spectroscopic data, particularly diffraction data, are essential for materials characterization due to their comprehensive crystallographic information. The current crystallographic phase identification, however, is very time consuming. To address this challenge, we have developed a real-time crystallographic phase identifier based on a convolutional self-attention neural network (CPICANN). Trained on 692 190 simulated powder X-ray diffraction (XRD) patterns from 23 073 distinct inorganic crystallographic information files, CPICANN demonstrates superior phase-identification power. Single-phase identification on simulated XRD patterns yields 98.5 and 87.5% accuracies with and without elemental information, respectively, outperforming JADE software (68.2 and 38.7%, respectively). Bi-phase identification on simulated XRD patterns achieves 84.2 and 51.5% accuracies, respectively. In experimental settings, CPICANN achieves an 80% identification accuracy, surpassing JADE software (61%). Integration of CPICANN into XRD refinement software will significantly advance the cutting-edge technology in XRD materials characterization.

Zvěstovite-(Fe), Ag6(Ag4Fe2)As4S13, a new member of the tetrahedrite group from the Ulatayskoe Ag–Cu–Co occurrence, eastern Siberia, Russia

Abstract. The new mineral zvěstovite-(Fe), ideally Ag6(Ag4Fe2)As4S13, has been found in the small abandoned Ulatayskoe Ag–Cu–Co occurrence, Ovyurskiy District, Tuva Republic, eastern Siberia, Russia. It occurs as anhedral grains, up to 1 × 0.4 mm in size but usually much smaller, closely intergrown with native silver, in Mg-bearing siderite–quartz gangue. Other associated minerals include acanthite, cobaltite, As-rich members of the tetrahedrite group (kenoargentotennantite-(Fe), tennantite-(Zn), zvěstovite-(Zn)), gersdorffite, jalpaite, krutovite, löllingite, pearceite, safflorite, skutterudite, Br-bearing chlorargyrite, malachite, and muscovite. Zvěstovite-(Fe) is iron black and opaque and has a black streak and metallic lustre. It is brittle and has a conchoidal fracture. No cleavage or parting is observed. The Vickers micro-indentation hardness (Vickers hardness number, VHN; 25 g load) is 169 kg mm−2 (range of 149–187 kg mm−2, n=4), corresponding to a Mohs hardness of 3–3.5. The calculated density is 4.979 g cm−3. In reflected light, zvěstovite-(Fe) is light grey with a greenish tint and isotropic. Internal reflections are ubiquitous and deep red in colour. The reflectance values for wavelengths recommended by the Commission on Ore Mineralogy of the International Mineralogical Association are (R, %): 32.5 (470 nm), 31.1 (546 nm), 30.1 (589 nm), and 28.8 (650 nm). The chemical composition (wt %, electron microprobe data, mean of eight spot analyses) is as follows: Cu 1.81, Ag 56.02, Fe 4.60, Zn 0.01, As 13.85, Sb 2.63, S 21.50, total 100.42. The empirical formula, calculated on the basis of 16 atoms per formula unit, is Ag9.93Cu0.54Fe1.58As3.54Sb0.41S12.83. Zvěstovite-(Fe) is cubic and has a space group of I4‾3m, with a=10.8601(3), V=1280.86(11) Å3, and Z=2. The strongest lines of the X-ray powder diffraction pattern (d, Å (I, %) hkl) are 7.68 (11) 110, 3.136 (100) 222, 2.717 (12) 400, 1.984 (8) 521, 1.921 (23) 440, and 1.638 (11) 622. The crystal structure of zvěstovite-(Fe) was refined to R1=0.0551 for 400 unique reflections with Fo>4σ (Fo). The possible ordering of the split M(2) sites is discussed. The new mineral is the Fe isotype of zvěstovite-(Zn). Both these minerals form the zvěstovite series within the tetrahedrite group.

Enhanced Magnetic and Dielectric Properties of YFeO3 Ceramics via Formation of Solid‐Solution with Sr2Bi4Ti5O18 and ZnSnO3 Oxides

In the present investigation, magnetic and dielectric properties of solid‐solution formed between the YFeO3 with the similar crystal structure of other oxide materials are focused on. Orthorhombic crystal structure of YFeO3 (YFO), Sr2Bi4Ti5O18 (SBT), and ZnSnO3 (ZS) nanomaterials are considered to prepare the solid solutions at 1150 °C/3 h. YFO and solid solutions exhibit the orthorhombic crystal structure, which is conformed through Rietveld refinement using X‐Ray powder diffraction pattern. The decreased average grain size is observed for the solid solution (3.0 μm for YFO and ZS and 2.6 μm for YFO and SBT) when compared to YFO (3.4 μm) through scanning electron microscopy. Oxidation state of each atom/ion/element present in the YFO and solid solutions are conformed through X‐Ray photoelectron spectroscopy studies. The solid solution formed between the YFO and SBT exhibits high magnetization value (2.92 emu g−1) and high coercive filed (67.5 Oe) when compared to solid solution formed between the YFO and ZS (magnetization value = 2.48 emu g−1, and coercive filed = 46.4 Oe) and YFO (magnetization value = 1.91 emu g−1, and coercive filed = 61.8 Oe). High dielectric permittivity (εr), low dielectric loss (tan δ), and low conductivity are observed for the solid solution formed between the YFO and SBT, when compared to other materials in this study.

Kvačekite, NiSbSe, a new selenide mineral from Bukov, Czech Republic

Abstract Kvačekite is a new mineral species discovered in a sample collected from the now abandoned Bukov uranium mine, western Moravia, Czech Republic. It occurs as rare anhedral grains, up to 15 μm in size, associated with nickeltyrrellite, tyrrellite, berzelianite, hakite-(Zn), hakite-(Cd), eucairite, clausthalite, and gold in calcite gangue. In reflected light, kvačekite is white with a faint yellowish shade; bireflectance, pleochroism and anisotropy are absent. Internal reflections were not observed. Reflectance values for the four COM wavelengths for kvačekite in air [R (%) (λ in nm)] are: 54.9 (470); 53.5 (546); 52.6 (589); and 52.2 (650). The empirical formula, based on electron-microprobe analyses (EPMA), is (Ni0.95Cu0.04Co0.03)Σ1.02Sb1.00(Se0.97S0.01)Σ0.98. The ideal formula is NiSbSe, which requires (in wt.%) Ni 22.63, Sb 46.93, Se 30.44, total 100.00. Kvačekite is cubic, P213, with unit-cell parameters a = 6.09013(13) Å, V = 225.881(15) Å3 and Z = 4. The strongest reflections in the X-ray powder diffraction pattern of synthetic kvačekite [d, Å (I) hkl] are: 3.0458 (11) 200; 2.7242 (100) 201, 210; 2.4867 (71) 211; 1.8632(39) 311; 1.6277(29) 321, 312; and 1.3290 (13) 421. Given the similarity with ullmannite, NiSbS, the crystal structure was refined from the powder X-ray diffraction data starting from those atomic coordinates using the synthetic analogue of kvačekite. Its crystal structure is formed by corner-sharing [NiSb3Se3] octahedra which form a three-dimensional network. The identity of the natural kvačekite and synthetic cubic NiSbSe were confirmed by a study of their chemical composition, reflectance measurements, Raman spectroscopy and electron back-scattered diffraction (EBSD) measurements on the mineral. Kvačekite is named after Milan Kvaček (1930–1993), a prominent Czech mineralogist. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2023-095).

Hen egg lysozyme polymorphs mediated by two ionic liquids during batch cooling crystallization

-Lysozyme batch cooling crystallization in the presence of two ionic liquids (ILs), 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), and 1,3-dimethylimidazolium iodide ([C1mim]I). Microscopic observation demonstrated that the crystal morphology with [C1mim]I is needle-like, while that with [C4mim]Cl and no ILs is plate-like. FTIR spectroscopy revealed that new peaks in the range of 1300–400 cm−1 occur with the case of adding [C1mim]I, meaning that the microstructure of lysozyme crystals changed. Raman spectroscopy and X-ray powder diffraction (XRD) pattern further confirmed that crystal forms of lysozyme with adding [C4mim]Cl and no ILs is completely different from that of adding [C1mim]I. Thermogravimetry (TG) and Differential Scanning Calorimeter (DSC) results indicated that addition of [C1mim]I delay the thermal deformation and degradation temperature of lysozyme crystals, suggesting that lysozyme crystals with [C1mim]I possesses higher thermal stability. The change in lysozyme crystal forms can be attributed to changes in interaction among lysozyme molecules and conformation in solution, leading to different assembly mode of molecules and formation of polymorphs. These findings could offer instructions for regulating lysozyme crystal forms and gaining initial insight into screening of potential ILs for developing polymorphs of the protein and other macromolecule crystals.