The structure, powder diffraction patterns and bandgap measurements of a series of manganese- and tungsten-containing alkaline-earth double perovskites (CaxSr2−x)MnWO6 (x = 0.25, 0.5, 0.75, 1.5, 1.75) have been investigated. Powder X-ray diffraction patterns of this series of compounds measured at room temperature have been submitted to be included in the Powder Diffraction File (PDF). These compounds crystallize in monoclinic space group P21/n (No.14). From (Ca1.75 Sr0.25)MnWO6 to (Ca0.25Sr1.75)MnWO6, lattice parameters a range from 5.6729(2) Å to 5.6774(4) Å, b from 5.5160(2) Å to 5.6638(4) Å, c from 7.8741(3) Å to 8.0051(4) Å, V from 240.39(2) Å3 to 257.410(12) Å3, and Z = 2. These compounds are pseudo-tetragonal. They all consist of distorted MnO6 and WO6 octahedra with rotational mismatch angles and tilt angles with respect to each other. For (CaxSr2−x)MnWO6, as x increases, the mismatch angles for MnO6 octahedra increase from 7.96 (6)° to 13.12(8)° and from 9.28(7)° to 14.87(9)° for WO6 octahedra. Correspondingly, the tilt angles range from 11.60(15)° to 14.20(3)° for MnO6, and from 13.34(2)° to 16.35(3)° for WO6. Bandgap measurements suggest that these compounds to be direct-allowed semiconductors with bandgaps ranging from 1.5 to 2.5 eV, indicating that members of (CaxSr2−x)MnWO6 are potential photocatalysts and photovoltaic materials that absorb visible light of the solar spectrum.

This paper aims to explore the influence of solvent effects on the crystal habit of venlafaxine hydrochloride using the modified attachment energy (MAE) model by molecular dynamics (MD) simulation. Solvent effects were investigated based on the different morphologies of venlafaxine hydrochloride acquired by simulation and experimental technology from the solvents of isopropanol, dimethyl sulfoxide, and acetonitrile. Firstly, morphologically dominant crystal faces were obtained through the prediction of crystal habit in vacuum by the attachment energy (AE) model. Subsequently, the MAEs were calculated by the MD simulation to modify the crystal shapes in a real solvent environment, and the simulation results were in agreement with the experimental ones. Meanwhile, in order to have a better understanding of the solvent effects, the surface structure was introduced to analyze the solvent adsorption behaviors. The results show that the crystal habits of venlafaxine hydrochloride are affected by the combination of the AE and surface structures. Finally, the flowability of the obtained crystal powders from different solvents was investigated by measurement and analysis of the angle of repose and compressibility. The above results verify that the physical properties are closely related to the morphologies of the crystals.

The crystal structure of merimepodib has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Merimepodib crystallizes in space group P212121 (#19) with a = 4.60827(3), b = 12.30400(14), c = 37.9583(4) Å, V = 2152.241(20) Å3, and Z = 4. The crystal structure is dominated by two chains of N–H⋯O hydrogen bonds along the a-axis. The solid-state conformation has a similar general shape to the minimum-energy conformation, but different orientations of several of the rings. The differences indicate that intermolecular interactions are important in determining the solid-state conformation. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

The crystal structure of baricitinib has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Baricitinib crystallizes in space group I2/a (#15) with a = 11.81128(11), b = 7.06724(6), c = 42.5293(3) Å, β = 91.9280(4)°, V = 3548.05(5) Å3, and Z = 8. The crystal structure is characterized by hydrogen-bonded double layers parallel to the ab-planes. The dimers form a graph set R2,2(8). The sulfone ends of the molecules reside in the interlayer regions. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

The crystal structure of fulvestrant hydrate (ethyl acetate) has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. This solvate of fulvestrant crystallizes in space group R3 (#146) with a = 23.39188(16), c = 16.50885(13) Å, V = 7823.08(7) Å3, and Z = 9. The crystal structure is composed of triangular hydrogen-bonded chains of molecules around one of the threefold axes. The fluorinated ends of the molecules cluster around another threefold axis. Voids around a threefold axis occupy 8.1% of the unit cell volume, and are partially occupied by the water and ethyl acetate molecules. Both hydroxyl groups act as donors in O–H⋯O hydrogen bonds. These H-bonds form a large ring. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

X-ray powder diffraction data, unit-cell parameters, and space group for the topiroxostat form II, C13H8N6, are reported [a = 7.344(9) Å, b = 12.946(7) Å, c = 12.133(5) Å, β = 96.99(3)°, V = 1145.2(4) Å3, Z = 4, and space group P21/c]. The topiroxostat monohydrate, C13H8N6·H2O, crystallized in a triclinic system and unit-cell parameters are also reported [a = 7.422(9) Å, b = 8.552(1) Å, c = 11.193(5) Å, α = 74.85(1)°, β = 81.17(1)°, γ = 66.29(1)°, V = 627.0(6) Å3, Z = 2, and space group P-1]. In each case, all measured lines were indexed and are consistent with the corresponding space group. The single-crystal data of two solid-state forms of topiroxostat are also reported, respectively [a = 7.346(2) Å, b = 12.955(2) Å, c = 12.130(7) Å, β = 96.91(6)°, V = 1146.1(3) Å3, Z = 4, and space group P21/c] and [a = 7.418(6) Å, b = 8.532(8) Å, c = 11.183(9) Å, α = 74.807(1) °, β = 81.13(1)°, γ = 66.32(1) °, V = 624.7(6) Å3, Z = 2, and space group P-1]. The experimental powder diffraction pattern has been well matched with the simulated pattern derived from the single-crystal data.

The crystal structure of anhydrous alfuzosin hydrochloride has been solved and refined using laboratory X-ray powder diffraction data and optimized using density functional theory techniques. Anhydrous alfuzosin hydrochloride crystallizes in space group P-1 with a = 9.3214(16), b = 9.3997(29), c = 12.6172(64) Å, α = 107.993(11), β = 100.386(9), γ = 90.229(6)°, V = 1032.1(10) Å3, and Z = 2 at ambient conditions. Thermal expansion is anisotropic, being 8× larger in the c-direction than in the other two. The crystal structure is characterized by a stack of planar fused rings along the b-axis, and layers of the more-corrugated portion of the molecule parallel to the ab-plane. There are two strong N–H⋯Cl hydrogen bonds, as well as seven C-H⋯Cl hydrogen bonds. The powder patterns have been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

The first Pan-African Conference on Crystallography, PCCr1, was held in Dschang, Cameroon in 2016. This highly successful meeting attracted 192 participants from 32 countries, including 20 African countries. PCCr2 followed in 2019, with over 200 participants from 35 countries. This was a joint meeting with AfLS and was hosted in Accra, Ghana. PPCCr3 was scheduled to take place in Nairobi, Kenya in 2021. Unfortunately, due to the pandemic, this meeting had to be postponed. The Steering Committee of the African Crystallographic Association, along with the Local Organizing Committee of PCCr3, decided to hold an online meeting in order to continue the momentum and sense of community generated during the first two PCCr meetings. ePCCr was, therefore, organized.