X-ray diffraction (XRD) characterization of Si powder was carried out using synchrotron and laboratory sources. Microstructural (size-strain) analyses of XRD patterns were carried out using the Rietveld refinement method. Experimentally observed super-Lorentzian shapes of the XRD peaks of Si powder were examined using multimodal profile fitting and bimodal model was found to be adequate. The two components obtained using a bimodal approach are referred as narrow and broad profiles based on their estimated relative peak widths. Peak shapes of crystallite size-dependent parts of narrow and broad profiles were found to be almost Gaussian and Lorentzian in nature, respectively. The simultaneous presence of such peak shapes corresponding to a bimodal microstructure is uncommon in literature. Therefore, in order to explore the role of different natures of XRD peak shapes (size dependent) of the bimodal profiles of Si, detailed microstructural analysis was carried out using the complementary method of whole powder pattern modeling (WPPM) and found to be related to the variance of crystallites' size distribution. Additionally, the effect of instrument resolution (laboratory and synchrotron sources) on the microstructural parameters was also studied. Scanning and transmission electron microscopy were used to characterize the morphology of Si powder and correlate with the microstructural findings of XRD methods.

The values of the signal-to-noise ratio are determined, at which the method of processing X-ray diffraction data reveals reflections with intensity less than the noise component of the background. The possibilities of the method are demonstrated on weak reflections of α-quartz. The method of processing X-ray diffraction data makes it possible to increase the possibilities of X-ray phase analysis in determining the qualitative phase composition of multiphase materials with a small (down to 0.1 wt.%) content of several (up to eight) phases.

The crystal structure of brimonidine hydrogen tartrate has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Brimonidine hydrogen tartrate crystallizes in space group P21 (#4) with a = 7.56032(2), b = 7.35278(2), c = 30.10149(9) Å, β = 90.1992(2)°, V = 1673.312(10) Å3, and Z = 4 at 295 K. The crystal structure consists of alternating layers of cations and anions parallel to the ab-plane. Each of the hydrogen tartrate anions is linked to itself by very strong charge-assisted O–H⋯O hydrogen bonds into chains along the a-axis. Each hydroxyl group of each tartrate acts as a donor in an O–H⋯O or O–H⋯N hydrogen bond. One of these is intramolecular, but the other three are intermolecular. These hydrogen bonds link the hydrogen tartrate anions into layers parallel to the ab-plane and also link the anion–cation layers. The protonated N atoms act as donors in N–H⋯O or N–H⋯N hydrogen bonds to the carboxyl groups of the tartrates and to a ring nitrogen atom. These link the cations and anions, as well as providing cation–cation links. The amino N atoms of the cations form N–H⋯O hydrogen bonds to hydroxyl groups of the anions. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®)

A monoclinic C form of rilpivirine hydrochloride, (N6H19C22)Cl, has been obtained and characterized using solid-state 15N, 13C, and 35Cl NMR spectroscopy and multitemperature synchrotron X-ray powder diffraction. The title compound crystallizes in the monoclinic system (space group C2/c, #15) at both room (295.0(2) K) and low (100.0(2) K) temperatures. At room temperature, the following parameters are a = 19.43051(3), b = 13.09431(14), c = 17.10254(18) Å, β = 109.3937(7), V = 4104.48(9) Å3, and Z = 8. The folded molecular conformation of the cation is similar with that of free base rilpivirine with the exception of cyanovinyl group disposition. The anion links cations to infinite chains parallel to the crystallographic c axis using N–H⋯Cl bonds where both amino groups and the protonated pyrimidine ring take part in the H-bonding. The powder patterns have been submitted to the ICDD for inclusion in the Powder Diffraction File™ (PDF®).

The crystal structure of nintedanib esylate hemihydrate was refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Nintedanib esylate hemihydrate crystallizes in space group P-1 (#2) with a = 11.5137(1), b = 16.3208(4), c = 19.1780(5) Å, α = 69.0259(12), β = 84.4955(8), γ = 89.8319(6)°, V = 3347.57(3) Å3, and Z = 4 at 295 K. Hydrogen bonds are prominent in the crystal structure. The water molecule forms two medium-strength O–H⋯O hydrogen bonds to one of the esylate anions. The protonated nitrogen atom in each cation forms a N–H⋯O hydrogen bond to an esylate anion. The ring N–H groups form strong intramolecular N–H⋯O hydrogen bonds to carbonyl groups. The ring N–H groups form intramolecular N–H⋯O hydrogen bonds to esylate anions. Many C–H⋅⋅⋅O hydrogen bonds (and one C–H⋯N hydrogen bond), with aromatic C–H, methylene groups and methyl groups as donors, are present. The hydrogen bonding patterns of the two cations differ considerably. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®)

Leucites are tetrahedrally coordinated silicate framework structures with some of the silicon framework cations that are partially replaced by divalent or trivalent cations. These structures have general formulae A2BSi5O12 and ACSi2O6, where A is a monovalent alkali metal cation, B is a divalent cation, and C is a trivalent cation. There are also leucite analogs with analogous tetrahedrally coordinated germanate framework structures. These have general formulae A2BGe5O12 and ACGe2O6. In this paper, the Rietveld refinements of three synthetic Ge-leucite analogs with stoichiometries of AAlGe2O6 (A = K, Rb, Cs) are discussed. KAlGe2O6 is I41/a tetragonal and is isostructural with KAlSi2O6. RbAlGe2O6 and CsAlGe2O6 are $I\bar{4}3d$ cubic and are isostructural with KBSi2O6.

The crystal structure of alectinib hydrochloride has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Alectinib hydrochloride crystallizes in space group P21/n (#14) with the following parameters: a = 12.67477(7), b = 10.44076(5), c = 20.38501(12) Å, β = 93.1438(7)°, V = 2693.574(18) Å3, and Z = 4 at 295 K. The crystal structure consists of stacks of molecules along the b-axis, and the stacks contain chains of strong N–H⋯Cl hydrogen bonds. One density functional theory calculation moved a proton from an N atom to the Cl, but another calculation yielded a more chemically reasonable result. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®)

The crystal structure of valbenazine has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Valbenazine crystallizes in space group P212121 (#19) with a = 5.260267(17), b = 17.77028(7), c = 26.16427(9) Å, V = 2445.742(11) Å3, and Z = 4 at 295 K. The crystal structure consists of discrete molecules and the mean plane of the molecules is approximately (8,−2,15). There are no obvious strong intermolecular interactions. There is only one weak classical hydrogen bond in the structure, from the amino group to the ether oxygen atom. Two intramolecular and one intermolecular C–H⋯O hydrogen bonds also contribute to the lattice energy. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®)