The structure of the anticancer drug carmustine (1,3-bis(2-chloroethyl)-1-nitrosourea, C5H9Cl2N3O2) was successfully determined from laboratory X-ray powder diffraction data recorded at 278 K and at 153 K. Carmustine crystallizes in the orthorhombic space group P212121 with Z = 4. The lattice parameters are a = 19.6935(2) Å, b = 9.8338(14) Å, c = 4.63542(6) Å, V = 897.71(2) ų at 153 K, and a = 19.8522(2) Å, b = 9.8843(15) Å, c = 4.69793(6) Å, V = 921.85(2) ų at 278 K. The Rietveld fits are very good, with low R-values and smooth difference curves of calculated and experimental powder data. The molecules form a one-dimensional hydrogen bond pattern. At room temperature, the investigated commercial sample of carmustine was amorphous.

Quaternary selenide, Pb4In2.6Bi3.4Se13 (x = 2.4 member of the Pb4(InxBi6-xSe13 solid solution), was synthesized by a solid-state technique, and its structure was determined using powder X-ray diffraction (XRD). Pb4In2.6Bi3.4Se13 crystallizes in the orthorhombic space group Pbam (No. 55) with Z = 4. Lattice parameters and calculated density were determined to be a = 22.152(5) Å, b = 27.454(5) Å, and c = 4.1354(6) Å, V = 2515.0(11) Å3, and Dx = 7.490 g cm−3. The structure consists of Z-shaped ribbon units and corner-shared infinite one-dimensional [InSe4]∞ chains running parallel to the c-axis. The chains and ribbons are further connected by Pb atoms to form a three-dimensional network. Pb atoms are situated in the center of bicapped trigonal prisms. The compound exhibits a semiconductor feature. The Seebeck coefficient of Pb4In2.6Bi3.4Se13 was found to be −180 μV K−1 at 295 K and −380 μV K−1 at 600 K. Combining the values of Seebeck coefficient, electrical conductivity, and thermal conductivity yield a figure of merit, ZT, of about 0.175 at 700 K. The powder XRD pattern of Pb4In2.6Bi3.4Se13 was also determined.

The direct derivation (DD) method is a technique for quantitative phase analysis (QPA). It can be characterized by the use of the total sums of scattered/diffracted intensities from individual components as the observed data. The crystal structure parameters are required when we calculate the intensities of reflections or diffraction patterns. Intensity can, however, be calculated only with the chemical composition data if it is not of individual reflections but of a total sum of diffracted/scattered intensities for that material. Furthermore, it can be given in a form of the scattered intensity per unit weight. Therefore, we can calculate the weight proportion of a component material by dividing the total sum of observed scattered/diffracted intensities by the scattered intensity per unit weight. The chemical composition data of samples under investigation are known in almost all cases at the stage of QPA. Thus, a technical problem is how to separate the observed diffraction pattern of a mixture into individual component patterns. Various pattern decomposition techniques currently available can be used for separating the pattern of a mixture. In this report, the theoretical background of the DD method and various techniques for pattern decompositions are reviewed along with the examples of applications.

The application of continuous-scan integration to collect X-ray diffraction data with a Si strip X-ray detector (CSI-SSXD) introduces additional effects on the peak shift and deformation of peak shape caused by the equatorial aberration. A deconvolutional method to correct the effects of equatorial aberration in CSI-SSXD data is proposed in this study. There are four critical angles related to the effects of spillover of the incident X-ray beam from the specimen face in the CSI-SSXD data. Exact values of cumulants of the equatorial aberration function are efficiently evaluated by 4 × 4 point two-dimensional Gauss–Legendre integral. A naïve two-step deconvolutional method has been applied to remove the effects of the first and third-order cumulants of the equatorial aberration function from the observed CSI-SSXD data. The performance of the algorithm has been tested by analyses of CSI-SSXD data of three LaB6 powder specimens with the widths of 20, 10, and 5 mm, collected with a diffractometer with the goniometer radius of 150 mm.

The crystal structure of a novel high-energy density material 3-[(3,4-dinitro-1H-pyrazol-1-yl)-NNO-azoxy]-4-nitro-1,2,5-oxadiazole C5HN9O8 was determined and refined using laboratory powder diffraction data. The diffraction data and database analysis were insufficient to distinguish two candidate structures from the solution step. Density functional theory with periodic boundary conditions optimizations were used to choose the correct one. 3-[(3,4-Dinitro1H-pyrazol-1-yl)-NNO-azoxy]-4-nitro-1,2,5-oxadiazole crystallizes in space group Pbca with a = 8.3104(2) Å, b = 14.2198(5) Å, c = 19.4264(7) Å, V = 2295.66(14) Å3. The molecular conformation contains a weak intramolecular hydrogen bond C–H⋯O–N, and the structure is dominated by weak O⋯π and O⋯O contacts.

The crystal structure of levocetirizine dihydrochloride Form I has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Levocetirizine dihydrochloride Form I apparently crystallizes in space group P21/n (#14) with a = 24.1318(21), b = 7.07606(9), c = 13.5205(7) Å, β = 97.9803(4)°, V = 2286.38(12) Å3, and Z = 4. The crystal structure consists of interleaved double columns of cations and anions along the short b-axis. The hydrogen bonds link the cations and anions along this axis. Each protonated nitrogen atom forms a strong N–H⋯Cl hydrogen bond to one of the chloride anions. The carboxylic acid group also forms an H-bond to Cl56, resulting in a ring with a graph set R1,2(10). The centrosymmetric P21/n model for the crystal structure of levocetirizine dihydrochloride is better than the non-centrosymmetric P21 model, even though levocetirizine is a chiral molecule; the sample exhibits weak second-harmonic generation, and three weak peaks which violate the glide plane are observed. The centrosymmetric model is better by statistical, graphical, and energetic measures, as well as by chemical reasonableness. To accommodate the chiral molecule in a centrosymmetric space group, the chiral central carbon atom was disordered over two half-occupied positions, so that each cation site could be occupied by a cation of the correct chirality. A powder pattern from a Le Bail extraction of this synchrotron data set is included in the Powder Diffraction File™ as entry 00-066-1627.

Synchrotron powder diffraction data is presented for the monoclinic polymorph of dimethylarsinic acid, (CH3)2AsO(OH) (DMAV). Rietveld refinement with GSASII yielded lattice parameters of a = 15.9264(15) Å, b = 6.53999(8) Å, c = 11.3401(9) Å, and β = 125.8546(17)° (Z = 8, space group C2/c). The Rietveld-refined structure was compared with both a density functional theory (DFT)-optimized structure and the published, low-temperature single-crystal structure, and all three structures exhibited excellent agreement. The triclinic polymorph of DMAV was also DFT optimized with CRYSTAL17 to determine the positions of the hydrogen atoms. Monoclinic DMAV forms zigzag chains parallel to the b-axis with adjacent DMAV molecules connected by an O–H⋯O bond, whereas triclinic DMAV forms dimers connected by two O–H⋯O bonds.

The crystal structure of palbociclib isethionate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Palbociclib isethionate crystallizes in space group P-1 (#2) with a = 8.71334(4), b = 9.32119(6), c = 17.73725(18) Å, α = 80.0260(5), β = 82.3579(3), γ = 76.1561(1)°, V = 1371.282(4) Å3, and Z = 2. The crystal structure is dominated by cation⋯anion and cation⋯cation hydrogen bonds, which result in layers roughly parallel to the (104) plane. Both hydrogen atoms on the protonated nitrogen atom of the pyrimidine ring participate in strong hydrogen bonds to the anions. One proton binds to the sulfonate group, while the other bonds to the hydroxyl group of the isethionate anion. The hydroxyl group of the anion acts as a donor to a ketone oxygen atom in the cation. There are also strong N–H⋯N hydrogen bonds, which occur in pairs linking the cations into dimers with rings having a graph set R2,2(8). The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™.

The crystal structure of varenicline hydrogen tartrate Form B (Chantix®) has been refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Varenicline hydrogen tartrate Form B crystallizes in space group P212121 (#19) with a = 7.07616(2), b = 7.78357(2), c = 29.86149(7) Å, V = 1644.706(6) Å3, and Z = 4. The hydrogen bonds were identified and quantified. Hydrogen bonds link the cations and anions in zig-zag chains along the b-axis. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

The crystal structure of pazopanib hydrochloride Form 1 has been refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Pazopanib hydrochloride crystallizes in space group P-1 (#2) with a = 8.45008(6), b = 8.71310(12), c = 16.05489(35) Å, α = 79.5996(9), β = 86.4784(5), γ = 87.3764(3)°, V = 1159.724(9) Å3, and Z = 2. The crystal structure is essentially identical to that of CSD Refcode CEVYEK. There are four strong N–H⋯Cl hydrogen bonds to the chloride anion. Several additional weaker N–H⋯Cl and C–H⋯Cl hydrogen bonds are also present. A variety of C–H⋯O, C–H⋯N, and N–H⋯S hydrogen bonds also contribute to the lattice energy. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™.

The crystal structure of daclatasvir dihydrochloride Form N-2 (Daklinza®) has been refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Daclatasvir dihydrochloride, Form N-2, crystallizes in space group P1 (#1) with a = 7.54808 (15), b = 9.5566 (5), c = 16.2641 (11) Å, α = 74.0642 (24), β = 84.0026 (13), γ = 70.6322 (5)°, V = 1064.150(11) Å3, and Z = 1. The hydrogen bonds were identified and quantified. Strong N–H⋯Cl hydrogen bonds link the cations and anions in chains along the a-axis. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).