Synchrotron X-ray Powder Diffraction Data Research Articles

Synthesis and Structure of Oxygen Deficient Lead-Technetium Pyrochlore, the First Example of a Valence V Technetium Oxide.

The structure of lead-technetium pyrochlore has been refined in space group with a = 10.36584(2) Å using a combination of synchrotron X-ray and neutron powder diffraction data and confirmed via Electron Diffraction. The oxide is found to be oxygen deficient with a stoichiometry of Pb2Tc2O7-d. Displacive disorder of the Pb cations is evident from the refinements, as has been observed in Bi2Tc2O7-d. X-ray absorption spectroscopic measurements at the Tc K-edge demonstrate the valence of the Tc is greater than 4.0 as anticipated from the refined oxygen stoichiometry. Raman spectroscopy confirms the presence of disorder leading us to conclude that this pyrochlore is the first example of a valence V technetium oxide.

Powder X-ray diffraction of varenicline hydrogen tartrate Form B (Chantix®), (C13H14N3)(HC4H4O6)

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®).

Magnetic ground state and crystal structure of the giant dielectric constant material Ba(Fe1/2Nb1/2)O3

The room temperature crystal structure as well as the magnetic ground state of Ba(Fe1/2Nb1/2)O3 (BFN) are controversial. The results of Rietveld refinements using high-resolution synchrotron x-ray powder diffraction (SXRPD) data are presented to show that BFN belongs to cubic perovskite structure in the Pm3¯m space group and not in the cubic Fm3¯m or monoclinic symmetries, proposed by some earlier workers based on the analysis of the laboratory source XRD data. The temperature dependent specific heat measurements in the 1.8 to 300 K range on well characterized BFN samples are presented to show the absence of any long-range ordered (LRO) antiferromagnetic (AFM) transition, proposed by some earlier workers based on the observation of a peak in the temperature dependence of zero-field cooled (ZFC) DC magnetization around 25 to 32 K. Results of temperature dependent magnetization measurements during warming cycle on ZFC and field cooled (FC) BFN samples reveal history dependent bifurcation with a peak in the ZFC M (T) curve at Tf ~ 29 K, in agreement with some previous results where it was attributed to a spin-glass transition even though such an irreversibility can result from superparamagnetic (SPM) blocking as well. The appearance of a short plateau in our FC M (T) curve below Tf suggests a cluster spin-glass phase of BFN below Tf. This was confirmed by us through the ac susceptibility χ' (T, ω) studies which reveal divergence of spin dynamics at the spin-glass transition temperature TSG ~ (28 ± 1) K with a large characteristic spin relaxation time τ0 ~ 10−6 s following Vogel-Fulcher as well as power-law type critical dynamics. The existence of the magnetic glassy state in BFN is further supported by the observation of (1) magnetic field dependent shift of Tf with increasing magnetic field along the de Almeida-Thouless line in the T-H plane with a characteristic exponent of m = 2/3, (2) weak remanent magnetization Mr below Tf with exponentially decreasing Mr on approaching Tf, (3) extremely slow decay of the thermoremanent magnetization below Tf with time as per a stretched exponential function, and (4) characteristic aging, rejuvenation and memory effects below Tf. These results provide the first unambiguous confirmation of the cluster spin-glass state of BFN and settle the existing controversies related to its magnetic ground state.

Crystal structure of palbociclib isethionate Form B, (C24H30N7O2)(C2H5O4S)

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™.

KTb(MoO4)2 Green Phosphor with K+-Ion Conductivity: Derived from Different Synthesis Routes.

The influence of different synthesis routes on the structure and luminescent properties of KTb(MoO4)2 (KTMO) was studied. KTMO samples were prepared by solid-state, hydrothermal, and Czochralski techniques. These methods lead to the following different crystal structures: a triclinic scheelite-type α-phase is the result for the solid-state method, and an orthorhombic KY(MoO4)2-type γ-phase is the result for the hydrothermal and Czochralski techniques. The triclinic α-KTMO phase transforms into the orthorhombic γ-phase when heated at 1273 K above the melting point, while KTMO prepared by the hydrothermal method does not show phase transitions. The influence of treatment conditions on the average crystallite size of orthorhombic KTMO was revealed by X-ray diffraction line broadening measurements. The electrical conductivity was measured on KTMO single crystals. The orthorhombic structure of KTMO that was prepared by the hydrothermal method was refined using synchrotron powder X-ray diffraction data. K+ cations are located in extensive two-dimensional channels along the c-axis and the a-axis. The possibility of K+ migration inside these channels was confirmed by electrical conductivity measurements, where strong anisotropy was observed in different crystallographic directions. The evolution of luminescent properties as a result of synthesis routes and heating and cooling conditions was studied and compared with data for the average crystallite size calculation and the grain size determination. All samples' emission spectra exhibit a strong green emission at 545 nm due to the 5D4 → 7F5 Tb3+ transition. The maximum of the integral intensity emission for the 5D4 → 7F5 emission under λex = 380 nm excitation was found for the KTMO crashed single crystal.

Manjiroite or hydrous hollandite?

Abstract In this study, we investigated an unusual natural Mn oxide hollandite-group mineral from the Kohare Mine, Iwate Prefecture, Japan, that has predominantly water molecules in the tunnels, with K, Na, Ca, and Ba. The specimens are labeled as type manjiroite, but our analyses show that Na is not the dominant tunnel species, nor is it even the primary tunnel cation, suggesting either an error in the original analyses or significant compositional variation within samples from the type locality. Chemical analyses, X-ray photoelectron spectroscopy, and thermal gravimetric analysis measurements combined with Rietveld refinement results using synchrotron X-ray powder diffraction data suggest the chemical formula: (K0.19Na0.17Ca0.03Ba0.01H2O1.60)(Mn5.024+Mn2.823+Al0.14Fe0.02)O13.47(OH)2.53. Our analyses indicate that water is the primary tunnel species, and although water has been reported as a component in natural hollandites, this is the first detailed study of the crystal structure and dehydration behavior of a natural hydrous hollandite with water as the predominant tunnel species. This work underscores the rarity of natural Na-rich hollandite phases and focuses new attention on the role of hydrous components of hollandite-like phases in determining their capacities to exchange or accommodate various cations, such as Li+, Na+, Ba2+, Pb2+, and K+ in natural systems.

Crystal structure and morphology of the bright orange γ-phase of Pigment Red 53:2 from XRPD, DFT+D and TEM

Pigment Red 53:2 (P R.53:2), the calcium lake of P.R.53, in its γ-phase is a bright orange pigment suitable for printing applications and for the colouration of seeds. The γ-phase forms needle-like, long thin crystals, which are often bent, as seen by transmission electron microscopy (TEM). Its crystal structure was determined from synchrotron X-ray powder diffraction data supported by lattice-energy minimisations with dispersion-corrected density functional theory (DFT+D). The γ-phase is a dihydrate with the chemical composition Ca(C17H12ClN2O4S)2 · 2H2O. The calcium ion is coordinated by seven oxygen atoms, which come from the sulfonate groups of four anions, one carbonyl group and two water molecules. The structure contains columns which are built by the Ca2+ ions, the water molecules, and the pigment anions, with their sulfonate and carbonyl groups directed inward, and their non-polar phenyl and naphthalene groups pointing outwards. All columns are parallel. Neighbouring columns are connected by van der Waals forces only. This explains the observed bent hair-like morphology of the crystals.

Powder X-ray diffraction of pazopanib hydrochloride Form 1, C21H24N7O2SCl

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™.

Crystal Structure of BaCa(CO3)2 Alstonite Carbonate and Its Phase Stability upon Compression.

New single-crystal X-ray diffraction experiments and density functional theory (DFT) calculations reveal that the crystal chemistry of the CaO–BaO–CO2 system is more complex than previously thought. We characterized the BaCa(CO3)2 alstonite structure at ambient conditions, which differs from the recently reported crystal structure of this mineral in the stacking of the carbonate groups. This structural change entails the existence of different cation coordination environments. The structural behavior of alstonite at high pressures was studied using synchrotron powder X-ray diffraction data and ab initio calculations up to 19 and 50 GPa, respectively. According to the experiments, above 9 GPa, the alstonite structure distorts into a monoclinic C2 phase derived from the initial trigonal structure. This is consistent with the appearance of imaginary frequencies and geometry relaxation in DFT calculations. Moreover, calculations predict a second phase transition at 24 GPa, which would cause the increase in the coordination number of Ba atoms from 10 to 11 and 12. We determined the equation of state of alstonite (V0 = 1608(2) Å3, B0 = 60(3) GPa, B′0 = 4.4(8) from experimental data) and analyzed the evolution of the polyhedral units under compression. The crystal chemistry of alstonite was compared to that of other carbonates and the relative stability of all known BaCa(CO3)2 polymorphs was investigated.

Crystal structure of levocetirizine dihydrochloride Form I, C21H27ClN2O3Cl2

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.

Rietveld refinement of the low temperature crystal structures of Cs2XSi5O12 (X = Cu, Cd and Zn)

The synthetic leucite silicate framework mineral analogues Cs2XSi5O12 (X = Cu, Cd, Zn) were prepared by high-temperature solid-state synthesis. The results of Rietveld refinement, using 18 keV synchrotron X-ray powder diffraction data collected at low temperatures (8K X = Cu, Zn; 10K X = Cd) show that the title compounds crystallize in the space group Pbca and are isostructural with the ambient temperature structures of these analogues. The structures consist of tetrahedrally coordinated SiO4 and XO4 sharing corners to form a partially substituted silicate framework. Extraframework Cs cations sit in channels in the framework. All atoms occupy the 8c general position for this space group. In these refined structures, silicon and X atoms are ordered onto separate tetrahedrally coordinated sites (T-sites).

Crystal Structure of Linagliptin Hemihydrate Hemiethanolate (C25H28N8O2)2(H2O)(C2H5OH) from 3D Electron Diffraction Data, Rietveld Refinement, and Density Functional Theory Optimization

The crystal structure of linagliptin hemihydrate hemiethanolate was solved by direct methods and refined by least-squares on the basis of 3D electron diffraction data. Linagliptin is one of the largest organic structures solved ab initio by electron diffraction. The good quality of the data allows the recognition of subtle symmetry reductions and of fine differences in the configuration of the two independent molecules that make up the structure. The structure was then further refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. The linagliptin hemihydrate hemiethanolate structure is very similar to the known linagliptin water/methanol/ethanol Form I, and crystallizes in space group P21212 (#18) with a = 24.85091(13), b = 21.56916(9), c = 9.74376(4) Å, V = 5222.79(3) Å3, and Z = 4. Although the compounds are similar, they are not the same, so the linagliptin hemihydrate hemiethanolate structure is a novel one. The powder pattern from a Le Bail fit to synchrotron data is included in the Powder Diffraction File as entry 00-066-1626.

Amorphous dispersions of flubendazole in hydroxypropyl methylcellulose: Formulation stability assisted by pair distribution function analysis

We use X-ray pair distribution function (PDF) analysis applied to high-energy synchrotron X-ray powder diffraction data to evaluate the amorphous solid dispersions interactions and their aging stability. The obtained systems are based on hydroxypropyl methylcellulose (hypromellose) derivatives and flubendazole (FBZ) drug dispersions prepared using a spray-dryer technique. We carry out stability studies under aging parameters (40 °C/75% relative humidity) to tune the systems’ recrystallization. The results reveal that ion-base interactions between the drug-polymer matrix are responsible for reducing clustering processes yielding slower recrystallization and different ordering in the hypromellose phthalate (HPMCP/FBZ) and hypromellose acetate succinate (HPMC-AS/FBZ) systems and complete drug clustering in hypromellose (HPMC-E3/FBZ). The structural ordering was accessed using differential X-ray PDFs that revealed the region between 3.5 Å and 5.0 Å could be related to FBZ intermolecular interactions and is more ordered for the least stable system (HPMC-E3/FBZ) and less ordered for the most stable system (HPMCP/FBZ). These results show that the ion-base interactions between drug and matrix occur at these intermolecular distances.

Crystal structure of eltrombopag olamine Form I, (C2H8NO)2 (C25H20N4O4)

The crystal structure of eltrombopag olamine Form I has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Eltrombopag olamine crystallizes in the space group P21/n (#14) with a = 17.65884(13), b = 7.55980(2), c = 22.02908(16) Å, β = 105.8749(4)°, V = 2828.665(11) Å3, and Z = 4. The crystal structure is dominated by columns of hydrogen-bonded cations and anions along the short b-axis. van der Waals interactions bind the columns together. Two H atoms of each ammonium group in the ethanolammonium cations participate in strong hydrogen bonds, and the third H forms weaker bifurcated H-bonds. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

Unveiling unique structural features of the YNU-5 aluminosilicate family

YNU-5 (YFI type) is the first zeolite reported with interconnected 12-, 12-, and 8-ring pores showing a remarkable catalytic potential towards the dimethyl ether (DME)-to-olefin reaction. In this work, the structures of the as-synthesized, calcined and dealuminated YNU-5 zeolites, were investigated by various techniques with special emphasis on advanced electron microscopy methods. The frameworks of the three materials were solely determined by three-dimension electron diffraction tomography, and the space group for the three of them was determined to be Cmmm, which is of higher symmetry than the previous reported result. Rietveld refinement was performed against synchrotron Powder X-ray diffraction data in order to obtain precise information of the framework and to locate the organic species, cations and water. Additionally, spherical aberration-corrected scanning transmission electron microscopy was employed to study the local fine structure and to indicate surface reconstruction associated to the displacement of the vacancies through the dealumination process. Finally, a minor phase, whose structure was solved by electron microscopy was found to be MSE framework type, appeared in all the three YNU-5 materials. Overall, the electron microscopy analyses reported in the present work provide additional information regarding the YNU-5 structure in terms of space group determination, additional surface terminations and the identification of a minor phase.

Crystal structure of tofacitinib dihydrogen citrate (Xeljanz®), (C16H21N6O)(H2C6H5O7)

The crystal structure of tofacitinib dihydrogen citrate (tofacitinib citrate) has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Tofacitinib dihydrogen citrate crystallizes in space group P212121 (#19) with a = 5.91113(1), b = 12.93131(3), c = 30.43499(7) Å, V = 2326.411(6) Å3, and Z = 4. The crystal structure consists of corrugated layers perpendicular to the c-axis. Within the layers, cation⋯anion and anion⋯anion hydrogen bonds link the fragments into a two-dimensional network parallel to the ab-plane. Between the layers, there are only van der Waals contacts. A terminal carboxylic acid group in the citrate anion forms a strong charge-assisted hydrogen bond to the ionized central carboxylate group. The other carboxylic acid acts as a donor to the carbonyl group of the cation. The citrate hydroxy group forms an intramolecular charge-assisted hydrogen bond to the ionized central carboxylate. Two protonated nitrogen atoms in the cation act as donors to the ionized central carboxylate of the anion. These hydrogen bonds form a ring with the graph set symbol R2,2(8). The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

Crystal structure of tamsulosin hydrochloride, C20H29N2O5SCl

The crystal structure of tamsulosin hydrochloride has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Tamsulosin hydrochloride crystallizes in space groupP21(#4) witha= 7.62988(2),b= 9.27652(2),c= 31.84996(12) Å,β= 93.2221(2)°,V= 2250.734(7) Å3, andZ= 4. In the crystal structure, two arene rings are connected by a carbon chain oriented roughly parallel to thec-axis. The crystal structure is characterized by two slabs of tamsulosin hydrochloride molecules perpendicular to thec-axis. As expected, each of the hydrogens on the protonated nitrogen atoms makes a strong hydrogen bond to one of the chloride anions. The result is to link the cations and anions into columns along theb-axis. One hydrogen atom of each sulfonamide group also makes a hydrogen bond to a chloride anion. The other hydrogen atom of each sulfonamide group forms bifurcated hydrogen bonds to two ether oxygen atoms. The powder pattern is included in the Powder Diffraction File™ as entry 00-065-1415.

Crystal structure of edoxaban tosylate monohydrate Form I, (C24H31ClN7O4S)(C7H7O3S)(H2O)

The crystal structure of edoxaban tosylate monohydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Edoxaban tosylate monohydrate crystallizes in space group P21 (#4) with a = 7.55097(2), b = 7.09010(2), c = 32.80420(21) Å, β = 96.6720(3)°, V = 1744.348(6) Å3, and Z = 2. The crystal structure consists of alternating layers of edoxaban cations and tosylate anions along the c-axis. The water molecules lie near the sulfonate end of the tosylate anions. The solid-state conformation of the edoxaban cation is determined by intermolecular interactions. The protonated nitrogen atom forms a strong N–H⋯O hydrogen bond to one of the tosylate oxygens. Only one of the water molecule hydrogens acts as a donor in an O–H⋯O hydrogen bond. The tosylate oxygens act as acceptors in a number of C–H⋯O hydrogen bonds. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™.

Crystal structure of pomalidomide Form I, C13H11N3O4

The crystal structure of pomalidomide Form I has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Pomalidomide Form I crystallizes in the space group P-1 (#2) with a = 7.04742(9), b = 7.89103(27), c = 11.3106(6) Å, α = 73.2499(13), β = 80.9198(9), γ = 88.5969(6)°, V = 594.618(8) Å3, and Z = 2. The crystal structure is characterized by the parallel stacking of planes parallel to the bc-plane. Hydrogen bonds link the molecules into double layers also parallel to the bc-plane. Each of the amine hydrogen atoms acts as a donor to a carbonyl group in an N–H⋯O hydrogen bond, but only two of the four carbonyl groups act as acceptors in such hydrogen bonds. Other carbonyl groups participate in C–H⋯O hydrogen bonds. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

Crystal structure of tezacaftor Form A, C26H27F3N2O6

The crystal structure of tezacaftor Form A has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Tezacaftor Form A crystallizes in space group C2 (#5) with a = 21.05142(6), b = 6.60851(2), c = 17.76032(5) Å, β = 95.8255(2)°, V = 2458.027(7) Å3, and Z = 4. The crystal structure is dominated by van der Waals interactions. O–H⋯O hydrogen bonds link the molecules in chains along the b-axis, and there are a variety of C–H⋯O hydrogen bonds, both intra- and intermolecular. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).