One hundred years ago X-ray powder diffraction, one of the premier techniques used in the characterization of materials, was invented. Its origins can be traced to two landmark contributions presented to the scientific community in 1916. They are the better known and celebrated work carried out by Paul Scherrer under the guidance of Peter W. Debye, at the University of Göttingen, Germany, and the lesser known work of Albert W. Hull performed at the Research Laboratory of the General Electric Company, Schenectady, NY, USA. The great contributions of Scherrer and Debye have been prominently recognized. They are presented in many textbooks and in technical and scientific articles published in the area of characterization of materials using powder diffraction techniques. The camera designed by them, later called “the Debye–Scherrer camera”, was used extensively for many years and the experimental setup (“the Debye–Scherrer geometry”) is still used today. On the other hand, the work performed by Hull has not been adequately appreciated and remembered. In this communication, an account of his contributions to X-ray powder diffraction and to crystallography is presented at 100 years of his landmark publication, which appeared in the first issue of Physical Review of 1917.

Representative compounds of the new family of magnetic materials Gd5−xNdxSi4 were analyzed by X-ray diffraction at the XRD1 beamline at Laboratório Nacional de Luz Síncrotron. To reduce X-ray absorption, thin layers of the powder samples were mounted outside the capillaries and measured in Debye–Scherrer geometry as usual. The XRD analyses and the magnetometry results indicate that the behavior of the magnetic transition temperature as a function of Nd content may be directly related to the average of the four smallest interatomic distances between different rare earth sites of the majority phase of each compound. The quality and consistency of the results show that the XRD1 beamline is able to perform satisfactory XRD experiments on high-absorption materials even off the best conditions.

An organic polar hydrate was obtained through cocrystallization of 2,4-diaminotoluene (2,4-DAT) and L(+)-tartaric acid (TA) from ethanol. Dehydration behavior of the obtained hydrate was investigated using variable temperature powder X-ray diffraction (PXRD) and thermal analysis. Proton transfer from L(+)-TA to 2,4-DAT in both hydrate and dehydrated form was revealed via Fourier transform infrared spectroscopy. The crystal structures of both forms were determined using PXRD techniques. The similarities and differences between two crystal structures were analyzed and the role of water in the hydrate crystal structure was demonstrated.

Three spinel materials were prepared and characterized by in situ powder X-ray diffraction (PXRD) techniques to track their phase changes that occurred in the typical batch synthesis process from a sol–gel mixture to the final crystalline spinel oxide. The materials were also characterized by thermal gravimetric analysis, whereby the materials decomposition mechanisms that were observed as the precursor, was gradually heated to the final oxide. The results showed that all the materials achieved their total weight loss at about 400 °C. The in situ PXRD analysis showed the progression of the phase transitions where certain of the materials changed from a crystalline precursor to an amorphous intermediate phase and finally to the spinel cathode oxide (Li1.03Mg0.2Mn1.77O4). For other materials, the precursor would start as an amorphous phase and upon heating, convert into an impure intermediate phase (Mn2O3) before forming the final spinel oxide (Li1.03Mn1.97O4). On the other hand, the LiAl0.4Mn1.6O4 would start with an amorphous precursor, with no intermediate phases and immediately formed the final spinel oxide phase. The in situ PXRD study also showed the increases in the materials respective lattice parameters of the crystalline unit cells upon heating and the significant increases in their crystallite sizes when heated above 600 °C.

The crystal structure of hydrocortisone acetate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Hydrocortisone acetate crystallizes in space group P21 (#4) with a = 8.85173(3) Å, b = 13.53859(3) Å, c = 8.86980(4) Å, β = 101.5438(3)°, V = 1041.455(6) Å3, and Z = 2. Both hydroxyl groups form hydrogen bonds to the ketone oxygen atom on the steroid ring system, resulting in a three-dimensional hydrogen bond network. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™.

Alpha lipoic acid (ALA) C8H14O2S2 is a naturally occurring compound that is synthesized in small amounts by plants and animals, including humans. ALA is covalently bound to specific proteins, which function as cofactors for several important mitochondrial enzyme complexes and studies suggest that they might help with type 2 diabetes. In the Cambridge Structural Database, there are four entries related to this compound: two for lipoic acid and two for complexes. In the Powder Diffraction File-4, two experimental unindexed patterns are reported. The material crystallizes in a monoclinic crystal system, space group P21/a and cell parameters a = 9.237 (1) Å, b = 9.960 (1) Å, c = 11.787 (2) Å, β = 109.13 (1)°, and V = 1024.6 (2) Å3.

The new ternary compound of Al2Cu3Gd was prepared by melting with stoichiometric composition in an electric arc furnace. The X-ray powder diffraction data of Al2Cu3Gd have been collected by the Rigaku Smart Lab X-ray powder diffractometer. The Rietveld refinement method had been used to study the crystal structure of Al2Cu3Gd. The results showed that the Al2Cu3Gd, new compound have the hexagonal structure, space group P6/mmm (No. 191) with a = 5.1822 (1) Å, c = 4.1566 (1) Å, V = 96.67 Å3, Z = 1, and the density is 6.62 g cm−3, and the intensity ratio reference intensity ratio is 1.29.

Synchrotron powder diffraction data have been obtained and indexed for ferrous gluconate, a common supplement used for the treatment and prevention of iron-deficiency anemia. Ferrous gluconate (Fe(C6H11O7)2 · x H2O, Z = 4) crystallizes in a monoclinic cell (space group I2, #5) with lattice parameters a = 19.953 16(9) Å, b = 5.513 92(3) Å, c = 18.470 58(9) Å, and β = 111.3826(3)°. The pattern shows no evidence of impurity reflections.

X-ray powder diffraction data, unit-cell parameters, and space group for Ethyl (Z)-2-chloro-2-[2-(4-methoxyphenyl)hydrazin-1-ylidene]acetate, C11H13ClN2O3, are reported [a = 13.308(4) Å, b = 9.908(5) Å, c = 4.753(4) Å, α = 90°, β = 91.510(8)°, γ = 90°, unit-cell volume V = 626.64 Å3, Z = 2, ρcal = 1.361 g cm−3, and space group P21]. All measured lines were indexed and are consistent with the P21 space group. No detectable impurities were observed.

X-ray powder diffraction data, unit-cell parameters, and space group for alogliptin benzoate, C18H21N5O2·C7H6O2, are reported [a = 28.8260(8) Å, b = 9.9654(4) Å, c = 8.1477(8) Å, α = 90, β = 90, γ = 90°, unit-cell volume V = 2340.57 Å3, Z = 4, ρcal = 1.3097 g cm−3, and space group P212121]. All measured lines were indexed and are consistent with the P212121 space group, No detectable impurities were observed.