In this work, the reduction mechanism of potassium chromate (K2CrO4) was investigated via in situ high-temperature X-ray diffraction coupled with Fourier transform infrared spectroscopy. During the hydrogen reduction of K2CrO4, the formation of K3CrO4, KCrO2, and KxCrO2 were detected for the first time. The study discovered that K2CrO4 was firstly reduced to K3CrO4 and an amorphous Cr(III) intermediate product at low temperature (400–500 °C). Moreover, the K3CrO4 was the only crystalline material at this stage. As the temperature increased, a stabilized amorphous CrOOH was formed. At a high temperature (550–700 °C), KCrO2 was generated. Interestingly, a portion of KCrO2 was spontaneously decomposed during the hydrogen reduction, accompanying by the formation of K0.7CrO2. Finally, the results clearly illustrated the reduction mechanism of K2CrO4: K2CrO4 → K3CrO4 → amorphous intermediate → KCrO2.

Novel compounds Ca8−xPbxZnBi(VO4)7 (0 ≤ x ≤ 1.5) solid solution with the whitlockite-type structure were synthesized by a standard solid-state method. The unit-cell parameters were determined by X-ray powder diffraction and using Le Bail decomposition. The crystal structural of Ca6.5Pb1.5ZnBi(VO4)7 was refined by Rietveld method. It is found that Pb2+ cations occupy a half of the M3 site, whereas the M1 and M2 sites are predominantly occupied by calcium with admixture of Bi3+ cations. The M5 site is fully occupied by Zn2+ cations. The M4 site in the structure of studied sample remains vacant and does not participate in the cations arrangement. Optical second harmonic generation demonstrates high non-linear optical activity. Dielectric investigations confirm polar space group R3c. Changes in the non-linear optical and ferroelectric parameters are matched with lead and zinc cation distribution over the sites of the whitlockite-type structure.

The crystal structure of the purpureo salt, [Co(NH3)5Cl]Cl2, first reported in 1963 and later revised in 1968 (in both cases from single-crystal diffraction) in the space group Pnma (No. 62), has been recently re-examined from synchrotron X-ray powder diffraction using direct methods and the software EXPO2013. The comparison of the Rietveld analysis results using the two published models and the atomic coordinates obtained from powders leads to an improved crystal structure description in the lower symmetry space group Pn21a (No. 33). As a result, the overall atom connectivity and crystal packing remain similar; however, the symmetry and internal geometry of the coordination complex are changed. The distortions from an idealized geometry in Pnma (No. 62) are likely because of energetically favorable hydrogen-bonding motifs in the crystal. The three models are compared, and their validity and limitations are discussed.

Lithol reds belong to the group of azo pigments, which were popular artists’ colouring materials in the first half of the twentieth century. These pigments were also used in many branches of industry. Here, we report X-ray powder diffraction data, unit-cell parameters, and space groups for three compounds from this group: sodium (E)-2-((2-hydroxynaphthalen-1-yl)diazenyl)naphthalene-1-sulphonate monohydrate (Na lithol red), monoclinic, space group C2/c, with cell parameters a = 33.343(7), b = 6.667(2), c = 16.397(4) Å, β = 90.83°, V = 3644.51 Å3, Z = 8; barium (E)-2-[(2-hydroxynaphthalen-1-yl)diazenyl]naphthalene-1-sulphonate trihydrate (Ba lithol red), monoclinic, space group P21/m, with cell parameters a = 17.758(9), b = 6.209(4), c = 16.857(8) Å, β = 92.07°, V = 1857.39 Å3, Z = 2; and ammonium (E)-2-[(2-hydroxynaphthalen-1-yl)diazenyl]naphthalene-1-sulphonate monohydrate (NH4 lithol red), monoclinic, space group P2/c, with cell parameters a = 17.721(5), b = 6.428(3), c = 16.911(5) Å, β = 100.31(3)°, V = 1895.31 Å3, and Z = 4. In the first and third cases we synthesised the pigments in their monohydrate form, performed X-ray powder diffraction measurements, and indexed all of the obtained diffraction maxima. In the case of the barium compound, despite many efforts in the course of the synthesis procedure, the powder diffraction patterns of the obtained samples were not of the best quality. Nevertheless, we indexed the best one and found a reliable space group and cell parameters.

X-ray powder diffraction data, unit-cell parameters, and space group for S-2-(methylamino)-2-phenylcyclohexan-1-one hydrochloride, C13H18ClNO, are reported [a = 6.578 (1) Å, b = 13.250 (2) Å, c = 15.096 (2) Å, β = 91.619 (3)°, unit-cell volume V = 1315(1) Å3, Z = 4, 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 a C9H9I3N2O4 are presented [a = 17.000 (1) Å, b = 13.896 (1) Å, c = 12.597 (1) Å, unit-cell volume V = 2975.9 Å3, MW = 589.89, Tm (melting point) = 300(1) °C, ρc = 2.641 g cm−3, ρm = 2.66(3) g cm−3, Z = 8, space group Pbca]. All measured lines were indexed and are consistent with the Pbca space group. No detectable impurities were observed.

Ambroperuvin is a new pseudoguaianolide isolated from Ambrosia peruviana Willd., a plant used in traditional medicine in Venezuela. The analysis of the X-ray powder pattern being reported led to an orthorhombic unit cell with space group P212121 and cell parameters a = 15.999(6) Å, b = 11.263(2) Å, c = 9.112(2) Å. No detectable impurities were observed.

X-ray powder diffraction data, unit-cell parameters, and space group for ertapenem side chain, C20H19N3O7S, are reported [a = 4.907(6) Å, b = 18.686(3) Å, c = 22.071(1) Å, α = γ = 90°, β = 90.759(5)°, unit-cell volume V = 2023.82 Å3, Z = 4, ρcal = 1.462 g cm−3, and space group P21/c]. All measured lines were indexed and are consistent with the P21/c space group. No detectable impurity was observed.

1-(4-methoxyphenyl)-7-oxo-6-[4-(2-oxopiperidin-1-yl)phenyl]-4,5,6,7- tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester is an important intermediate in the synthesis of the anticoagulant, apixaban. X-ray powder diffraction data for this compound are reported [a = 14.101(4) Å, b = 10.105(6) Å, c = 9.532(7) Å, α = 72.774(1)°, β = 97.356(3)°, γ = 108.237(3)°, unit-cell volume V = 1231.45 Å3, Z = 2, and space group P-1]. No detectable impurities were observed.

The authors present here the superior result of synchrotron X-ray diffraction indexing of the 8 × 8 × 8 fluorite supercell, murataite, M8 (formula Ca66.37Mn29.33Ti186.76Zr83.35Al46.30Fe74.09O817, a = 39.277(3) Å, Z = 4). The authors present evidence that Fd$\bar 3$m (227) is the most likely space group.