Application of 12CaO•7Al2O3 electride as a new electrode for superoxide ion generation and hydroxylation of an arylboronic acid

Chloride‐Ion‐Stabilized Strontium Mayenite: Expansion of Versatile Material Family

“…4(b)] below x = 1 also agree with the starting compositions. For the composition with x = 2, which has excess Cl, the sintered sample consisted of Sr 3 12 the Ca or Sr sites are split into two to model the displacement of these cations toward the anions located at the cage centers. The refinement was therefore initially carried out by splitting the Sr sites into two.…”

“…For those with open-pore microstructures, the density was estimated from the weight and dimensions of the sample. The relative density of a sample was calculated as the ratio of the measured density to the theoretical density of the Sr-mayenite phase, which was evaluated to be 3.54 g/cm 3 by Rietveld refinement. Possible chemical reactions during sintering and the thermal stability after sintering were determined using a combination of thermogravimetric/differential thermal and evolved-gas analyses (TG-EGA; Thermoplus, Rigaku).…”

“…Electron paramagnetic resonance (EPR) spectroscopy was performed on this sample at 25°C, using a Bruker EMX spectrometer (Karlsruhe, Germany). The magnetic field of the spectrometer was calibrated using 2,2-diphenyl-1-picrylhydrazyl solution in benzene, which gives a g-value of 2.00345 (3). 25 The spin density in the sample was calibrated using standard samples of CuSO 4 Á5H 2 O.…”

“…15 However, the Sr-mayenite synthesized so far contains OH À ions in the cages, and is only a quasi-stable phase in the SrO-Al 2 O 3 pseudo-binary system. 16 12 Rigorous synthetic conditions are required, especially for the solid-state reaction route, where Sr-mayenite is never formed as the major phase when SrCO 3 or SrO is used as the Sr source, irrespective of the Al source and other reaction conditions. The establishment of easier synthetic routes with better thermal stabilities is an important step in material modifications by anion manipulation in Sr-mayenite-based materials.…”

“…Introduction 12CaOÁ7Al 2 O 3 (C 12 A 7 , mayenite) and its derivatives have been receiving attention because their crystal structures include nanosized cages, and manipulation of anions incorporated in the cages can result in some unusual properties. [1][2][3][4][5][6] Its structural formula is [Ca 24 Al 28 O 64 ] 4+ Á2O 2À , where the brackets indicate the unit cell of the lattice framework, containing 12 cages, and 2O 2À represents two extra-framework oxide ions partially (2/ 12) and randomly occupying cages. The substitution of cation sites is also important, especially for enhancing the positive charge of the lattice framework and relevant enhancement of anion occupancy of cages.…”