The Structure of Hyperalkaline Aqueous Solutions Containing High Concentrations of Gallium - a Solution X-ray Diffraction and Computational Study

Highly concentrated alkaline NaOH/Ga(OH)3 solutions with 1.18 M Ga(III)T 2.32 M and 2.4 M NaOHT 4.9 M (where the subscript T denotes total or analytical concentrations) have been prepared and investigated by solution X-ray diffraction and also by ab initio quantum chemical calculations. The data obtained are consistent with the presence of only one predominant Ga(III)-bearing species in these solutions, that is the tetrahedral hydroxo complex Ga(OH)4–. This finding is in stark contrast to that found for Al(III)-containing solutions of similar concentrations, in which, besides the monomeric complex, an oxo-bridged dimer was also found to form. From the solution X-ray diffraction measurements, the formation of the dimeric (OH)3Ga–O–Ga(OH)32– could not unambiguously be shown, however, from the comparison of experimental IR, Raman and 71Ga NMR spectra with calculated ones, its formation can be safely excluded. Moreover, higher mononuclear stepwise hydroxo complexes, like Ga(OH)63–, that have been claimed to exist by others in the literature, was not possible to experimentally detect in these solutions with any of the spectroscopic techniques used

A mese terápiás célú felhasználása a szomatopedagógiában - Mozgásnevelés másképp

Dolgozatommal szeretnék egy olyan mozgásfoglalkozás során alkalmazott technikát bemutatni, melyet tudomásom szerint (szakirodalmak ismeretében és szakmabeliektől való értesülés alapján) eddig még nem alkalmaztak

Mesoporous carbon-supported Pd nanoparticles with high specific surface area for cyclohexene hydrogenation: Outstanding catalytic activity of NaOH-treated catalysts

Abstract Extremely high specific surface area mesoporous carbon-supported Pd nanoparticle catalysts were prepared with both impregnation and polyol-based sol methods. The silica template used for the synthesis of mesoporous carbon was removed by both NaOH and HF etching. Pd/mesoporous carbon catalysts synthesized with the impregnation method has as high specific surface area as 2250 m2/g. In case of NaOH-etched impregnated samples, the turnover frequency of cyclohexene hydrogenation to cyclohexane at 313 K was obtained ~ 14 molecules ∙ site− 1 ∙ s− 1. The specific surface area of HF-etched samples was higher compared to NaOH-etched samples. However, catalytic activity was ~ 3–6 times higher on NaOH-etched samples compared to HF-etched samples, which can be attributed to the presence of sodium and surface hydroxylgroups of the catalysts etched with NaOH solution