Present state of research on the sorption of inorganic compounds by oxide hydroxides from aqueous solutions

Abstract

In this experiment we investigated the synthesis of the double mercury layer compound Hg 2 Ba 2 YCu 2 O 8−δ (Hg-2212) at 4 GPa and 900 • C by in situ x-ray diffraction performed at the high-pressure ID30 beam line at ESRF. The chemical path observed depends on the choice of the initial mixture. If one starts from a mixture of oxides and copper, an intermediate oxide phase (a high-pressure variety) containing barium and mercury is formed (we do not know if copper is present). This intermediate phase is then converted into the final Hg-2212 product. On the other hand, Hg-2212 grows directly from a pre-reacted precursor 'Ba 2 YCu 2 O y ' mixed with HgO. This in situ technique clearly shows its efficiency in identifying, in real time, a phase that would have been difficult to observe ex situ.