No abstract

The monoclinic inherently oxygen‐ deficient compound La26O27□(BO3)8 can react with water vapor and incorporate protons by filling the oxygen‐ion vacancy and forming hydroxide ions, leading to the oxy‐hydroxy‐borate La26O26(OH)2(BO3)8. This reaction is reversible. The conductivity measured under wet conditions at 300 °C is that of La26O26(OH)2(BO3)8; at 600 °C the proton contribution to the total conductivity is still clearly visible (see figure).

International audienceThe framework of the high-temperature modification of NdBO3 is built up from NdO8 dodecahedra sharing edges and BO3 groups. The NdO8 polyhedra form corrugated sheets approximately parallel to the (111) plane and the borate groups are arranged in rows running parallel to the [011] direction. The Nd—O distances range from 2.315 (3) to 2.697 (4) A ° and the B—O distances from 1.346 (6) to 1.407 (6) A ° . The title structure is isotypic with triclinic EuBO3