Isotope effect in the hydrogen distribution in the solid solution TiN0.40H0.19D0.19
Аннотация
The structure of a solid solution with a combined isotope composition based on TiN0.40H0.19D0.19 (space group $$ P\overline 3 m1 $$ ) has been studied by neutron diffraction. The isotope effect in the distribution of H and D isotopes has been found: the isotopes are located in tetrahedral interstices of the same type but with different z coordinates; there is splitting of 2d tetrahedral interstices into two groups, the protium (H) and deuterium (D). Therefore, in the ordered “layered” structure of the TiN0.40H0.19D0.19 solid solution, two different isotopes of the same element cannot be located at the same plane perpendicular to the threefold axis. The crystal-chemical analysis of the surroundings of H and D has been performed, and considerable differences have been revealed between the coordination polyhedra surrounding different hydrogen isotopes. It has been found that, in some metal-hydrogen systems, protium and deuterium should be treated as independent chemical components.