Binary inorganic compounds of rare earths with an intermediate valence

The valent state of rare earth ions in binary inorganic compounds with the elements of groups 1-7 (excluding compounds with the elements of group 2 which are typical intermatallides and require a special review due to ample material) on the basis of crystallochemical properties and analysis of the dependence of elementary cell dimensions on ionic radius of trivalent rare earths, is estimated. The study of magnetic properties has permitted to estimate ytterbium effective valence ( state with intermediate valence) in dehydride as Yb2,55+H2. Rare earth ions in inorganic compounds reveal quite definite deviation from the characteristic oxidation degree 3+ ( either 2+ or 4+). A regular deviation of oxidation degree ( state with intermediate valence) of rare earth ions in accordance with periodic change of structure of rare earth atom electron shells is estabished