Ce2SeN2: Ternary selenide nitride containing tetravalent Ce in the Ce2SO2 structure type

The new ternary dicerium selenide dinitride, Ce2SeN2, has been structurally characterized by single crystal X-ray diffraction. The title compound crystallizes in the trigonal space group P3¯m1 (#164, a = 4.0772(3) Å, c = 7.0477(7) Å, V = 101.46(2) Å3, Z = 1, and R/wR = 0.0212/0.0500) and adopts Ce2SO2 structure type. The Ce atoms form hexagonal closed packed layers perpendicular to the crystallographic c axis with AB stacking. The Se atoms occupy all the octahedral voids between every other pair of Ce layers, while the N atoms occupy all the tetrahedral voids between the remaining pairs of Ce layers. In this compound, Ce atom has 4+ oxidation state in contrast to the 3+ oxidation state observed in other compounds adopting the Ce2SO2 structure type.

The projected view of Ce2SeN2 down the [100] direction. Large letters denote the packing sequence of the Ce atoms (yellow circles) along the c axis. Se (black circles) and N (red circles) atoms occupy the octahedral and tetrahedral holes, respectively, between close packed Ce layers. Figure optionsDownload as PowerPoint slide