Two Non‐Isostructural Gadolinium Oxide Nitride Chalcogenides: Gd3ONSe2 and Gd3ONTe2

Abstract

AbstractTwo new non‐isostructural gadolinium(III) oxide nitride chalcogenides with the composition Gd3ONCh2 bearing selenide (Gd3ONSe2) and telluride (Gd3ONTe2) could be synthesized by the reaction of gadolinium metal (Gd) with gadolinium sesquioxide (Gd2O3), sodium azide (NaN3), selenium (Se) or tellurium (Te), iodine (I2) and sodium iodide (NaI) as flux in evacuated silica tubes for seven days at 850 to 950 °C. Yellow lath‐shaped single crystals of Gd3ONSe2 crystallize isotypically to Tb3ONSe2 in the monoclinic space group C2/m with the lattice parameters a = 1560.12(9), b = 395.24(2), c = 977.35(6) pm, β = 97.321(3)° (Z = 4). In contrast, orthorhombic Gd3ONTe2 forms black rods, appears in the space group Pnma with the lattice parameters a = 1337.87(8), b = 408.47(2), c = 1216.78(7) pm (Z = 4) and adopts the crystal structure of Nd3N2SeBr. Three crystallographically independent Gd3+ cations can be found in both oxide nitride chalcogenides, but their coordination spheres are different. The Gd3+ cations in Gd3ONSe2 occupy the centers of one capped trigonal prism and two distorted octahedra of anions. Two octahedra, one with a cap, and a square antiprism can be seen for the anionic polyhedra of coordination for the Gd3+ cations in Gd3ONTe2. As main structural features $\rm^{1}_{\infty}${[ONGd3]4+} double chains, containing edge‐connected [NGd4]9+ and [OGd4]10+ tetrahedra, run along [010] in both compounds, but show two diverse detailed morphologies. A porous arrangement, which is obtained by a different linkage pattern of the light‐anion centered (Gd3+)4 tetrahedra can be detected in Gd3ONSe2, whereas the denser form of connectivity is seen in Gd3ONTe2. In both cases [OGd4]10+ tetrahedra represent the central components of the double chains leading to an ordering of the light anions in both structures as it is already known for Tb3ONSe2.