Browsing by Author "Schustereit, Tanja"
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Item Open Access Defect scheelite-type lanthanoid(III) ortho-oxomolybdates(VI) Ln0.667[MoO4] (Ln = Ce, Pr, Nd, and Sm) and their relationship to zircon and the NaTl-type structure(2011) Schustereit, Tanja; Müller, Sabine L.; Schleid, Thomas; Hartenbach, IngoThe rare-earth metal(III) ortho-oxomolybdates with the formula Ln0.667[MoO4] (Ln = Ce, Pr, Nd, and Sm) and defect scheelite-type structure crystallize in the tetragonal space group I41/a (a = 533–525, c = 1183–1158 pm) with four formula units per unit cell. The Ln3+ cations at Wyckoff position 4b exhibit a coordination sphere of eight oxygen atoms in the shape of a trigonal dodecahedron. The same site symmetry ( 4 ..) is observed for the tetrahedral oxomolybdate(VI) entities [MoO4]2–, since their central Mo6+ cation is situated at the 4a position. Due to this equal site multiplicity, the lanthanoid(III) cations have to be statistically under-occupied to maintain electroneutrality, thus a defect scheelite structure emerges. The partial structure of both the Ln3+ cations and the [MoO4]2– anions (if shrunk to their centers of gravity) can be best described as distorted diamond-like arrangements. Therefore, these two interpenetrating partial structures exhibit a similar setup as found in the zircon-type as well as in the NaTl-type structure.Item Open Access The defect scheelite-type lanthanum(III) ortho-oxidomolybdate(VI) La0.667[MoO4](2013) Schustereit, Tanja; Schleid, Thomas; Hartenbach, IngoThe crystal structure of La0.667[MoO4] in the Scheelite-type is described in that paper.