Crystal Structures of the Europium and Yttrium Hydroxychromate: Eu(OH)(CrO4) and Y(OH)(CrO4). Structural evolution as a function of the Ln3+ ionic radius.

Isabelle Gautier-Luneau (1) , Delphine Phanon

1 NEEL - OPTIMA - Optique et Matériaux

The Eu(OH)(CrO4) and Y(OH)(CrO4) compounds were obtained under hydrothermal conditions and characterized by single crystal X-ray diffraction analysis. They are isostructural and crystallize in the monoclinic system, space group P21/n (no. 14) with lattice parameters a = 8.278(1) Å, b = 11.400(2) Å, c = 8.393(1) Å, β = 93.76(2)°, V = 790.3(2) Å3, Z = 4, d = 4.79 g.cm-3 for Eu(OH)(CrO4) and a = 8.151(1) Å, b = 11.362(2) Å, c = 8.285(1) Å, β = 94.23(1)°, V = 765.2(2) Å3, Z = 4, d = 3.85 g.cm-3 for Y(OH)(CrO4). The [EuO8] polyhedra form infinite double chains along the a direction which are connected by common edges and corners. These double chains are related together in the two other directions via the [CrO4]2- tetrahedra to form a three-dimensional network in which channels appear parallel to the [100] direction. We examine the structural evolution, as a function of the Ln3+ ionic radius, in the series Ln(OH)(CrO4) compounds (with Ln = Nd, Eu, Gd, Tb, Er, Yb) and Y(OH)(CrO4). To determine the best coordination number of each lanthanide and yttrium ions, different calculations of bond valence sum have been realized.

Mots clés: Physical Sciences

Domaines: Physique Générale [physics.gen-ph]

Isabelle Gautier-Luneau, Delphine Phanon. Crystal Structures of the Europium and Yttrium Hydroxychromate: Eu(OH)(CrO4) and Y(OH)(CrO4). Structural evolution as a function of the Ln3+ ionic radius.. Journal of Inorganic and General Chemistry / Zeitschrift für anorganische und allgemeine Chemie, 2010, 636 (15), pp.2579. ⟨10.1002/zaac.201000261⟩. ⟨hal-00574816⟩