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Crystal Structures of the Europium and Yttrium Hydroxychromates Eu(OH)(CrO 4 ) and Y(OH)(CrO 4 ); Structural Evolution as a Function of the Ln 3+ Ionic Radius
Author(s) -
Pha Delphine,
GautierLuneau Isabelle
Publication year - 2010
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201000261
Subject(s) - ionic radius , isostructural , yttrium , crystallography , europium , lanthanide , monoclinic crystal system , crystal structure , valence (chemistry) , ion , bond length , chemistry , coordination number , hydrothermal synthesis , materials science , hydrothermal circulation , oxide , organic chemistry , seismology , geology
The compounds Eu(OH)(CrO 4 ) and Y(OH)(CrO 4 ) 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 P 2 1 / 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) Å 3 , Z = 4, d = 4.79 g · cm –3 for Eu(OH)(CrO 4 ) and a = 8.151(1) Å, b = 11.362(2) Å, c = 8.285(1) Å, β = 94.23(1)°, V = 765.2(2) Å 3 , Z = 4, d = 3.85 g · cm –3 for Y(OH)(CrO 4 ). The [EuO 8 ] 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 by the [CrO 4 ] 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 Ln 3+ ionic radius, in the series Ln (OH)(CrO 4 ) compounds (with Ln = Nd, Eu, Gd, Tb, Er, Yb) and Y(OH)(CrO 4 ). To determine the best coordination number of each lanthanide and yttrium ions, different calculations of bond valence sum were realized.