Validating the model of a (3 + 1)-dimensional incommensurately modulated structure as generator of a family of compounds for the Eu₂(MoO₄)₃scheelite structure

Abstract

To cite this Article Martinez-Garcia, J., Arakcheeva, A., Pattison, P., Morozov, V. and Chapuis, G.(2009) 'Validating the model of a (3 + 1)-dimensional incommensurately modulated structure as generator of a family of compounds for the Eu 2 (MoO 4 ) 3 scheelite structure ',Philosophical Magazine Letters,89:4,[257][258][259][260][261][262][263][264][265][266] To link to this Article: DOI: 10.1080/09500830902802657 URL: http://dx.doi.org/10.1080/09500830902802657Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden.The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. Vol. 89, No. 4, April 2009, 257-266 Validating the model of a (3 Y 1)-dimensional incommensurately modulated structure as generator of a family of compounds for the Eu 2 (MoO 4 ) 3 scheelite structure The previously proposed model postulating that the incommensurately modulated KNd(MoO 4 ) 2 structure can act as a generator of the scheelite family members is validated here by refining the crystal structure of europium molybdate, Eu 2 (MoO 4 ) 3 . The initial structural model was derived from the superspace characteristics of KNd(MoO 4 ) 2 and the predicted parameters used in the simulation of Eu 2 (WO 4 ) 3 . The refinement was performed using both superspace and traditional supercell approaches in superspace group I2/b(0)00 and space group A2/a, respectively. The results obtained by both approaches are in excellent agreement and coincide with those reported in the literature. Philosophical Magazine Letters

The luminescence of NaxEu3+(2−x)/3MoO4scheelites depends on the number of Eu-clusters occurring in their incommensurately modulated structure

“…According to the scheme proposed for SRC, 14 the I2/b(ab0)00 (3 + 1)D superspace group has been applied here for all other incommensurately modulated structures and earlier for Eu 3+ 2/3 MoO 4 . 17 The phase with x ¼ 0.134 has been refined along with 6% of an additional phase with x ¼ 0.015. The crystallographic data are shown in Table 1.…”

Crystal Structure, Vibrational, Spectroscopic and Thermochemical Properties of Double Sulfate Crystalline Hydrate [CsEu(H2O)3(SO4)2]·H2O and Its Thermal Dehydration Product CsEu(SO4)2

“…Self-activated phosphors are characterized by an almost complete absence of structural defects, and the precise determination of the crystal structure makes it possible to evaluate the relations between the Eu 3+ ion coordination in the lattice and spectroscopic characteristics of the compound. Simple europium stoichiometric compounds with tetrahedral MO 4 units, where M = Mo, W and S, were thoroughly studied and their applicability as highly efficient polyfunctional materials was shown [54][55][56][57][58][59][60][61][62][63][64][65][66][67]. At the same time, the properties of complex compounds of monovalent cations and rare-earth elements with tetrahedral anions are presented quite sporadically in the literature [37,[48][49][50][51]53,[68][69][70][71][72].…”

Crystal Structure and Luminescent Properties of R2–xEux(MoO4)3 (R = Gd, Sm) Red Phosphors

“…A comprehensive structural study of the R 2 (MoO 4 ) 3 molybdates was initially reported by Nassau et al Later, the structural data on different modifications of the R 2 (MoO 4 ) 3 molybdates were revised, − and it was shown that the stability of different crystal forms depends on both the rare earth element and thermal treatment conditions. Generally, these compounds can be divided into two groups, having scheelite-type and non-scheelite structures.…”

“…Generally, these compounds can be divided into two groups, having scheelite-type and non-scheelite structures. Among the scheelite-type R 2 □(MoO 4 ) 3 (where □ indicates a cation vacancy) structures, four variants are known with random or ordered distribution of the cations and vacancies: (1) tetragonal (space group (SG) I 4 1 / a ); − (2) monoclinic (SG C 2/ c ) with the La 2 (MoO 4 ) 3 -type structure; (3) monoclinic (SG C 2/ c ) − with the Eu 2 (WO 4 ) 3 -type structure (usually termed α-phases) (Figure a); and (4) monoclinic with the incommensurately modulated Pr 2 (MoO 4 ) 3 -type structure (superspace group (SSG) I 2/ b (αβ0)­00) . The ordering of cation vacancies in the scheelite-type R 2 □(MoO 4 ) 3 compounds depends on the R element.…”