Structure cristalline de la phase Yb0,5Eu0,5Fe2O4

Abstract

CYb, Eu)Fe204 crystallizes in space group R]m with hexagonal parameters a=b=3.486 and c= 24.92 A. The crystal structure has been determined by the heavy-atom method and Fourier synthesis.Least-squares refinement with anisotropic temperature factors yielded a final R value of 0.059. The rare-earth metals are octahedrally coordinated by six oxygen atoms and the iron atoms by five oxygen atoms at the apices of a trigonal bipyramid.

Reinvestigation of the LuFeO3(ZnO)m Homologous Series: Insights from Charge Distribution Analysis on the Effect of the Coordination Polyhedra Shape on the Cation Distribution

“…The number of M sites is K#1, and the number of crystallographically independent oxygen atoms is K#2. Lu is octahedrally coordinated by the (K#2)th oxygen, whereas the ith M site is coordinated by the oxygen atoms of types i!1, i, and i#1 [only O (1) 9), and also in a recent powder neutron di!raction study of the same compound, LuFeZnO (4).…”

Structures of LuFeO3(ZnO)m (m =1, 4, 5 and 6)

“…LuFeO3(ZnO) (Kimizuka & Takayama, 1981) is isostructural with the compounds In2ZnS4 (Lappe, Niggli, Nitsche & White, 1962) and YbFe204 (Kato, Kawada, Kimizuka & Katsura, 1975;Malaman et al, 1975). As for these compounds, the structures of LuFeO3(ZnO),,, ( Fig.…”

Synthesis, Crystal Structure and Charge Distribution of InGaZnO4. X-ray Diffraction Study of 20kb Single Crystal and 50kb Twin by Reticular Merohedry

“…InGaZnO 4 , the object of the present research, belongs to type-I, which includes also InFe 3+ 0.5 Fe 2+ 1.25 Si 0.25 O 4 (GÉRARDIN et al, 1980) and one of the two examples of Yb 2 Fe 3 O 7 reported to date (MALAMAN et al, 1976). Type-II is more extensively represented and includes YbFe 2 O 4 (KATO et al, 1975), Yb 0.5 Eu 0.5 Fe 2 O 4 (MALAMAN et al, 1975), InCuAlO 4 (GÉRARDIN et al, 1980, LuFe 2 O 4 (ISOBE et al, 1990), LuCoFeO 4 (ISOBE et al, 1990), LuFeZnO 4 (ISOBE et al, 1994CAVA et al, 1998;NESPOLO et al, 2000) and the other example of Yb 2 Fe 3 O 7 (KATO et al, 1976). In Table 8 the results of the CD analysis are given for these compounds.…”

“…9 0 0 42 489 494 4 -1 4 28 660 647 8 -1 2 42 448 450 7 0 1 29 201 198 2 -1 1 43 43 13 15 -2 2 29 187 185 2 0 2 43 0 16 1 -1 3 29 176 174 3 0 1 44 38 39 37 -3 4 29 163 153 9 0 0 45 309 311 3 0 4 29 163 143 4 -1 1 46 466 489 8 0 0 30 84 83 3 -1 2 30 63 61 5 -3 3 30 33 40 32 0 3 30 14 40 0 1 38 335 277 2 2 0 32 605 540 2 1 1 39 62 69 8 -2 -1 32 519 522 3 0 0 39 77 84 5 0 1 32 708 614 3 1 0 40 110 98 4 0 -2 32 549 585 2 0 -1 40 90 106 5 1 2 32 522 482 3 0 1 41 477 407 2 1 1 33 611 *Compounds with and without star (*) belong to type-I (regular bipyramids: the two apical M-O distances longer than the three basal ones) and type-II (distorted bipyramids: one of the apical M-O distances shorter and the other longer than the three basal ones) respectively. a ISOBE et al (1994);b ISOBE et al (1990); c GÉRARDIN et al (1980); d KATO et al (1975); e MALAMAN et al (1975); f KATO et al (1976);g MALAMAN et al (1976). implementation and usage of the PLATON software package. MN is indebted to Prof. Giovanni Ferraris (University of Torino, Italy) for discussions about the Charge Distribution method.…”