Zur Kristallstruktur der Cyanoelpasolithe [N(CH3)4]2CsCo(CN)6 und [H3NCH3]2NaFe(CN)6 / Concerning the Crystal Structures of the Cyano-Elpasolites [N(CH3)4]2CsCo(CN)6 and [H3NCH3]2NaFe(CN)6

Peschel, S.; Babel, D.

doi:10.1515/znb-1994-1011

Cited by 10 publications

(2 citation statements)

References 2 publications

(2 reference statements)

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“…We have not explored this point further in our current study, but note that a higher T c would correspond to a stronger ferroquadrupolar coupling constant J, which in turn is to be expected given the reduced unit cell constants relative to We turn now to the related issue of ferrooctupolar order in the compositional family [NMe 4 ] 2 B[Co(CN) 6 ] (B = K, Rb, Cs). All but the K-containing member of this specific family have been characterized previously [60][61][62], and the corresponding hexacyanoferrates are known for all three B-site cations [45,63] [45]; at higher temperatures our data were consistent with the aristotypic Fm3m structure as reported for the hexacyanoferrate in [45]. Full details of our refinements are given as electronic supplementary material, but we show representative fits and structural models for data collected at 300 and 400 K in figure 4.…”

Section: (D) Monte Carlo Simulationssupporting

confidence: 78%

Ferroic multipolar order and disorder in cyanoelpasolite molecular perovskites

Coates¹,

Gray²,

Bulled³

et al. 2019

Phil. Trans. R. Soc. A.

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We use a combination of variable-temperature high-resolution synchrotron X-ray powder diffraction measurements and Monte Carlo simulations to characterize the evolution of two different types of ferroic multipolar order in a series of cyanoelpasolite molecular perovskites. We show that ferroquadrupolar order in [C 3 N 2 H 5 ] 2 Rb[Co(CN) 6 ] is a first-order process that is well described by a four-state Potts model on the simple cubic lattice. Likewise, ferrooctupolar order in [NMe 4 ] 2 B[Co(CN) 6 ] (B = K, Rb, Cs) also emerges via a first-order transition that now corresponds to a six-state Potts model. Hence, for these particular cases, the dominant symmetry breaking mechanisms are well understood in terms of simple statistical mechanical models. By varying composition, we find that the effective coupling between multipolar degrees of freedom—and hence the temperature at which ferromultipolar order emerges—can be tuned in a chemically sensible manner. This article is part of the theme issue ‘Mineralomimesis: natural and synthetic frameworks in science and technology’.

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Section: (D) Monte Carlo Simulationssupporting

confidence: 78%

Ferroic multipolar order and disorder in cyanoelpasolite molecular perovskites

Coates¹,

Gray²,

Bulled³

et al. 2019

Phil. Trans. R. Soc. A.

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“…Gruppe±Untergruppe-Beziehungen fu È r verzerrte Hettotypen des Elpasoliths und einige entsprechende Cyano-Derivate. (NMe 4 ) 2 RbFe(CN) 6 (Schwarten et al, 1997), (NMe 4 ) 2 RbCo(CN) 6 (Ziegler et al, 1991), (NMe 4 ) 2 CsCo(CN) 6 (Peschel & Babel, 1994), (NMe 4 ) 2 KCr(CN) 6 (Schwarten & Babel, 2000) und Cs 2 KFe(CN) 6 (Peschel et al, 2000). P4amnc fu È r Cs 2 LiCr(CN) 6 (Chowdhury et al, 1977) wird von Ryan (1978) angezweifelt, es ko È nnten P12 1 an1-Zwillinge sein.…”

Section: Abbildungunclassified

Symmetrieverwandtschaften bei Varianten des Perowskit-Typs

Böck

Müller

2002

Acta Crystallogr Sect B

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The relationships among the huge number of derivative structures of the perovskite type are rationalized in a concise manner using group-subgroup relations between space groups. One family tree of such relations is given for perovskites having tilted coordination octahedra. Further group-subgroup relations are concerned with distortions of the octahedra, such as Jahn-Teller distortions or with atoms shifted from the octahedron centres. In these cases, the space-group symmetry reductions must allow site symmetry reductions of the occupied sites in the perovskite structure. On the other hand, subgroups in which the perovskite sites split into different independent sites are necessary for derivative structures with atom substitutions, such as in the elpasolites A(2)EMX(6). In addition, substitutions and distortions can be combined in adequate subgroups. Substitutions may also involve the occupation of atom sites of perovskite by molecular groups such as N(CH(3))(4)(+) or other organic cations, or by molecules like acetonitrile. If they are ordered, their molecular symmetry requires further space-group symmetry reductions. The anions can be replaced by cyanide ions or by NO(2)(-) ions; space-group symmetry then depends on the temperature-dependent degree of order. The relationships can be used to predict if and what kind of twinning may occur in phase transitions and whether second-order phase transitions are possible.

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Hybrid Cyanide Perovskites

2020

Hybrid Organic‐Inorganic Perovskites

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Zur Kristallstruktur der Cyanoelpasolithe [N(CH₃)₄]₂CsCo(CN)₆ und [H₃NCH₃]₂NaFe(CN)₆ / Concerning the Crystal Structures of the Cyano-Elpasolites [N(CH₃)₄]₂CsCo(CN)₆ and [H₃NCH₃]₂NaFe(CN)₆

Abstract: Hexacyanometallates(III),

Cited by 10 publications

References 2 publications

Ferroic multipolar order and disorder in cyanoelpasolite molecular perovskites

Ferroic multipolar order and disorder in cyanoelpasolite molecular perovskites

Symmetrieverwandtschaften bei Varianten des Perowskit-Typs

Hybrid Cyanide Perovskites

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