No abstract

Rb 2 SnCu 3 F 12 has been studied using synchrotron powder Xray diffraction, powder neutron diffraction and single crystal X-ray diffraction at a range of temperatures (100 -500 K). A broad but clear phase transition, possibly of re-entrant character, is found to occur in the powder form, whereas the corresponding transition is not seen in the single crystal.

The system Cs2−xRbxSnCu3F12 exhibits several different distorted variants of the kagome lattice, which are probed in detail by powder diffraction methods.

A series of new rare‐earth cadmium metal tellurite chlorides were synthesized by the salt flux technique and characterized by single‐crystal X‐ray diffraction. The new compounds CdSm2(TeO3)2Cl4 (I), CdEu2(TeO3)2Cl4 (II), and CdGd2(TeO3)2Cl4 (III), adopt layered structures corresponding to sequences of metal oxide [LnTeO3] and metal halide [Cd1–xCl3] layers. They expand the known family of 2D rare‐earth selenium oxyhalides into the realm of tellurium(IV) compounds and add a new targeted structure type involving rock salt slabs formed by edge‐sharing CdCl6 octahedra. The major differences in the structures of Se and Te compounds lie in the composition of the cationic slabs {[Ln11(SeO3)12]9+ vs. [Ln12(TeO3)12]12+} and symmetry (orthorhombic for selenites vs. tetragonal for tellurites).

Abstract:Two new members of the A2B′Cu3F12 family of kagome-related materials have been prepared, in order to further understand the crystal-chemical relationships, phase transitions and magnetic behaviour within this family of potentially frustrated S = ½ two-dimensional quantum magnets. Cs2TiCu3F12 adopts a crystal structure with the ideal kagome lattice topology (space group R3 ̅ m) at ambient temperature. Diffraction studies reveal different symmetry-lowering structural phase transitions in single crystal and polycrystalline forms at sub-ambient temperatures, with the single crystal form retaining rhombohedral symmetry OPEN ACCESSCrystals 2015, 5 227 and the powder form being monoclinic. In both cases, long-range antiferromagnetic order occurs in the region 16-20 K. Rb2TiCu3F12 adopts a distorted triclinic structure even at ambient temperatures.

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. [a] Cameron Black, [b] Lewis J. Downie [b] , Dmitry E. Sklovsky [a, c] , Peter S.Berdonosov [a] , Andrei V. Olenev [a, c] , Wuzong Zhou [b] , Philip Lightfoot [b] and Valery A.Dolgikh [a] similarities to those of known selenite analogs. We discuss the trends in similarities and differences in compositions and structural details between the Se and Te compounds; more members of the family are predicted.

A new organically-templated vanadium (III) fluoride, (NH 4 ) 2 (C 2 H 8 N)[V 3 F 12 ], has been prepared using an ionothermal approach. This compound has a unique layered structure featuring distorted S = 1 kagome planes separated by the cationic species. The compound exhibits magnetic frustration, with a canted antiferromagnetic ground state. On further cooling within the ground state a pronounced change in magnetisation kinetics is observed.The kagome lattice antiferromagnet is perhaps the most famous example of a geometrically-frustrated magnetic system 1,2 . The ideal kagome antiferromagnet consists of layers of corner-sharing equilateral triangles, with antiferromagnetically-coupled magnetic cations at each node. The inherent magnetic frustration in this system can be seen when one attempts to place 'spins' on each node of the triangles such that all near-neighbour interactions satisfy antiparallel (ie. antiferromagnetic, AFM) alignment. Not all preferred interactions can be satisfied simultaneously, leading to a vastly-increased number of compromise spin configurations of equally low energy. This frustration can result in various states that lie beyond the standard notions of long-range magnetic ordering (LRO) and spontaneous symmetry breaking, leading to either spin glass, spin ice and spin liquid states 3,4 . The inhibition of LRO is particularly acute in systems with 'quantum spins' (ie. J = S = ½ for the magnetic cations) for which quantum fluctuations combine with frustration to suppress LRO down to the lowest-accessible temperatures, in favour of quantum spin liquid ground states (QSLs).There is now growing evidence that these long-sought QSL states exist in recently studied S = ½ kagome antiferromagnets including herbertsmithite 5,6 and kapellasite 7 (both polymorphs of the composition ZnCu 3 (OH) 6 Cl 2 ) and the vanadium oxyfluoride [NH 4 8,9 . Analogous systems with S = 1 spins usually freeze into LRO states [10][11][12][13][14][15][16] (full details are given in ESI, Table S1) because here quantum fluctuations play a diminished role and probably more importantly, due to single ion anisotropy effects, which start to play a role for S > ½. Nevertheless, the diverse range of behaviour exhibited by the few examples so far, and the various theoretically proposed states for the related S = 1 triangular lattices 17,18 , demonstrates that further, chemically different, examples of S = 1 kagome magnets are of significant interest.In this paper we report a novel example of this family, in the compound (NH 4 ) 2 (C 2 H 8 N)[V 3 F 12 ] 1. This study forms part of our ongoing efforts to explore and understand the complex solvothermal/ionothermal chemistry of vanadium fluoride-based systems 8,[19][20][21] . Specifically, compound 1 was isolated by using identical chemistry ¶ to that in the preparation of the QSL compound DQ-VOF, except that the temperature of the reaction was increased from 170 to 210 C and the time was increased from 1 day to 5 days. Remarkably, this adjustment in reaction conditions pro...

Layers. -The new compounds CdSm 2(TeO3)2Cl4 (I), CdEu2(TeO3)2Cl4 (II), and CdGd2(TeO3)2Cl4 (III) are synthesized by the salt flux method from mixtures of LnOCl (Ln: Sm, Eu, Gd), TeO2, and CdCl 2 (850 C, 7 d). Their structures are determined by single crystal XRD. (I) and (II) crystallize in the tetragonal space group P4/nbm with Z = 12. (III) crystallizes in the tetragonal space I4/mcm with Z = 24. The compounds adopt layered structures corresponding to sequences of [LnTeO 3] and [Cd1-xCl3] layers. -(KHARITONOV, I. D.; CHARKIN, D. O.; BERDONOSOV*, P. S.; BLACK, C.; DOWNIE, L. J.; LIGHTFOOT, P.; DOLGIKH, V. A.; Eur.