Two isostructural layered oxohalide compounds containing Mn{sup 2+}, Te{sup 4+} and Si{sup 4+}; crystal structure and magnetic susceptibility
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm (Sweden)
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany)
The new compounds Mn{sub 4}(TeO{sub 3})(SiO{sub 4})X{sub 2} (X=Br, Cl) were synthesized by solid state reactions in sealed evacuated silica tubes. The compounds crystallize in the monoclinic space group P2{sub 1}/m with the unit cell parameters a=5.5463(3) Å (5.49434(7) Å), b=6.4893(4) Å (6.44184(9) Å), c=12.8709(7) Å (12.60451(18) Å), β=93.559(5)° (94.1590(12)°) and Z=2 for the respective Br and Cl analogues. Manganese adopts various distorted coordination polyhedra; [MnO{sub 6}] octahedra, [MnO{sub 5}] tetragonal pyramids and [MnO{sub 2}X{sub 2}] tetrahedra. Other building blocks are [SiO{sub 4}] tetrahedra and [TeO{sub 3}] trigonal pyramids. The structure is made up from layers having no net charge that are connected via weak Van der Waal interactions. The layers that are parallel to (1 1 0) consist of two manganese oxide sheets which are separated by [SiO{sub 4}] tetrahedra. On the outer sides of the sheets are the [MnO{sub 2}X{sub 2}] tetrahedra and the [TeO{sub 3}] trigonal pyramids connected so that the halide ions and the stereochemically active lone pairs on the tellurium atoms protrude from the layers. Magnetic susceptibility measurements reveal a Curie law with a Weiss temperature of θ=−153(3) K for temperatures ≥100 K and indicate antiferromagnetic ordering at T{sub N} ∼4 K. Possible structural origins of the large frustration parameter of f=38 are discussed. - Graphical abstract: Table of contents caption. The new compounds Mn{sub 4}(TeO{sub 3})(SiO{sub 4})X{sub 2} (X=Br, Cl) are layered with weak Van der Waal interactions in between the layers. Manganese adopts various distorted coordination polyhedral, other building blocks are [SiO{sub 4}] tetrahedra and [TeO{sub 3}] trigonal pyramids. Magnetic susceptibility measurements indicate antiferromagnetic ordering at low temperatures and a large frustration parameter. - Highlights: • Two new isostructural oxohalide compounds are described. • The compounds are the first examples of oxohalides containing both Te{sup 4+} and Si{sup 4+}. • Both compounds display the unusual coordination polyhedron MnO{sub 2}X{sub 2} (X=Cl, Br). • The compounds are made up of charge neutral layers connected via weak interactions. • The compounds are antiferromagnetic and display a large frustration parameter.
- OSTI ID:
- 22443403
- Journal Information:
- Journal of Solid State Chemistry, Vol. 218; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANTIFERROMAGNETISM
CURIE-WEISS LAW
HALIDES
MAGNETIC SUSCEPTIBILITY
MANGANESE
MANGANESE IONS
MANGANESE OXIDES
MONOCLINIC LATTICES
SILICA
SILICATES
SILICON IONS
SILICON OXIDES
SPACE GROUPS
STEREOCHEMISTRY
TELLURIUM
TELLURIUM IONS
WEAK INTERACTIONS