Synthesis, crystal structure and magnetic properties of the open framework compound Co{sub 3}Te{sub 2}O{sub 2}(PO{sub 4}){sub 2}(OH){sub 4}

Journal Article · Tue Nov 15 00:00:00 EST 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.09.023· OSTI ID:21580080

Zimmermann, Iwan ^[1]; Johnsson, Mats ^[1]

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1. Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm (Sweden)

The new compound Co{sub 3}Te{sub 2}O{sub 2}(PO{sub 4}){sub 2}(OH){sub 4} was synthesized using hydrothermal techniques. It crystallizes in the monoclinic space group C2/m with the unit cell a=19.4317(10) A, b=6.0249(3) A, c=4.7788(2) A, {beta}=103.139(5){sup o}. The crystal structure is an open framework having chains of edge sharing [Co(1)O{sub 6}] octahedra. Other building blocks are [TeO{sub 3}(OH){sub 2}], [PO{sub 4}] and [Co({sub 2})O{sub 2}(OH){sub 4}] connected mainly via corner sharing. The -OH groups protrude into channels in the structure. The magnetic susceptibility measured from 2 to 300 K shows two broad anomalies at around 21 K and 4 K, respectively. The peak at {approx}20 K is ascribed to a two-dimensional antiferromagnetic ordering of linear [Co(1)O{sub 6}] chains coupled by interchain interaction via [PO{sub 4}] groups in the Co(1) sheets. The second transition at 4 K is ascribed to a second antiferromagnetic ordering of the moments of the Co(2) entities via super-super exchange involving [PO{sub 4}] and [TeO{sub 3}(OH){sub 2}] groups. This assignment is strongly supported by low-temperature heat capacity measurements indicating an entropy removal within the high-temperature transition of about twice the magnitude of the low-temperature transition. - Graphical Abstract: The new compound Co{sub 3}Te{sub 2}O{sub 2}(PO{sub 4}){sub 2}(OH){sub 4} has been synthesized using hydrothermal techniques. It crystallizes in the monoclinic space group C2/m. Building blocks are [Co(1)O{sub 6}], [TeO{sub 3}(OH){sub 2}], [PO{sub 4}] and [Co(2)O{sub 2}(OH){sub 4}]. The magnetic susceptibility shows two antiferromagnetic transitions at 21 K and 4 K, respectively. Highlights: > The first cobalt tellurium phosphate has been synthesized and structurally determined. > There are two antiferromagnetic orderings identified, one at 21 K and one at 4 K respectively. > A spin flop transition is observed at low temperatures.

• OSTI ID: 21580080
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 11; Other Information: DOI: 10.1016/j.jssc.2011.09.023; PII: S0022-4596(11)00516-0; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANTIFERROMAGNETISM
COBALT
HYDROXIDES
INTERACTIONS
MAGNETIC SUSCEPTIBILITY
MONOCLINIC LATTICES
PHOSPHATES
SPACE GROUPS
SPECIFIC HEAT
SYNTHESIS
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0400-1000 K
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELEMENTS
HYDROGEN COMPOUNDS
MAGNETIC PROPERTIES
MAGNETISM
METALS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PHYSICAL PROPERTIES
SYMMETRY GROUPS
TEMPERATURE RANGE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS