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Hydrothermal Synthesis, X‐Ray Structure and Complex Magnetic Behaviour of Ba 4 (C 2 O 4 )Cl 2 [{Fe(C 2 O 4 )(OH)} 4 ]
Author(s) -
Price Daniel J.,
Tripp Scott,
Powell Annie K.,
Wood Paul T.
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010105)7:1<200::aid-chem200>3.0.co;2-x
Subject(s) - oxalate , antiferromagnetism , crystallography , tetragonal crystal system , magnetization , chemistry , magnetic susceptibility , muon spin spectroscopy , crystal structure , nuclear magnetic resonance , materials science , condensed matter physics , inorganic chemistry , superconductivity , magnetic field , physics , quantum mechanics
Hydrothermal reaction of iron( III ) chloride, barium chloride and sodium oxalate in a narrow stoichiometry range produces the title compound Ba 4 (C 2 O 4 )Cl 2 [{Fe(C 2 O 4 )(OH)} 4 ] ( 1 ). This new iron( II ) oxalate crystallises in the tetragonal space group P 4 2 / mnm: a =13.811(3), c =7.026(2) Å. The structure consists of parallel chains of μ 2 ‐hydroxy‐bridged iron( II ) ions. These are connected by bridging oxalates to form an anionic framework with large channels that contain the remaining barium, chloride and oxalate counter ions. Magnetisation studies on an oriented single crystal of 1 revealed a magnetic phase transition at 32 K and a strong easy‐plane anisotropy at all temperatures. Above T c the compound behaves as an S =2 XY antiferromagnetic chain, showing a broad maximum in the susceptibility at about 70 K. We determined the intrachain coupling J and the interchain coupling J′ to be −7 cm −1 and ±0.4 cm −1 , respectively. The low‐temperature phase is an ordered antiferromagnetic state. Zero‐ and longitudinal‐field muon spin‐rotation/relaxation studies support this interpretation; below T c oscillations in the muon spin‐autocorrelation function are observed giving unambiguous evidence for a non‐zero sublattice magnetisation and proof of a long‐range magnetically ordered state.