Ionothermal Synthesis, Structures, and Magnetism of Three New Open Framework Iron Halide-Phosphates.
Inorg Chem
; 58(19): 13203-13212, 2019 Oct 07.
Article
em En
| MEDLINE
| ID: mdl-31539232
ABSTRACT
A set of different open framework iron phosphates have been synthesized ionothermally using a task-specific ionic liquid, 1-butyl-4-methylpyridinium hexafluorophosphate, that acts in the synthesis as the reaction medium and mineralizer (NH4)2Fe2(HPO4)(PO4)Cl2F (1) and K2Fe2(HPO4)(PO4)Cl2F (2) exhibit similar composition and closely related structural features. Both structures consist of {Fe2(HPO4)(PO4)Cl2F}2- macroanions and charge balancing ammonium or potassium cations. Their open framework structure contains layers and chains of corner-linked {Fe(1)O2Cl4} and {Fe(2)F2O4} octahedra, respectively, interconnected by PO4 tetrahedra forming 10-ring channels. KFe(PO3F)F2 (3) is built up by {Fe[(PO3F)4/3F2/2]}{Fe(PO3F)2/3F2/2F2} layers separated by K+ cations. Chains of alternating {FeF2O4} and {FeO2F4} octahedra, which are linear for 1 but undulated for 2, are linked to each other via corner-sharing {PO3F} tetrahedra with the fluorine pointing into the interlayer space. The compounds were characterized by means of single crystal and powder X-ray diffraction, infrared spectroscopy, and magnetic measurements. 1 reveals a strong ground state spin anisotropy with a spin 5/2 state and a magnetic moment of 5.3 µB/Fe3+. Specific heat and magnetic data unveil three magnetic transitions at 95, 50, and 3.6 K. Compound 2 has a very similar crystal structure as compared to 1 but exhibits a different magnetic behavior a slightly lower magnetic moment of 4.7 µB/Fe3+ and a magnetic transition to a canted antiferromagnetic state below 90 K. Compound 3 exhibits typical paramagnetic behavior close to room-temperature (5.71 µB/Fe3+). There are no clear indications for a phase transition down to 2 K despite strong antiferromagnetic spin-spin interactions; only a magnetic anomaly appears at 50 K in the zero-field cooled data.
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Coleções:
01-internacional
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MEDLINE
Idioma:
En
Revista:
Inorg Chem
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Alemanha