Ceramics-Silikáty 49, (3) 181 - 187 (2005) |
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SYNTHESIS, STRUCTURAL AND MAGNETIC PROPERTIES OF TM²⁺₂[MoIV(CN)₈]·nH₂O
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Mitróová Zuzana 1, Mihalik Marián 1, Zentko Anton 1,
Bokor Mónika 2,
Kamarás Katalin 2,
Kavečanský Viktor 1,
Kováč Jozef 1,
Csach Kornel 1,
Trpčevská Jarmila 3
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1 Institute of Experimental Physics SAS, Watsonova 47, 043 53 Košice, Slovakia
2 Research Institute for Solid State Physics and Optics of the Hungarian Academy of Science,
P.O. Box 49, H-1525 Budapest, Hungary
3 Technical University of Košice, Letná 9, 042 00 Košice, Slovakia
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Keywords: Octacyanocomplexes, Crystal structure, NMR spectroscopy, Magnetic properties
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Octacyanomolybdates (OCMs) TM²⁺₂[Mo(CN)₈]·nH₂O, where TM is Mn, Fe, Co, Ni, Cu were synthesised and characterised
by IR spectroscopy and UV-VIS spectroscopy. The UV-VIS spectrum showed the intervalence charge transfer (IVCT) band
between MoIV-CN-CuII and MoV-CN-CuI around 510 nm. Studied OCMs adopt tetragonal crystal structure. The ¹H NMR signals
reflect the magnetic moment of the TM²⁺ ions (μP). The decay rates of free induction decay (FID) signals increase as μP
and the applied static rf -field increases. The spin - lattice relaxation times at 27.7 MHz vary from 0.0187 ms (Mn) up to
0.45 ms (Cu). Magnetization measurements indicate long-range magnetic ordering of Mn- and Co- OCMs with the Curie temperature
Tc = 4 K. The remaining OCMs (TM is Fe, Ni, Cu) are paramagnetic down to T=1.9 K. |
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