Iron(II) phosphonates: a new series of molecule-based weak ferromagnets
被引:35
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Altomare, A
Bellitto, C
论文数: 0引用数: 0
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机构:CNR, Ist Chim Mat, I-00016 Monterotondo, Roma, Italy
Bellitto, C
Ibrahim, SA
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机构:CNR, Ist Chim Mat, I-00016 Monterotondo, Roma, Italy
Ibrahim, SA
Mohammed, MR
论文数: 0引用数: 0
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机构:CNR, Ist Chim Mat, I-00016 Monterotondo, Roma, Italy
Mohammed, MR
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Rizzi, R
机构:
[1] CNR, Ist Chim Mat, I-00016 Monterotondo, Roma, Italy
[2] Univ Bari, Dipartimento Geomineral, CNR, Ist Ric Sviluppo Metodol Cristallog, I-70125 Bari, Italy
[3] Univ Assiut, Fac Sci, Dept Chem, Assiut, Egypt
来源:
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
|
2000年
/
21期
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D O I:
10.1039/b003171m
中图分类号:
O61 [无机化学];
学科分类号:
070301 ;
081704 ;
摘要:
The complexes Fe[CH3PO3].H2O, Fe-2[O3P(CH2)(2)PO3]. 2H(2)O and Fe-2[O3P(CH2)(2)PO3] were synthesized and characterized by thermogravimetric analysis and UV-visible and infrared spectroscopy and their magnetic properties studied using a superconducting quantum interference device magnetometer. Preliminary X-ray single-crystal data suggest for Fe[CH3PO3].H2O a lamellar structure similar to that observed in Cd[CH3PO3].H2O. The structure of cadmium phosphonate consists of alternating inorganic and organic layers, with the metal ion octahedrally co-ordinated by five oxygens from phosphonate and one from a water molecule. The inorganic layers are then separated by bilayers of methyl groups, and van der Waals contacts are established between them. In Fe-2[O3P(CH2)(2)PO3]. 2H(2)O a pillared structure similar to that found in the corresponding zinc(II) ethylenebis(phosphonates) is suggested. All the compounds reported contain Fe-II in the d(6) (S=2) high-spin electronic configuration, as determined from magnetic measurements in the high temperature region. Below 100 K the effective magnetic moment of Fe[CH3PO3].H2O decreases down to 30 K, then rises rapidly to a maximum at 24 K, and decreases again. The 3-D long-range antiferromagnetic order, defined as the temperature of the onset of the magnetization, has been located at T-N=25 K. Similar behavior has been observed in Fe-2[O3P(CH2)(2)PO3]. 2H(2)O. Below the critical temperature, T-N, both compounds behave as a "weak ferromagnet". After dehydration Fe-2[O3P(CH2)(2)PO3]. 2H(2)O loses the water molecules, and its magnetic behavior changes drastically in the low temperature region. The magnetic data at low temperatures of anhydrous Fe-2[O3P(CH2)(2)PO3] are consistent with a magnetically disordered ground state, possibly a spin-glass like state.
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页码:3913 / 3919
页数:7
相关论文
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[1]
Alberti G, 1996, COMPREHENSIVE SUPRAM, P151
[2]
Bellitto C, 1999, MATER RES SOC SYMP P, V547, P487