- Novel method for the production of copper(II) formates, their thermal, spectral and magnetic properties
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A new method for the synthesis of various types of copper(II) formates with Cu(NO3)2?3H2O and formic acid, orthorhombic (α) and monoclinic (β) modifications of anhydrous copper(II) formate, as well as Cu(HCOO)2?2H2O and Cu(HCOO)2?4H2O. The identity of the obtained compounds was confirmed by X-ray phase analysis, optical microscopy and thermogravimetry methods. It was shown that Cu(HCOO)2?4H2O can be used as a precursor for producing copper powders with particle size of the order of 150 nm. The results of investigation of vibration and absorption spectra of α and β modifications of anhydrous copper(II) formate are presented. Their magnetic behavior in the temperature interval 2–300 K was estimated, and comparative analysis of magnetic properties was carried out. First-principle calculations of electronic band structure for anhydrous α and β modifications were performed. The results obtained correspond to experimentally observed structural instability of β-Cu(HCOO)2, fundamental absorption edge enhancement during transition from α to β modification, and low-temperature ferromagnetic ordering in α-Cu(HCOO)2. Simulation for β modification is indicative of antiferromagnetic ordering of magnetic moments inside chains formed by copper-oxygen octahedra.
- Baklanova, I. V.,Chulkov, E. V.,Dyachkova, Т. V.,Gyrdasova, О. I.,Kellerman, D. G.,Krasil'nikov, V. N.,Tyutyunnik, А. P.,Zhukov, V. P.
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- Effect of pressure on two-dimensional Heisenberg antiferromagnet Cu(HCOO)2·4H2O
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The effect of pressure on two-dimensional Heisenberg antiferromagnet Cu(HCOO)2·4H2O has been investigated through X-ray diffraction, susceptibility and magnetization curve measurements. The pressurization induces the paramagnetic beh
- Tajiri,Matsumoto,Deguchi,Mito,Takagi,Moriyoshi,Itoh,Koyama
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p. e566-e568
(2008/10/09)
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- Double formates Ba2M(HCOO)6(H2O) 4 (M = Co, Ni, Cu, Zn): Crystal structures and hydrogen bonding systems
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The crystal structures of four members in the isomorphous series, Ba 2M(HCOO)6(H2O)4 (M=Co, Ni, Cu, Zn) are presented and thoroughly discussed. Discrepancies with a previous structural report on the Cu isolog [Z. Kristallogr. 110 (1958) 231] were cleared out through a re-refinement of the original data, the outcome of which definitely confirmed the present results. The strengths of the hydrogen bonds in the title compounds as deduced from the infrared wavenumbers of the uncoupled OD stretches of matrix-isolated HDO molecules are discussed in terms of the O w?O hydrogen bond lengths, the different hydrogen bond acceptor capabilities of the formate oxygen atoms and the weak Ba-OH2 interactions. The proton acceptor strength of the oxygen atoms is evaluated within the framework of the Brown's bond-valence theory. The intramolecular OH bond lengths are derived from the novel νOD vs. rOH correlation curve [J. Mol. Struct. 404 (1997) 63].
- Baggio,Stoilova,Polla,Leyva,Garland
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p. 173 - 180
(2007/10/03)
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- IR study of dibarium copper formate tetrahydrate
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The infrared spectra of Ba2Cu(HCOO)6·4H2O and its deuterated analogues have been recorded and the internal modes of the formate groups and water molecules are reported. Some of the internal formate modes (v4, v
- Stoilova,Koleva
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p. 291 - 295
(2007/10/03)
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