Synthesis, structure and magnetic properties of Na6Co2O6

Sofin, Mikhail; Peters, E.‐M.; Jansen, Martin

doi:10.1016/j.jssc.2004.03.036

Cited by 11 publications

(12 citation statements)

References 24 publications

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“…Furthermore, our present analysis shows a ferromagnetic spin alignment between the central Co III ions. This coupling is expected to be weaker [2] and a susceptibility study on Na 6 Co 2 O 6, [3] which contains Co 2 O 6 dimers that are exactly the inner parts of the tetramers, has confirmed that.…”

mentioning

confidence: 89%

Competing Magnetic Interactions in Na₁₀Co₄O₁₀, Studied by Neutron Diffraction

Stüßer

Sofin

Bircher

et al. 2006

Chemistry A European J

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Na(10)Co(4)O(10) was investigated by neutron powder diffraction at 230, 70, and 4 K. The crystal structure, determined previously by X-ray diffraction on single crystals, was confirmed. Na(10)Co(4)O(10) orders magnetically below 37 K. All observed magnetic reflections could be indexed by integers (hkl) with respect to the chemical unit cell and the magnetic propagation vector q=0. The refinement was performed in the Shubnikov space group C2/c and indicated a collinear antiferromagnetic spin structure. The determined spin arrangement is consistent with the magnetic intratetramer interactions suggested previously from the analysis of magnetic susceptibility data: the magnetic moments of the central Co(III) ions of the Co(4)O(10) tetramer lie parallel to each other and couple in an antiparallel fashion to the terminal Co(II) moments. The Rietveld analysis shows that the net moments of 0.64 mu(B) per tetramer form ferromagnetic layers parallel to the ab plane. Adjacent layers are coupled antiferromagnetically along c. The spins are aligned in the ac plane along the line connecting adjacent Co(II) and Co(III) ions of the tetramer. We have determined unusually low values for the ordered magnetic moments of 2.43(5) mu(B) and 2.11(6) mu(B) for Co(III) and Co(II), respectively. The occurrence of spontaneous magnetization below 37 K indicates a slight canting of 2.2 degrees of the antiferromagnetic structure. A representation analysis shows that a weak ferromagnetic component along b is compatible with the determined antiferromagnetic structure.

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mentioning

confidence: 89%

Competing Magnetic Interactions in Na₁₀Co₄O₁₀, Studied by Neutron Diffraction

Stüßer

Sofin

Bircher

et al. 2006

Chemistry A European J

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“…In 2004 Sofin , Peters und Jansen reported the synthesis, crystal structure and magnetic properties of Na 6 Co 2 O 6 = Na 3 CoO 3 48. The preparation was carried out by the azide/nitrate route described in Section E.1.…”

Section: F A3co3+o3mentioning

confidence: 99%

On the Crystal Chemistry of Alkali Metal Oxocobaltates

Müller‐Buschbaum¹

2012

Zeitschrift anorg allge chemie

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This Review on the crystal chemistry of oxocobaltates of alkali metals is presented according to the chemical composition. Classification of alkali oxocobaltates mainly depends on an increasing oxygen content of the compounds. Identical chemical compositions are sorted with increasing atomic numbers of the alkali metals. Cobalt is observed in the valence states Co+, Co2+, Co3+ and Co4+. No other metal shows such a close dependence of coordination and valence state. The oxygen coordination of Co+ in A3CoO2 (A = Na, K, Rb) and K2CsCoO2 is dumbbell‐shaped, the bond angles O–Co–Co being close to 180°. Coordination number two for the alkali metals (A) in these compounds is not less interesting, with the bond angles showing large deviations from a stretched O–A–O configuration. Cobalt in the valence state Co2+ (K2CoO2; Rb2Co2O3; Na4CoO3; Rb2K4Co2O5; K2Na4Co2O5; RbNa7Co2O6; Na10Co4O9) prefers a trigonal planar coordination. There is only one compound (Na7Co2O6) showing mixed valences Co2+/Co3+ together with a triangular coordination. Tetrahedral coordination is typical for cobalt in the valence state Co3+ (K/RbCoO2; Na6Co2O6; Na5CoO4; Na2Li3CoO4). Few compounds (K/Cs/Rb2CoO3; Na4CoO4; Li8CoO6; K6Co2O7) show Co4+ beside Co3+ in tetrahedral coordination. A small amount of oxocobaltates show octahedral coordination with cobalt in the valence states Co3+ (LiCoO2; NaCoO2) and higher (NaCo2O4; K4Co7O14). Finally, one mixed alkali rare earth oxocobaltate, Nd18Li8Co4O39, is presented. Several oxocobaltates reported in the ICSD database show cobalt on different point positions. In these cases it is of interest to calculate Madelung Parts of Lattice Energie (MAPLE) established by Rudolf Hoppe. MAPLE allows calculation of the differences between the Coulomb‐terms of the lattice energy, which exclusively depends on the valences of cobalt on different point positions. In all comparable cases identical positional configurations of the atoms prevent influences of the repulsion term of the lattice energy. The energy balance therefore exclusively depends on the valence states of cobalt and its distribution on the point positions, with Rb2Co2O3, Na4CoO3, Na8Co2O7, Na10Co4O9, and Na10Co4O10 being examples.

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“…The title compound was prepared via the azide/nitrate route [24,25] [23]. In a flow of dried argon the following temperature program was applied: 25 Ǟ 260°C (100°C/h); 260 Ǟ 380°C (5°C/h); 380 Ǟ 500°C (20°C/h) and subsequent annealing for 75 h at 500°C.…”

Section: Synthesis Of Rb 6 Mn 2 Omentioning

confidence: 99%

Synthesis and Properties of Rb₆Mn₂O₆

Pfeiffer

Fischer

Jansen

2008

Zeitschrift anorg allge chemie

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Rb 6 Mn 2 O 6 was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursors (Mn 3 O 4 , RbN 3 and RbNO 3 )were heated in a special regime up to 500°C and annealed at this temperature for 75 h in silver crucibles. Single crystals have been grown by annealing a mixture with a slight excess of rubidium components at 450°C for 500 h. According to the single crystal structure analysis, Rb 6 Mn 2 O 6 is isotypic to K 6 Mn 2 O 6 , and crystallizes in the monoclinic space group P2 1 /c with a ϭ 6.924(1) Å , b ϭ

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Synthesis, structure and magnetic properties of Na6Co2O6

Cited by 11 publications

References 24 publications

Competing Magnetic Interactions in Na₁₀Co₄O₁₀, Studied by Neutron Diffraction

Competing Magnetic Interactions in Na₁₀Co₄O₁₀, Studied by Neutron Diffraction

On the Crystal Chemistry of Alkali Metal Oxocobaltates

Synthesis and Properties of Rb₆Mn₂O₆

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Synthesis, structure and magnetic properties of Na6Co2O6

Cited by 11 publications

References 24 publications

Competing Magnetic Interactions in Na10Co4O10, Studied by Neutron Diffraction

Competing Magnetic Interactions in Na10Co4O10, Studied by Neutron Diffraction

On the Crystal Chemistry of Alkali Metal Oxocobaltates

Synthesis and Properties of Rb6Mn2O6

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Product

Resources

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Competing Magnetic Interactions in Na₁₀Co₄O₁₀, Studied by Neutron Diffraction

Competing Magnetic Interactions in Na₁₀Co₄O₁₀, Studied by Neutron Diffraction

Synthesis and Properties of Rb₆Mn₂O₆