The magnetic behaviour of cubic field 5T2g  terms in lower symmetry

Figgis, Brian N.; Lewis, J.; Mabbs, Frank E.; Webb, G. A.

doi:10.1039/j19670000442

Cited by 110 publications

(58 citation statements)

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“…1) and the magnetic susceptibilities follow Curie-Weiss behaviour, no maximum being observed. The higher temperature (80-300 K) magnetic data for these compounds were previously fitted to a crystal field model (23) in which magnetic moments are determined by the values of A, the spin-orbit coupling constant; v , the axial field splitting parameter; and k, the orbital reduction parameter (2, 6). We have extended the theoretical curves, calculated employing the parameters determined by fits to the high temperature data, into the low temperature region and find generally that the agreement with experiment is poor.…”

Section: Resultsmentioning

confidence: 99%

Low temperature magnetic and Mössbauer studies on anhydrous iron(II) sulfonates

Haynes¹,

Sams²,

Thompson³

1986

Can. J. Chem.

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Magnetic susceptibilities from 130 to 4.2 K are reported for a series of Fe(RSO3)2 compounds, where R is F, CF3, CH3, and p-CH3C6H4. The β form of Fe(CH3SO3)2 exhibits a maximum in susceptibility at approximately 22.5 K and a sharp drop in susceptibility below the maximum indicating a transition to a magnetically ordered state. None of the other compounds exhibit magnetic ordering although abnormally low magnetic moments down to 2.0 K are observed for α-Fe(CH3SO3)2. Variable-temperature Mössbauer studies on Fe(CF3SO3)2 and β- and α-Fe(CH3SO3)2 are reported and the magnitude of axial field splitting is estimated for these compounds. The first two have trigonally elongated FeO6 chromophores, whereas the third is trigonally compressed. The nature of the distortion in α-Fe(CH3SO3)2 is confirmed by magnetic perturbation Mössbauer studies. Spectra in applied fields of 4.50 and 5.63 T show a doublet–triplet pattern, with the triplet at higher energy, indicating a negative Vzz and an orbital singlet ground state.

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Section: Resultsmentioning

confidence: 99%

Low temperature magnetic and Mössbauer studies on anhydrous iron(II) sulfonates

Haynes¹,

Sams²,

Thompson³

1986

Can. J. Chem.

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“…1:1 compound Mn [2,3] Fe [3,5,6,7] Co [3,8] Ni [3] (1) M n [2] Fe (2II) ago by Real et al, [5] Haynes et al, [6] Figgis et al, [7] and Lloret et al, [3,8] but for a more accurate comparison with the ligand-deficient 1:1 compounds they were remeasured in our laboratory to lower temperatures. Figure 6 displays the results of the susceptibility measurements in the form of χ M vs. T, χ M -1 vs. T and χ M T vs. T plots, and Table 5 presents the results obtained upon fitting the data to the Curie-Weiss law χ M = C/(T -θ).…”

Section: :2 Compoundmentioning

confidence: 98%

Synthesis, Crystal Structure, and Thermal and Magnetic Properties of New Transition Metal–Pyrazine Coordination Polymers

2009

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The reaction of nickel thiocyanate with pyrazine in a 1:2 ratio leads to the new ligand-rich 1:2 (ratio metal/ligand) compound [Ni(SCN) 2 (pyrazine) 2 ] n (1), in which the metal atoms are coordinated by four N atoms of pyrazine ligands and two N atoms of thiocyanate anions in a slightly distorted octahedral arrangement. If an excess of the metal thiocyanate is used and the reaction is performed under solvothermal conditions, single crystals of the ligand-deficient 1:1 compounds [M(SCN) 2 (pyrazine) 2 ] n [M = Fe (2I), Co (3), Ni (4)] are obtained. Compound 2I is isotypic with [Mn(SCN) 2 (pyrazine)] n but different to 3 and 4, which are also isotypic. Investigations on the synthesis of these compounds reveal that only compound 4 can be prepared phase-pure in solution; all other ligand-deficient compounds are always contaminated with large amounts of the corresponding ligand-rich coordination polymers. In the crystal structures, the metal atoms

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“…Under the action of a trigonal crystal field, 5T2g splits into a 5A and 5E term, which may be split further by spin orbit coupling. The separation between 5E and 5A of 760 cm-1 was determined by susceptibility measurements in the range 80 K ^ T ^3 0 0 K [16], as well as being cal culated from Mößbauer data obtained at tempera tures ranging from 4 K to 300 K [17] where a spin orbit couphng constant of 100 cm-1 and 80 cm-1, respectively, was used. From susceptibility [18], free ion »cubic 'trig XLS (1st order) XLS H (2nd order) ---F ig.…”

Section: Discussionmentioning

confidence: 99%

Proton and Fluorine-Spin-Lattice Relaxation in Poly crystalline FeSiF₆ • 6 H₂O

Rager

1981

Zeitschrift Für Naturforschung A

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The proton and fluorine nuclear spin-lattice relaxation has been measured in FeSiFg • 6H2O in the temperature range 130 K ^ T ^ 420 K with standard pulse methods at 30 MHz. The relaxation times, T\(X H) and T\(19F), decrease with decreasing temperature according to the expression T\ = a (I) exp(-A/T) (I -1H, 19F). They show no significant dependence on the Larmor frequency. Thus, the unpaired Fe2+ electrons are mainly responsible for the proton and fluorine spin-lattice relaxation. The relaxation mechanism is described by an Orbach process. The ratio (19F)/7T i (*H) is relatively constant over the whole temperature range investigated. This is explained by the strong H ... F bonds in FeSiFß • 6H2O. The sharp increase of 71 i(1H) and T\ (19F) at 224 K is attributed to the phase transition, which probably alters the crystal field at the Fe2+ centers.

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The magnetic behaviour of cubic field 5T2g terms in lower symmetry

Cited by 110 publications

References 0 publications

Low temperature magnetic and Mössbauer studies on anhydrous iron(II) sulfonates

Low temperature magnetic and Mössbauer studies on anhydrous iron(II) sulfonates

Synthesis, Crystal Structure, and Thermal and Magnetic Properties of New Transition Metal–Pyrazine Coordination Polymers

Proton and Fluorine-Spin-Lattice Relaxation in Poly crystalline FeSiF₆ • 6 H₂O

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The magnetic behaviour of cubic field 5T2g terms in lower symmetry

Cited by 110 publications

References 0 publications

Low temperature magnetic and Mössbauer studies on anhydrous iron(II) sulfonates

Low temperature magnetic and Mössbauer studies on anhydrous iron(II) sulfonates

Synthesis, Crystal Structure, and Thermal and Magnetic Properties of New Transition Metal–Pyrazine Coordination Polymers

Proton and Fluorine-Spin-Lattice Relaxation in Poly crystalline FeSiF6 • 6 H2O

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Proton and Fluorine-Spin-Lattice Relaxation in Poly crystalline FeSiF₆ • 6 H₂O