Isotope effects measured by mössbauer spectrometry in ferrous oxalate and perchlorate

Brunot, B.

doi:10.1016/0009-2614(74)85124-9

Cited by 14 publications

(9 citation statements)

References 5 publications

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“…The change in the 57 Fe Mössbauer quadrupole splitting by more than a factor 2 has been first observed by Dézsi 6 ](ClO 4 ) 2 around 237 K with 30 K broad temperature range of phase co-existence [1]. The effect was the same for either increasing or decreasing the temperature.…”

Section: Introductionmentioning

confidence: 78%

“…An isotope effect of the transition temperature T t was observed by Brunot [6]. On heating the samples, T t = 257 K and 261 K were measured for the hydrogenated and the deuterated samples, respectively, while on cooling down, the respective values of T t = 246 K and 250 K were found [6]. This author reported no co-existence of the high-and low-temperature phases.…”

Section: Introductionmentioning

confidence: 88%

“…High-magnetic-field Mössbauer measurements of Spiering et al evidenced the point symmetry of the Fe 2+ ion in the low-temperature phase to be C 2h , a subgroup of the pure trigonal group D 3d [5]. An isotope effect of the transition temperature T t was observed by Brunot [6]. On heating the samples, T t = 257 K and 261 K were measured for the hydrogenated and the deuterated samples, respectively, while on cooling down, the respective values of T t = 246 K and 250 K were found [6].…”

Section: Introductionmentioning

confidence: 93%

“…The orbital-ground-state transformation in the high-spin Fe 2+ co-ordination compound [Fe(H 2 O) 6 ](ClO 4 ) 2 was the subject of extensive studies from the mid-1960s to the mid1970s. The change in the 57 Fe Mössbauer quadrupole splitting by more than a factor 2 has been first observed by Dézsi 6 ](ClO 4 ) 2 around 237 K with 30 K broad temperature range of phase co-existence [1].…”

Section: Introductionmentioning

confidence: 99%

“…When increasing the temperature, T t = 279 K and 285 K were measured for the hydrogenated and the deuterated samples, respectively, while on cooling down, the respective values of T t = 272 K and 281 K were found [7]. 6 ](BF 4 ) 2 showed a co-existence of the two phases between 273 K and 283 K on cooling down the compound, while the same transition took place by about 12 K higher temperatures on warming it up [9]. The latter authors concluded that the co-existence of the two phases over several Kelvin and the broad hysteresis indicated a first-order phase transition.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Nuclear resonant scattering evidence of the phase co-existence during structural phase transformation in [Fe(H2O)6](ClO4)2

Vankó

Bottyán

Deák

et al. 2005

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Nuclear resonant scattering evidence of the phase co-existence during structural phase transformation in [Fe(H2O)6](ClO4)2

Vankó

Bottyán

Deák

et al. 2005

Journal of Alloys and Compounds

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Structural Phase Transitions in Zinc(II) Perchlorate Hexahydrate

Borzęcka-Prokop¹,

Hodorowicz²

1995

Cryst. Res. Technol.

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Structural Phase Transitions in Zinc(I1) Perchlorate HexahydratePhase transitions in zinc perchlorate hexahydrate are studied by X-ray powder diffraction method. Structural changes in the vicinity of transitions detected at 364.5 K and 256.3 K are characterized, At the former the orthorhombic Pmn2, phase transforms into the Pmna one (a = 7.812(1), b = 13.518 (3) and c = 5.279(1) 8, at 348.6 K). The latter involves changes of the orthorhombic unit cell (a = 7.7922(9), b = 13.537(2) and c = 5.0588(6) 8, at 251.0 K). Temperature dependence of lattice parameters in the range of 180 to 363.3 K are presented.

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Electric Field Gradient in Ferrous Oxalate Dihydrate

Śedzińska

1987

Physica Status Solidi (b)

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Below the NBel temperature the ferrous oxalate dihydrate is characterized by a large electric quadrupole interaction comparable with the dipole magnetic one /1 to 4/. This implies an ambiguity in the determination of the asymmetry parameter p and the angles (8 , (b )describing the orientation of the internal magnetic field (HefJ with respect to the principal axes of the electric field gradient (EFG) /5, 6/. Mossbauer spectra of oc -FeC2O4-2D20 have been measured at 300 and 4.2 K in /4/ to study the deuterium isotope effect. The analysis of the spectrum a t 4.2 K gives the ambiguity region: 76 O< 8 < 90°, Oo< (9 < 18O, and 0.46 < ' 1 c 0.72./7/ has shown, below TN = (16 11' deviation of the magnetic moment direction from the crystal b-axis. Each Fe ion in w-FeC2O4. 2D20 (space group C%/c) is located a t the centre of a distorted octahedron with vertices occupied by four O2 ions of the oxalate groups and arranged in a rectangle with the longer edges parallel to the b-axis. The two other 0 ions, belonging to the water molecules, are situated along the a-axis. To a good approximation, the orthorhombic symmetry of the octahedron may be assumed with the z, y, x axes parallel to the a , b, and c' = c sin B macroscopic axes, respectively. A comparison of the angular ambiguity region with the neutron diffraktion result implies that the Vxx axis of the EFG tensor is directed along the b-axis. Based on the above data it is difficult to decide the orientation of the remaining EFG axes. Therefore the following two possibilities were taken into account in calculations using a computer program /a/: (ii) Vzz parallel to the c' -axis (perpendicular to the a-b plane). Then 8 = = (84 2 1)' and (9 = (11 ? 1)'. The best fit has been obtained for ' 2 = 0.58 2 0.2.On the other hand, the recent neutron diffraction study of a -FeC204-2D20 1) K, the collinear magnetic structure with

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Isotope effects measured by mössbauer spectrometry in ferrous oxalate and perchlorate

Cited by 14 publications

References 5 publications

Nuclear resonant scattering evidence of the phase co-existence during structural phase transformation in [Fe(H2O)6](ClO4)2

Nuclear resonant scattering evidence of the phase co-existence during structural phase transformation in [Fe(H2O)6](ClO4)2

Structural Phase Transitions in Zinc(II) Perchlorate Hexahydrate

Electric Field Gradient in Ferrous Oxalate Dihydrate

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