A new example of an arrangement of antiphase domains: investigation by neutron diffraction of deuterated manganese fluosilicate

Chevrier, G.

doi:10.1107/s0108768190012757

Cited by 23 publications

(9 citation statements)

References 8 publications

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“…The fluorosilicates of Mg, Fe and Mn belong to the second group. The presence of superstructure reflections at room temperature for these crystals, in contradiction to the structural model given by Hamilton [27] and Syoyama and Osaki [28], was the reason for Chevrier et al [31,32,[35][36][37][38] introducing the space group P 3 for the proper treatment. Chevrier et al [31,32,[35][36][37][38] also assumed two types of domain with different orientations of complex ions, connected by a pseudomirror plane (11.0).…”

Section: In These Compounds Complex A[h 2 O] 2+mentioning

confidence: 74%

“…6 ions and [BF 6 ] 2− octahedra form a rhombohedrally distorted CsCl-type lattice and can be distributed between two orientations around the threefold axis [26][27][28][29][30][31][32][33][34][35][36][37][38]. Many compounds of this family undergo an improper ferroelastic phase transition from the high-temperature rhombohedral phase to the low-temperature monoclinic phase [8,9,16,28,[30][31][32][33][34][35][36][37][38][39]. Depending on the structure of the high-temperature phase, ABF 6 •6H 2 O crystals may be divided into two groups.…”

Section: In These Compounds Complex A[h 2 O] 2+mentioning

confidence: 99%

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Incommensurate phases in the improper ferroelastic MgGeF₆ 6H₂O:Mn²studied by means of EPR

Skrylnik

Зиатдинов²

2002

J. Phys.: Condens. Matter

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The results of an EPR study of the inhomogeneous phases existing in the temperature interval TC = 311.0 ± 0.3 K < T < Ti1 = 403 ± 0.3 K in improper ferroelastic crystals of MgGeF6 · 6H2O:Mn2+ are presented. On the basis of the analysis of the temperature and angle dependences of the experimental parameters and numerical calculations, the conclusion has been drawn that at Ti1 the crystals considered undergo a transition to a structurally modulated phase and the order parameter of this transition may be the angle of the Mg[H2O]62+ octahedra rotation around the crystal C3-axis. From Ti1 to TC the modes of the modulated phase follow according to a completely classical scenario for incommensurate crystals: the origin of the incommensurate structure with plane-wave modulation at Ti1, the appearance of structural phase solitons below Ti2 = 380 ± 0.3 K and decrease of the soliton density to values of ≈ 0.85 as the temperature decreases to T ≈ 360 K. Below that temperature the soliton density is almost unchanged down to TC and, to successfully describe the experimental spectra, the effect of variation of the spin–lattice relaxation rate over the spectrum has also been taken into account within the temperature interval considered. At TC the crystals investigated undergo a first-order improper ferroelastic phase transition into a monoclinic phase with unit-cell doubling. A comparison with results on MgSiF6 · 6H2O from a previous investigation and a theoretical analysis of the structure evolution in these crystals are also presented.

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Section: In These Compounds Complex A[h 2 O] 2+mentioning

confidence: 74%

Section: In These Compounds Complex A[h 2 O] 2+mentioning

confidence: 99%

Incommensurate phases in the improper ferroelastic MgGeF₆ 6H₂O:Mn²studied by means of EPR

Skrylnik

Зиатдинов²

2002

J. Phys.: Condens. Matter

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“…Studies on crystalline salts have established the existence of the [Mn(OH 2 ) 6 ] 2+ species in the solid state for Mn(ClO 4 ) 2 •6H 2 O, 6 Mn(NO 3 ) 2 •6H 2 O (structure type of Zn(NO 3 ) 2 •6H 2 O 7 ), Mn(OH 2 ) 6 SiF 6 , 8,9 MnSO 4 •7H 2 O (epsomite structure type 10 ) and M(I)[Mn(OH 2 ) 6 ](SO 4 ) 2 (sulfates) or M(I)-[Mn(OH 2 ) 6 ](SeO 4 ) 2 (selenates) which are of the family of Tutton's salt with M(I) = NH 4 + , K + , Rb + , and Cs + . [11][12][13] In aqueous solutions, the existence of the [Mn(OH 2 ) 6 ] 2+ has been experimentally verified by X-ray diffraction (XRD) and extended X-ray absorption spectroscopy (EXAFS).…”

Section: Introductionmentioning

confidence: 99%

Hydration and speciation studies of Mn2+ in aqueous solution with simple monovalent anions (ClO4−, NO3−, Cl−, Br−)

Rudolph

Irmer

2013

Dalton Trans.

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Raman spectroscopic measurements have been performed on aqueous solutions of Mn(ClO4)2, MnCl2, MnBr2, and Mn(NO3)2 in the terahertz region (40-600 cm(-1)) and to wavenumbers up to 4200 cm(-1) employing an absorption gap in these light pink coloured solutions. In Mn(ClO4)2 solutions of water and heavy water, the hexahydrate and its deuterate, [Mn(OH2)6](2+) and [Mn(OD2)6](2+), were characterized as showing a very weak, strongly polarized band at 354 cm(-1) and 338 cm(-1), respectively. These modes were assigned to ν1 MnO6 of [Mn(OH2)6](2+) and [Mn(OD2)6](2+). In Mn(NO3)2(aq), the undisturbed mode at 354 cm(-1), representative of manganese hexahydrate, was also detected in dilute solutions up to ~3 mol L(-1) and no sign of nitrato complex formation could be obtained. In fairly dilute MnCl2(aq) up to ~1.5 mol L(-1) the hexaaqua ions were identified but in concentrated solutions, chloro-complexes of Mn(2+) were detected in the form of [Mn(OH2)(6-n)Cl(n)]((+2-n)) with n equal to one or two. In MnBr2(aq) a comparable picture to the one in MnCl2(aq) could be obtained. Density functional theory (DFT) calculations on Mn(2+) water clusters were carried out to optimize the geometry and calculate the frequencies of the [Mn(OH2)6](2+) cluster. For this purpose an unrestricted B3LYP functional was used with a triple-ζ basis set 6-311+G(d,p). In order to include the hydration effects around the [Mn(OH2)6](2+), a continuum model approach was employed where the solvent is described by a structureless dielectric polarizable continuum using the Polarizable Continuum Model of Solvation (PCM). The gas phase cluster of [Mn(OH2)6](2+) led to lower MnO6 frequencies compared to the measured ones. A second, much larger cluster model, with 18 water molecules containing 6 waters in the first shell and an explicit second hydration shell, [Mn(OH2)6(OH2)12](2+), was modelled. Again, the cluster in vacuo and the cluster surrounded by a structureless polarizable continuum were considered. The larger cluster including the polarizable continuum gives the most realistic frequency value of ν1 MnO6 and the other MnO6 skeleton modes. The hydration enthalpy, ΔH(hyd(l)) at 298 K, of [Mn(OH2)6](2+)(aq) was calculated by applying a Born-Haber cycle and correcting for the heat of vaporization, ΔH(vap), of water and the solvation enthalpy, ΔH(solv), released by transferring the gas phase cluster into the solution. The theoretical hydration enthalpy is in fair agreement with the measured hydration enthalpy.

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“…The crystal structure of DITF has not yet been determined. However, based on the data on the crystal structures of

ASiF_{6} \cdot 6 D_{2} normalO

(A = Mg, Fe, Mn, Co), [27–30] it should be noted that the bond lengths in them are of the same order as those in hydrated complexes

FeSiF_{6} \cdot 6 H_{2} normalO

[5] and CoSiF

_{6} \cdot 6 H_{2} normalO

[31] …”

Section: Resultsmentioning

confidence: 99%

Dynamic processes of the water sublattice in FeTiF6·xH2O·yD2O crystal

Gerasimova

Крылов

Vtyurin

et al. 2022

J Raman Spectroscopy

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Phase transition in FeTiF 6 Á xH 2 O Á yD 2 O crystals has been studied by Raman spectroscopy. The 611 cm À1 line corresponding to mode A 1g of ½TiF 6 2À system does not exhibit anomalous behavior associated with the phase transition. The temperature studies showed that below the phase transition temperature, the equivalence of D 2 O molecules in FeTiF 6 Á xH 2 O Á yD 2 O octahedron is broken.The phase transition mechanism in the compound under study is associated with FeðxH 2 O Á yD 2 OÞ complex.

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A new example of an arrangement of antiphase domains: investigation by neutron diffraction of deuterated manganese fluosilicate

Cited by 23 publications

References 8 publications

Incommensurate phases in the improper ferroelastic MgGeF₆ 6H₂O:Mn²studied by means of EPR

Incommensurate phases in the improper ferroelastic MgGeF₆ 6H₂O:Mn²studied by means of EPR

Hydration and speciation studies of Mn2+ in aqueous solution with simple monovalent anions (ClO4−, NO3−, Cl−, Br−)

Dynamic processes of the water sublattice in FeTiF6·xH2O·yD2O crystal

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A new example of an arrangement of antiphase domains: investigation by neutron diffraction of deuterated manganese fluosilicate

Cited by 23 publications

References 8 publications

Incommensurate phases in the improper ferroelastic MgGeF6 6H2O:Mn2 studied by means of EPR

Incommensurate phases in the improper ferroelastic MgGeF6 6H2O:Mn2 studied by means of EPR

Hydration and speciation studies of Mn2+ in aqueous solution with simple monovalent anions (ClO4−, NO3−, Cl−, Br−)

Dynamic processes of the water sublattice in FeTiF6·xH2O·yD2O crystal

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Incommensurate phases in the improper ferroelastic MgGeF₆ 6H₂O:Mn²studied by means of EPR

Incommensurate phases in the improper ferroelastic MgGeF₆ 6H₂O:Mn²studied by means of EPR