Transformation of cadmium ferricyanide by heating, milling and sonication

Reguera, E.; Balmaseda, J.; Quintana, Geraldine Ezquerra; Gómez, Ariel; Fernández‐Bertrán, J.

doi:10.1016/s0277-5387(97)00518-4

Cited by 24 publications

(9 citation statements)

References 46 publications

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“…When milled or heated ferricyanides reduce

Figure 2.Mössbauer spectra at room temperature of: (a) Cd 2 [Fe(CN) 6 ]⋅8H 2 O, (b) Cd 2 [Fe(CN) 6 ], (c) CdCs 2 [Fe(CN) 6 ], (d) CdK 2 [Fe(CN) 6 ]⋅2H 2 O, (e) Cd 3 [Fe(CN) 6 ] 2 ⋅10H 2 O. A similar set of spectra are obtained for manganous hexacyanoferrates (II,III). to form ferrocyanides which remain stable up to relatively high temperatures [Reguera et al , 1998].…”

Section: Resultsmentioning

confidence: 82%

Crystal structures of some manganese(II) and cadmium hexacyanoferrates (II,III) and structural transformations related to the sorption of Cesium

et al. 2004

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Mn2+and Cd2+form a family of isostructural hexacyanoferrates(II,III). Their crystal structures, including those of mixed compositions containing K+and Cs+as charge balance cations, were resolved and refined from XRD powder patterns. The crystal structures of M3[Fe(CN)6]2⋅xH2O and MCs2[Fe(CN)6] (where M=Mn, Cd) were refined in the space group Fm3m. The mixed salts, MK2[Fe(CN)6]⋅2H2O, were found to be orthorhombic (space group Pmn21). The orthorhombic structure results from a local distortion due to monohydrated potassium ions located in interstitial sites. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+is a large ion, which practically fills the available interstitial voids stabilizing the cubic structure. In solutions of K+and Cs+the single salts, M2[Fe(CN)6]⋅8H2O (monoclinic P21/n) also transform, in this case liberating M2+ions and forming the corresponding mixed salts. An analogous but slow structural transformation was also observed in the anhydrous forms of these single salts. These structural transformations could be relevant to the use of these compounds as ion exchangers and particularly for the sorption of137Cs+from radioactive waste solutions. The XRD data were complemented with structural information from infrared (IR), Mössbauer and water vapor adsorption techniques. ©2004 International Centre for Diffraction Data.

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“…When milled or heated ferricyanides reduce

Section: Resultsmentioning

confidence: 82%

Crystal structures of some manganese(II) and cadmium hexacyanoferrates (II,III) and structural transformations related to the sorption of Cesium

et al. 2004

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“…The v (CN) band position in hexacyanoferrates allows unequivocal differentiation between ferrocyanides and ferricyanides. ,− The v (CN) band positions in Fe III –CN–Cu II and Fe II –CN–Cu II links are very close to 2178 and 2093 cm –1 , respectively. Their intensities can thus be used to estimate Fe III and Fe II contents in the samples.…”

Section: Resultsmentioning

confidence: 97%

“…Voids or cavities in the framework constitute locations for water molecules and/or alkali ions. While only the Fm 3̅ m structure model is relevant here, note that a number of PBAs exhibit structures with different connections of octahedra and lower space group symmetries. − It should also be remembered that most PB/PBA structures are inherently disordered and that local ordering of structural motifs are to be expected. ,, …”

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confidence: 99%

Structure Characterization and Properties of K-Containing Copper Hexacyanoferrate

et al. 2016

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Copper hexacyanoferrate, Cu(II)[Fe(III)(CN)6]2/3·nH2O, was synthesized, and varied amounts of K(+) ions were inserted via reduction by K2S2O3 (aq). Ideally, the reaction can be written as Cu(II)[Fe(III)(CN)6]2/3·nH2O + 2x/3K(+) + 2x/3e(-) ↔ K2x/3Cu(II)[Fe(II)xFe(III)1-x(CN)6]2/3·nH2O. Infrared, Raman, and Mössbauer spectroscopy studies show that Fe(III) is continuously reduced to Fe(II) with increasing x, accompanied by a decrease of the a-axis of the cubic Fm3̅m unit cell. Elemental analysis of K by inductively coupled plasma shows that the insertion only begins when a significant fraction, ∼20% of the Fe(III), has already been reduced. Thermogravimetric analysis shows a fast exchange of water with ambient atmosphere and a total weight loss of ∼26 wt % upon heating to 180 °C, above which the structure starts to decompose. The crystal structures of Cu(II)[Fe(III)(CN)6]2/3·nH2O and K2/3Cu[Fe(CN)6]2/3·nH2O were refined using synchrotron X-ray powder diffraction data. In both, one-third of the Fe(CN)6 groups are vacant, and the octahedron around Cu(II) is completed by water molecules. In the two structures, difference Fourier maps reveal three additional zeolitic water sites (8c, 32f, and 48g) in the center of the cavities formed by the -Cu-N-C-Fe- framework. The K-containing compound shows an increased electron density at two of these sites (32f and 48g), indicating them to be the preferred positions for the K(+) ions.

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“…This strengthening in the Fe–CN bond is also related to the high stability observed for ferrocyanides. When milled or heated, ferricyanides transform into ferrocyanides which remain stable up to relatively high temperatures (Reguera et al , 1998).…”

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confidence: 99%

On the crystal structures of some nickel hexacyanoferrates (II,III)

et al. 2004

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The crystal structures of some nickel hexacyanoferrates (II, III), including mixed compositions containing Na+, K+ and Cs+, were resolved and refined from XRD powder patterns. Data from infrared, Mössbauer and adsorption techniques provided complementary structural information. The crystal structures of Ni3[Fe(CN)6]2⋅16H2O and NiCs2[Fe(CN)6] were refined in space group Fm3m. NiNa2[Fe(CN)6]⋅2H2O and NiK2[Fe(CN)6]⋅2H2O were found to be orthorhombic (space group Pmn21). This structure (Pmn21) results from a distortion around the alkali ion, which appears as a monohydrated interstitial species. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+ is a large cation and space is not available for interstitial water molecules. This orthorhombic model is also supported by the Mössbauer spectra of the ferrous analogs, FeK2[Fe(CN)6]⋅xH2O and Fe[Pt(CN)6]. © 2004 International Centre for Diffraction Data.

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Transformation of cadmium ferricyanide by heating, milling and sonication

Cited by 24 publications

References 46 publications

Crystal structures of some manganese(II) and cadmium hexacyanoferrates (II,III) and structural transformations related to the sorption of Cesium

Crystal structures of some manganese(II) and cadmium hexacyanoferrates (II,III) and structural transformations related to the sorption of Cesium

Structure Characterization and Properties of K-Containing Copper Hexacyanoferrate

On the crystal structures of some nickel hexacyanoferrates (II,III)

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