Thermal Decomposition of Prussian Blue Analogues of the Type Fe[Fe(CN)<sub>5</sub>NO]

Inoue, Hidenari; Narino, Shuichi; Yoshioka, Naoki; Fluck, E.

doi:10.1515/znb-2000-0803

Cited by 13 publications

(8 citation statements)

References 9 publications

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“…The zeolitic and coordinated water amounts to ideally 4 water molecules per formula unit and ca. 26 wt %, (ii) above 180 °Ca gradual decomposition of the compound. , The exchange of water molecules between the sample and the surrounding environment is very fast already at room temperature. This is illustrated for Cu II [Fe III (CN) 6 ] 2/3 · n H 2 O, (i) in Figure a, where a significant weight loss is observed already at the 2 h dwell time and starting temperature of 30 °C and (ii) in Figure b, in which the sample was twice heated to 120 °C at 10 °C/min and equilibrated at room temperature and ambient atmosphere for 2 h in between.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

confidence: 99%

Structure Characterization and Properties of K-Containing Copper Hexacyanoferrate

et al. 2016

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“…However, because of the random distribution of the vacant sites, the amount of coordinated water molecules is slightly higher, ∼1.1, as suggested by the water adsorption isotherms (Balmaseda et al , 2003). Once the complexes have been dehydrated they remain stable, preserving the crystal structure, up to about 175 °C where the decomposition process begins with the loss of the NO ligand and then, at higher temperature, also releasing CN ligands(Inoue et al , 2000).…”

Section: Resultsmentioning

confidence: 99%

Crystal structures of cubic nitroprussides: M[Fe(CN)₅NO]·xH₂O(M=Fe, Co, Ni). Obtaining structural information from the background

Gómez

Rodríguez‐Hernández

Reguera³

2007

Powder Diffr.

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A new structural model is proposed for cubic nitroprussides and the crystal structure for the complex salts of Fe(2+), Co(2+), and Ni(2+) refined in that model. In cubic nitroprussides the building unit, [Fe(CN)5NO]2−, and the assembling metal (M=Fe2+, Co2+, Ni2+), have ¾ occupancy with three formula units per cell (Z=3). This leads to certain structural disorder and to different local environments for the outer metal. The crystallographic results are supported by the Mössbauer and infrared data. The XRD powder patterns, index in a cubic cell (Fm3m space group), show a sinuous background because of diffuse scattering from positional disorder of the metal centers. Because of this, the crystal structures were refined allowing the metal centers to move from the (0,0,0) and (0,0,1/2) positions (away from positional symmetry restrictions). The refinement under these conditions leads to excellent agreement factors (Rwp, Rp, S), good pattern background fitting, and produced a refined structural model consistent with the crystal chemistry of nitroprussides. The studied materials are obtained as hydrates. On heating, the crystal water evolves, and below 100°C an anhydrous phase is obtained, preserving the framework of the original hydrates. The loss of the crystal water leads to cell contraction that represents around 2% of cell volume reduction. On cooling down from room temperature to 77 and 12 K, a slight expansion for the -M-N≡C-Fe-C≡N-M- chain length is observed, suggesting that at low temperature and reduction in the metals charge delocalization on the CN bridges takes place. For M=Fe and Co the crystal structure was also refined for the anhydrous phase at 12, 77, and 300 K.

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“…In Fig. 5, one observes that the 150°C spectra of both materials exhibit the strong C"N stretching band at $2085 cm À1 , which is characteristic of the Fe 2+ -CN-Fe 3+ group [27,32,33]. In the 320°C spectrum of AFFC, the C"N peak has split into a doublet with wavenumbers $2027 and 2072 cm À1 , indicating the presence of [Fe 2+ (CN) 6 ] 4À anions [33] formed on decomposition of the FFC structure.…”

Section: Ftir Spectroscopymentioning

confidence: 92%

“…2, inset). A further decrease is observed at temperatures above 240°C and the gallery height finally reduces to $0.1 nm at about 320°C, indicating that at these temperatures the intercalated structure has essentially broken down, leaving in the interlayer residues like, e.g., Fe(CN) 2 [26][27][28]. This trend is in qualitative agreement with XRD results by Miyata and Hirose [29] showing that the interlayer gallery of a Mg-Al-[Fe(CN) 6 ] 4À hydrotalcite has drastically decreased at 250°C.…”

Section: Synthesis and Clay Intercalation Of The Cationic Pb Compoundmentioning

confidence: 99%

“…Of particular significance is the dissimilarity of the AFFC and ST-Al-FFC traces in the 300-500°C region, since it indicates that the thermal decomposition of the ferric ferrocyanide structure in these two materials goes through different rearrangement and recrystallization modes. More specifically, the processes known to unfold during the thermal decomposition of ferric ferrocyanides [26][27][28] suggest that the aforementioned differences are probably caused by the presence of Al-hydroxy cations in ST-Al-FFC (see below). In a simplified way, these processes can be depicted as follows: the onset of CN liberation around 300°C leads to reduction of trivalent iron and subsequent disruption of the Fe 2+ -CN-Fe 3+ network.…”

Section: Hrtem Imagesmentioning

confidence: 99%

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A two-dimensional magnetic hybrid material based on intercalation of a cationic Prussian blue analog in montmorillonite nanoclay

Gournis

Papachristodoulou

Maccallini

et al. 2010

Journal of Colloid and Interface Science

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A highly ordered two-dimensional hybrid magnetic nanocomposite has been prepared by synthesizing and intercalating a new cationic aluminum-hydroxy ferric ferrocyanide compound into a cation-adsorbing nanoclay (montmorillonite). Chemical and structural properties were investigated by X-ray diffraction, transmission electron microscopy, thermogravimetric and differential thermal analyses, Fourier transform infrared, X-ray photoemission, and Mössbauer spectroscopies. Elemental analysis was based on proton-induced gamma ray emission and X-ray fluorescence spectroscopy data, N/C elemental ratios, and cation-exchange capacity measurements. Magnetic properties were studied by SQUID magnetometry. The results suggest: (i) that the cationic Prussian blue analog comprises Al-hydroxy cations embedded into a monolayer thick two-dimensional ferric ferrocyanide array; and (ii) that the clay-Prussian blue nanohybrid consists of such arrays stacked between the clay layers. The latter material orders ferromagnetically at approximately 5K showing a hundred times higher remanence than that of the starting material, soluble Prussian blue (ammonium ferric ferrocyanide).

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Thermal Decomposition of Prussian Blue Analogues of the Type Fe[Fe(CN)₅NO]

Cited by 13 publications

References 9 publications

Structure Characterization and Properties of K-Containing Copper Hexacyanoferrate

Structure Characterization and Properties of K-Containing Copper Hexacyanoferrate

Crystal structures of cubic nitroprussides: M[Fe(CN)₅NO]·xH₂O(M=Fe, Co, Ni). Obtaining structural information from the background

A two-dimensional magnetic hybrid material based on intercalation of a cationic Prussian blue analog in montmorillonite nanoclay

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Thermal Decomposition of Prussian Blue Analogues of the Type Fe[Fe(CN)5NO]

Cited by 13 publications

References 9 publications

Structure Characterization and Properties of K-Containing Copper Hexacyanoferrate

Structure Characterization and Properties of K-Containing Copper Hexacyanoferrate

Crystal structures of cubic nitroprussides: M[Fe(CN)5NO]·xH2O(M=Fe, Co, Ni). Obtaining structural information from the background

A two-dimensional magnetic hybrid material based on intercalation of a cationic Prussian blue analog in montmorillonite nanoclay

Contact Info

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Resources

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Thermal Decomposition of Prussian Blue Analogues of the Type Fe[Fe(CN)₅NO]

Crystal structures of cubic nitroprussides: M[Fe(CN)₅NO]·xH₂O(M=Fe, Co, Ni). Obtaining structural information from the background