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Behrens, Peter; Assmann, Stefanie; Bilow, Uta; Linke, Christoph; Jansen, Martin

doi:10.1002/(sici)1521-3749(199901)625:1<111::aid-zaac111>3.3.co;2-z

Cited by 20 publications

(35 citation statements)

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“…The corresponding feature is less prominent in the O K-edge spectrum of O ␣ [40]. The intensity of the O K-edge signal increases with metal-oxygen bond covalency [62,63], since covalent bonding reduces the number of filled states with O 2p character. This indicates that the degree of silver-oxygen bond covalence, and hence O2p Ag4d hybridisation, is higher for the O ␥ species.…”

Section: Basis For the Differing Reactivity Of The O ␣ And O ␥ Speciesmentioning

confidence: 99%

Mechanism and active sites for the partial oxidation of methanol to formaldehyde over an electrolytic silver catalyst

Waterhouse

Bowmaker

Metson

2004

Applied Catalysis A: General

117

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Section: Basis For the Differing Reactivity Of The O ␣ And O ␥ Speciesmentioning

confidence: 99%

Mechanism and active sites for the partial oxidation of methanol to formaldehyde over an electrolytic silver catalyst

Waterhouse

Bowmaker

Metson

2004

Applied Catalysis A: General

117

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“…compounds that contain the element with the same valence state and the same or very similar local structure to the element on each site in the sample. 43,63,64 We applied this procedure to the Ag XANES spectrum measured for the Ag 3 (SbF 6 ) 4 sample. The spectrum may indeed be described as a linear combination of the XANES profiles of AgSbF 6 (containing Ag(I) in the 8-coordinated site) and IF 6 [Ag(SbF 6 ) 3 ] (containing Ag(II) in a closeto square-planar site) (Fig.…”

Section: ) 3 ] Referencesmentioning

confidence: 99%

The first example of a mixed valence ternary compound of silver with random distribution of Ag(i) and Ag(ii) cations

et al. 2015

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The reaction between colourless AgSbF6 and sky-blue Ag(SbF6)2 (molar ratio 2 : 1) in gaseous HF at 323 K yields green Ag3(SbF6)4, a new mixed-valence ternary fluoride of silver. Unlike in all other Ag(I)/Ag(II) systems known to date, the Ag(+) and Ag(2+) cations are randomly distributed on a single 12b Wyckoff position at the 4̄ axis of the I4̄3d cell. Each silver forms four short (4 × 2.316(7) Å) and four long (4 × 2.764(6) Å) contacts with the neighbouring fluorine atoms. The valence bond sum analysis suggests that such coordination would correspond to a severely overbonded Ag(I) and strongly underbonded Ag(II). Thorough inspection of thermal ellipsoids of the fluorine atoms closest to Ag centres reveals their unusual shape, indicating that silver atoms must in fact have different local coordination spheres; this is not immediately apparent from the crystal structure due to static disorder of fluorine atoms. The Ag K-edge XANES analysis confirmed that the average oxidation state of silver is indeed close to +1⅓. The optical absorption spectra lack features typical of a metal thus pointing out to the semiconducting nature of Ag3(SbF6)4. Ag3(SbF6)4 is magnetically diluted and paramagnetic (μ(eff) = 1.9 μ(B)) down to 20 K with a very weak temperature independent paramagnetism. Below 20 K weak antiferromagnetism is observed (Θ = -4.1 K). Replacement of Ag(I) with potassium gives K(I)2Ag(II)(SbF6)4 which is isostructural to Ag(I)2Ag(II)(SbF6)4. Ag3(SbF6)4 is a genuine mixed-valence Ag(I)/Ag(II) compound, i.e. Robin and Day Class I system (localized valences), despite Ag(I) and Ag(II) adopting the same crystallographic position.

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“…An x-ray absorption near-edge structure ͑XANES͒ study has also supported the Ag I / Ag III theory. 18 The authors considered both Ag L 1 and L 3 XANES spectra for a range of binary oxides and silver containing compounds with the trends in the data clearly supporting an Ag I and Ag III mixed oxidation state rather than Ag I and Ag II .…”

Section: Introductionmentioning

confidence: 97%

Electronic structure of mixed-valence silver oxide AgO from hybrid density-functional theory

2010

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Mixed-valence AgO has attracted attention due to its utility in battery technologies. Despite this, a nanoscopic understanding of its electronic structure has been lacking and there has been considerable controversy about the formal oxidation states of silver in the system. In this Rapid Communication we study the electronic structure of AgO using density functional theory:generalized gradient approximation ͑GGA͒ and a screened hybrid density functional ͑HSE͒. GGA is found to be unable to model the mixed valence of the material, resulting in an Ag II O symmetric structure. We show conclusively using HSE that the oxidation states of silver in AgO are Ag I and Ag III , and not Ag I and Ag II with holes on neighboring oxygen ions as had previously been predicted.

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Cited by 20 publications

References 0 publications

Mechanism and active sites for the partial oxidation of methanol to formaldehyde over an electrolytic silver catalyst

Mechanism and active sites for the partial oxidation of methanol to formaldehyde over an electrolytic silver catalyst

The first example of a mixed valence ternary compound of silver with random distribution of Ag(i) and Ag(ii) cations

Electronic structure of mixed-valence silver oxide AgO from hybrid density-functional theory

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