Quantification of the Interlayer Charge Transfer, via Bond Valence Calculation, in 2D Misfit Compounds: The Case of (Pb(Mn, Nb)0.5S1.5)1.15NbS2
✍ Scribed by C. Deudon; A. Lafond; O. Leynaud; Y. Moëlo; A. Meerschaut
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 308 KB
- Volume
- 155
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
The new layered mis5t sul5de of the 1.5Q/1H homologue type, (Pb(Mn, Nb) 0.5 S 1.5 ) 1.15 NbS 2 , has been synthesized. Electron probe microanalysis gives the chemical formula (Pb 1.02 Mn 0.33 Nb 0.16 S 1.50 ) 1.15 NbS 2 , indicating Nb incorporation in the rock-salt-type part (Q layer). Its crystal structure has been solved through a superspace approach: orthorhombic symmetry, superspace group Cm2m( 00), cell parameters a ؍ 3.326(1), b ؍ 5.788(1), c ؍ 14.326(3) A > , q vector (0.5744(2),0,0); R ؍ 2.27% for 688 re6ections and 36 variables. Nb-for-Mn substitution in the central part of the Q layer is clearly proved. Bond valence calculation on this compound, compared to some other mis5t compounds, makes it possible to evaluate the charge transfer that governs the stability of such composite materials. This calculation, which takes into account the modulation of Pb+S H bondings at the Q/H interface through the superspace approach, shows that the transfer depends on the nature of cations in the Q layer. This leads to a formal oxidation state for Nb, within the H layer, varying between &3 and 3.6.