Sc0.43(2)Rb2Mo15S19, a partially Sc-filled variant of Rb2Mo15S19

International audienceThe structure of scandium dirubidium pentadecamolybdenum nonadecasulfide, Sc0.43 (2)Rb2Mo15S19, constitutes a partially Sc-filled variant of Rb2Mo15S19 [Picard, Saillard, Gougeon, Noel & Potel (2000), J. Solid State Chem.155, 417426]. In the two compounds, which both crystallize in the Rc space group, the structural motif is characterized by a mixture of Mo6Si8Sa6 and Mo9Si11Sa6 cluster units ('i' is inner and 'a' is apical) in a 1:1 ratio. The two components are interconnected through interunit MoS bonds. The cluster units are centred at Wyckoff positions 6b and 6a (point-group symmetries and 32, respectively). The Rb+ cations occupy large voids between the different cluster units. The Rb and the two inner S atoms lie on sites with 3. symmetry (Wyckoff site 12c), and the Mo and S atoms of the median plane of the Mo9S11S6 cluster unit lie on sites with .2 symmetry (Wyckoff site 18e). A unique feature of the structure is a partially filled octahedral Sc site with symmetry. Extended Huckel tight-binding calculations provide an understanding of the variation in the MoMo distances within the Mo clusters induced by the increase in the cationic charge transfer due to the insertion of Sc

Synthesis, crystal structure and magnetic properties of Li2InMo3O8: A novel reduced molybdenum oxide containing magnetic Mo3 clusters

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Full in silico DFT characterization of lanthanum and yttrium based oxynitride semiconductors for solar fuels

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Synthesis, Crystal and Electronic Structures, and Electrical Properties of the Fifth Member of the Rb 2 (Mo 9 S 11 )(Mo 6 n S 6 n +2 ) Series: Rb 10 Mo 39 S 43 , an Atypical Reduced Molybdenum Sulfide Containing Mo 9 and Mo 30 Clusters

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Computational methodology for full in silico design of new semiconductors for water splitting: A DFT study of YTaON2 and YTiO2N

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Enhancement of the Thermoelectric Properties of FeGa3-type Structures with Group 6 Transition Metals: A Computational Exploration

International audienceThe possible existence of group 6 TM3 compounds with T = Cr, Mo, W and M = Ga, In is investigated with the aid of density functional theory calculations. Their most probable crystal structure is expected to be of the FeGa3 type tetragonal space group P42/mnm. All compounds are computed to be semiconductors with a band gap ranging from 0.08 to 0.43 eV, at the modified Becke-Johnson level of theory. The thermoelectric properties are analyzed via calculations based on Boltzmann transport equation under a constant relaxation time approximation. Promising power factors are computed for both n- and p-type WGa3 because of a band degeneracy around the Fermi level similar to that of heavily doped PbTe and SnTe materials. If the optimal chemical potential can be reached, a thermoelectric figure of merit up to 0.6 at 800 K for both n- and p-type may be expected for WGa3

Synthesis, crystal and electronic structures and magnetic properties of Li2SnMo3O8: A novel reduced molybdenum oxide containing Mo3O13 cluster units

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Prediction of high thermoelectric potential in AMN2 layered nitrides: electronic structure, phonons, and anharmonic effects

International audienceBand structures, electronic transport coefficients, harmonic and anharmonic vibrational properties of novel layered nitrides have been studied to evaluate the potential for thermoelectric applications. Using first principles theoretical methods we predict that AMN2 compounds with A = Ca, Sr, and Ba, and M = Ti, Zr, Hf may exhibit Seebeck coefficients in excess of 150 μV K−1 and good electrical conductivities. The phonon dispersions indicate the presence of low lying optic modes that can lead to low thermal conductivity. The analysis of the mode resolved Grüneisen parameter points to large anharmonicity. In addition, we show that the A-site substitution controls the degeneracies at the top of the valence band and the anisotropy of the Seebeck tensor