- Enhancement in the thermoelectric performance by y substitution on SrSi2
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We report the results of the Y substitution in Sr1-xY xSi2 with x≤0.15 via measuring the temperature- dependent electrical resistivity, thermal conductivity, as well as Seebeck coefficient. Upon substituting Y onto the Sr
- Lue,Chou,Kaurav,Chung,Kuo
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- High-pressure synthesis of strontium hexasilicide
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The binary phase SrSi6 was prepared at a pressure of 10(1) GPa and a temperature of 1520(150) K. Single crystal refinements and powder diffraction data reveal that the compound crystallizes in the orthorhombic crystal system (Cmcm, a = 4.4692(4), b = 10.256(1), c = 11.698(1) ?) and is isopointal to EuGa2Ge4 and EuSi6. Exothermic decomposition of the compound into SrSi2 and Si at 797 K and ambient pressure indicates that the compound is a metastable high-pressure phase. Analysis of the chemical bonding using the electron localization function and calculated charge densities reveals covalent bonding within the polyanion of four-bonded silicon atoms. Strontium cations are enclosed in the 3D net resulting in an electron balance Sr2+[Si0] 62-. In the electronic density of states the excess electrons of the framework are assigned to a filling of antibonding bands. SrSi6 is a metallic conductor with an electrical resistivity of p ≈ 250 μΩ·cm at 300 K. Magnetization measurements indicate diamagnetic behaviour (χ0 = -50·10-6 emu·mol-1).
- Wosylus, Aron,Prots, Yurii,Burkhardt, Ulrich,Schnelle, Walter,Schwarz, Ulrich,Grin, Yuri
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- Reduction of solid silicon monoxide by elemental metals
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Reaction of solid SiO with calcium in various ratios at 900°C results in the formation of a mixture of CaO, CaSi and Ca5Si3. When the reaction (in a 1:3 ratio) is carried out at 750°C, CaO and Ca3SiO are formed. The structure of the latter compound, which is erroneously described in the literature as cubic Ca2Si , was determined from powder diffraction data. In the reaction mixtures of solid SiO with strontium or titanium, SrSi, SrSi2 and Ti5Si3 were identified. Reaction with aluminium did not result in the formation of a silicide, but of elemental silicon instead.
- Biehl,Schubert,Kubel
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p. 994 - 998
(2007/10/03)
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