| 1. |
- Akselrud, Lev, et al.
(författare)
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Order and disorder in the modulated phase hp-Mg9Ge5.1
- 2022
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Ingår i: Zeitschrift fur Anorganische und Allgemeine Chemie. - : Wiley. - 0044-2313 .- 1521-3749. ; 648:10
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Tidskriftsartikel (refereegranskat)abstract
- Single crystals of Mg9Ge5.1(2) were obtained at a pressure of 5 GPa in the temperature range 723 to 1273 K. The metastable high-pressure phase exhibits a crystal structure, which may be described as a host-guest variety of an UCl3-type framework. The atomic arrangement is characterized by a host crystal structure Mg9Ge3 with disordered germanium guests (≈2 Ge per formula unit) in the channels. The composite arrangement undergoes incommensurate modulation. Upon heating at ambient pressure, the phase transforms into the thermodynamically stable compounds Mg2Ge and Ge at 496(5) K. Measurements of the magnetic susceptibility indicate diamagnetic behavior between 75 and 350 K.
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| 2. |
- Hübner, Julia Maria, et al.
(författare)
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A Borosilicide with Clathrate VIII Structure
- 2022
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 144:30, s. 13456-13460
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Tidskriftsartikel (refereegranskat)abstract
- The high-pressure phase Na8BxSi46-x(3 < x < 5) is the first representative of a borosilicide crystallizing in the rarely occurring clathrate VIII type structure. Crystals with composition Na8B4Si42(space group I43¯ m; a = 9.7187(2) Å Pearson symbol cI54) were obtained at 5-8 GPa and 1200 K. The clathrate I modification exists for the same composition at lower pressure with a larger cell volume (Pm3¯ n; a = 9. 977(2) Å cP54). Profound structural adaptions allow for a higher density of the clathrate VIII type than clathrate I, opening up the perspective of obtaining clathrate VIII type compounds as high-pressure forms of clathrate I.
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| 3. |
- Höhn, Peter, et al.
(författare)
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Li16Sr6Ge6N, Li16Sr6Ge6.5 and related lithium alkaline-earth metal tetrelides : Alternative filling of voids by nitride or tetrelide ions
- 2022
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Ingår i: Zeitschrift für Anorganische und Allgemeines Chemie. - : Wiley. - 0044-2313 .- 1521-3749. ; 648:23
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Tidskriftsartikel (refereegranskat)abstract
- Large black single crystals with a metallic luster of Li16Sr6Ge6N and several other representatives of the series Li16Ae6Tt6N and Li16Ae6Tt6.5 (Ae=Ca, Sr; Tt=Si, Ge, Sn, Pb) were grown from mixtures of the respective elements with addition of binary alkaline-earth metal nitrides or lithium nitride in the case of the nitrides. For the synthesis a modified high-temperature centrifugation-aided filtration (HTCAF) technique using reactive lithium melts was employed. These metallic phases crystallize in an ordered defect-variant of the Sc11Ir4 type with selective occupation of the smaller octahedral voids in the origin (000) with N and the larger rhombic dodecahedral voids in (00 1/2 ) with Tt. Charge balance assuming the presence of exclusively closed shell ions for all examples accounts for an electronic excess. Diamagnetism despite metallic properties is consistent with results from electronic structure calculations.
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