Synthesis,Crystal Structure,Bonding, and Properties of (Ba6O)(OsN3)2 |
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Authors: | Carsten L. Schmidt Ulrich Wedig Dr. Robert Dinnebier Prof. Dr. Martin Jansen Prof. Dr. |
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Affiliation: | Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart (Germany), Fax: (+49)?711?689?1502 |
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Abstract: | The new barium nitridoosmate oxide (Ba6O)(OsN3)2 was prepared by reacting elemental barium and osmium (3:1) in nitrogen at 815–830 °C. The crystal structure of (Ba6O)(OsN3)2 as determined by laboratory powder X‐ray diffraction ( , No 148: a=b=8.112(1) Å, c=17.390(1) Å, V=991.0(1) Å3, Z=3), consists of sheets of trigonal OsN3 units and trigonal‐antiprismatic Ba6O groups, and is structurally related to the “313 nitrides” AE3MN3 (AE=Ca, Sr, Ba, M=V–Co, Ga). Density functional calculations, using a hybrid functional, likewise indicate the existence of oxygen in the Ba6 polyhedra. The oxidation state 4+ of osmium is confirmed, both by the calculations and by XPS measurements. The bonding properties of the OsN35? units are analyzed and compared to the Raman spectrum. The compound is paramagnetic from room temperature down to T=10 K. Between room temperature and 100 K it obeys the Curie–Weiss law (μ=1.68 μB). (Ba6O)(OsN3)2 is semiconducting with a good electronic conductivity at room temperature (8.74×10?2 Ω?1 cm?1). Below 142 K the temperature dependence of the conductivity resembles that of a variable‐range hopping mechanism. |
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Keywords: | density functional calculations nitrides osmium semiconductors X‐ray diffraction |
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