|
|||||
|
|
Synthesis and crystal structure of MgB12 |
|
| Authors: | Volker Adasch Thilo Ludwig Natascha Vojteer Harald Hillebrecht |
| Affiliation: | a DRONCO AG, Wiesenmühle 1, D-95632 Wunsiedel, Germany b Ludwig-Maximilians-Universität München, Institut für Mineralogie, Petrologie und Geochemie, Theresienstr. 41/III, D-80333 München, Germany c Albert-Ludwigs-Universität Freiburg, Institut für Anorganische und Analytische Chemie, Albertstr. 21, D-79104 Freiburg, Germany d Freiburger Materialforschungszentrum FMF, Stefan-Maier-Str. 25, D-79104 Freiburg, Germany |
| Abstract: | Single crystals of MgB12 were synthesized from the elements in a Mg/Cu melt at 1600 °C. MgB12 crystallizes orthorhombic in space group Pnma with  ,  and  . The crystal structure (Z=30, 5796 reflections, 510 variables, R1(F)=0.049, wR2(I)=0.134) consists of a three dimensional net of B12 icosahedra and B21 units in a ratio 2:1. The B21 units are observed for the first time in a solid compound. Mg is on positions with partial occupation. The summation reveals the composition MgB12.35 or Mg0.97B12 , respectively. This is in good agreement with the value of MgB11.25 as expected by electronic reasons to stabilize the boron polyhedra  and  . |
| Keywords: | Synthesis Single crystals Structure analysis Magnesium boride Boron rich boride B21 unit WDX measurements |
| 本文献已被 ScienceDirect 等数据库收录！ | |