Synthesis, crystal growth and structure of Mg containing {beta}-rhombohedral boron: MgB{sub 17.4}

Journal Article · Fri Sep 15 00:00:00 EDT 2006 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2006.03.009· OSTI ID:20905456

Adasch, Volker ^[1]; Hess, Kai-Uwe ^[2]; Ludwig, Thilo ^[3]; Vojteer, Natascha ^[3]; Hillebrecht, Harald ^[4]

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1. DRONCO AG, Wiesenmuehle 1, D-95632 Wunsiedel (Germany)
2. Ludwig-Maximilians-Universitaet Muenchen, Institut fuer Mineralogie, Petrologie und Geochemie, Theresienstr. 41/III, D-80333 Muenchen (Germany)
3. Albert-Ludwigs-Universitaet Freiburg, Institut fuer Anorganische und Analytische Chemie, Albertstr. 21, D-79104 Freiburg (Germany)
4. Albert-Ludwigs-Universitaet Freiburg, Institut fuer Anorganische und Analytische Chemie, Albertstr. 21, D-79104 Freiburg (Germany) and Freiburger Materialforschungszentrum FMF, Stefan-Maier-Str. 25, D-79104 Freiburg (Germany)

For the first time, single crystals of Mg containing {beta}-rhombohedral boron MgB{sub 17.4} were synthesised from the elements in a Mg/Cu melt at 1600deg. C. The crystal structure determined by the refinement of single crystal data (space group R-3m, a=10.991(2)A, c=24.161(4)A, 890 reflections, 123 variables, R{sub 1}(F)=0.049, wR{sub 2}(I)=0.122) improves and modifies the former structure model derived from earlier investigations on powder samples. Mg is located on four different positions with partial occupation. While the occupation of the sites D (53.3%), E (91%) and F (7.2%) is already known from other boron-rich borides related to {beta}-rhombohedral boron, the occupation of the fourth position (18h, 6.7%) is observed for the first time. Two boron positions show partial occupation. The summation reveals the composition MgB{sub 17.4} and Mg{sub 5.85}B{sub 101.9}, respectively, confirmed by WDX measurements. The single crystals of MgB{sub 17.4} show the highest Mg content ever found. Preliminary measurements indicate no superconductivity.

• OSTI ID: 20905456
• Journal Information: Journal of Solid State Chemistry, Vol. 179, Issue 9; Conference: 15. international symposium on boron, borides and related compounds, Hamburg (Germany), 21-26 Aug 2005; Other Information: DOI: 10.1016/j.jssc.2006.03.009; PII: S0022-4596(06)00155-1; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL GROWTH
MAGNESIUM BORIDES
MONOCRYSTALS
SPACE GROUPS
SYNTHESIS
TRIGONAL LATTICES