Synthesis and crystal structure of Mg{sub 2}B{sub 24}C, a new boron-rich boride related to 'tetragonal boron I'
- DRONCO AG, Wiesenmuehle 1, D-95632 Wunsiedel (Germany)
- Ludwig-Maximilians-Universitaet Muenchen, Institut fuer Mineralogie, Petrologie und Geochemie, Theresienstr. 41/III, D-80333 Munich (Germany)
- Albert-Ludwigs-Universitaet Freiburg, Institut fuer Anorganische und Analytische Chemie, Albertstr. 21, D-79104 Freiburg (Germany)
- 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)
Single crystals of Mg{sub 2}B{sub 24}C, a new boron-rich boridecarbide of magnesium, were synthesized as black needles and columns by reaction of the elements in Ta ampoules and BN crucibles at 1300 deg. C. The crystal structure was determined by X-ray diffraction (P-4n2, a=8.9391(13)A, c=5.0745(10)A, Z=2, 713 reflections, 64 variables, R{sub 1}(F)=0.0235, wR{sub 2}(I)=0.0591). It is closely related to 'tetragonal boron I' and can be described as a tetragonal rod packing of corner-linked B{sub 12} icosahedra with C and Mg atoms in the voids. Each B{sub 12} icosahedron has 2 B-C bonds and 10 exohedral bonds to other icosahedra, 2 within the rod and 4x2 to neighbouring rods. The isolated C atoms are 4-fold coordinated forming distorted tetrahedra. Mg is placed on two crystallographically independent positions within the three-dimensional B{sub 12}C network. Mg{sub 2}B{sub 24}C is the first example for a compound related to 'tetragonal boron I' with a stoichiometric composition.
- OSTI ID:
- 20905361
- Journal Information:
- Journal of Solid State Chemistry, Vol. 179, Issue 7; Other Information: DOI: 10.1016/j.jssc.2006.04.021; PII: S0022-4596(06)00227-1; 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
Similar Records
Synthesis, crystal structure and properties of Mg{sub 3}B{sub 36}Si{sub 9}C and related rare earth compounds RE{sub 3−x}B{sub 36}Si{sub 9}C (RE=Y, Gd–Lu)
THE STRUCTURE OF TETRAGONAL BORON