Synthesis, crystal structure, and properties of Mg(x)B50C8 or Mg(x)(B12)4(CBC)2(C2)2 (x = 2.4-4).

Single crystals of a new magnesium boride carbide Mg(x)B(50)C(8) (x = 2.4-4) were synthesized from the elements in a metallic melt using tantalum ampules. Crystals were characterized by single crystal X-ray diffraction and electron microprobe analysis.

Synthesis, crystal structure, and properties of two modifications of MgB(12)C(2).

Single crystals of two modifications of the new magnesium boride carbide MgB(12)C(2) were synthesized from the elements in a metallic melt by using tantalum ampoules. Crystals were characterized by single-crystal X-ray diffraction and electron microprobe analysis (energy-dispersive (EDX) and wavelength-dispersive (WDX) X-ray spectroscopy). Orthorhombic MgB(12)C(2) is formed in a Cu/Mg melt at 1873 K.