Scandium dodecaboride

Scandium dodecaboride

Names
IUPAC name scandium dodecaboride
Properties
Chemical formula	ScB12
Molar mass	174.69 g/mol
Structure
Crystal structure	Tetragonal, tI26
Space group	I4/mmm, No. 139
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Scandium dodecaboride is a refractory metal boride.

Synthesis

ScB₁₂ is formed by mixing a 7:1 ratio of boron powder and scandium oxide powder, heating to 2500 °C with a plasma torch or similar, quenching in cold water and washing with concentrated hydrochloric acid.^[1]

Crystallography

ScB₁₂ was originally reported as having a cubic structure,^[2] later studies showed it to have tetragonal structure (unit cell with a=522pm, c=735pm).^[1] More recently it has been shown that there is indeed a cubic form but that it requires stabilization.^[3]

References

1. Matkovich, V.I.; J Economy; R F Giese Jr; R Barrett (1965). "The structure of metallic dodecaborides" (PDF). Acta Crystallogr. 19 (6): 1056–1058. doi:10.1107/S0365110X65004954. Retrieved 2008-08-28.
2. Przybylska, Maria; Allan H. Reddoch; George J. Ritter (1963). "The Preparation and Structure of Lutetium Diboride, Scandium Dodecaboride and Lutetium Antimonide". J. Am. Chem. Soc 85 (4): 407–411. doi:10.1021/ja00887a008.
3. Paderno, Y.; N. Shitsevalova (1995). "Stabilization of cubic scandium dodecaboride". Journal of Alloys and Compounds 219 (1–2): 119–123. doi:10.1016/0925-8388(94)05048-1.