Chemistry:Aluminium dodecaboride

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Aluminium dodecaboride
Names
IUPAC name
Aluminium dodecaboride
Other names
AlB12
Identifiers
3D model (JSmol)
EC Number
  • 234-924-2
Properties
AlB
12
Molar mass 156.714 g/mol[1]
Appearance Yellow to black solid[1]
Density 2.55 g/cm3[1]
Melting point 2,070 °C (3,760 °F; 2,340 K)[1]
insoluble
Solubility soluble in hot nitric acid (decomposes),[2]
soluble in nitric acid (decomposes),[3]
soluble in sulfuric acid (decomposes)[3]
Structure
Tetragonal (α-form)
Orthorhombic (β-form)
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

Aluminium dodecaboride (AlB
12
) is a superhard chemical compound with 17% aluminium content by weight.

It is the hardest boride of the aluminium-boron system, which also includes AlB
10
, AlB
4
, AlB
2
and AlB.

Properties

There are two crystalline forms, α-AlB
12
, and γ-AlB
12
. Both forms are very similar and consist of a framework with three-dimensional networks of B
12
and B
20
units.[4] The phase β-AlB
12
is now believed to be the ternary boride C
2
Al
3
B
48
.[5]

Preparation

The β-form can be prepared by the reaction of boron(III) oxide with sulfur and aluminium, then adding carbon to the mixture.

Uses

The extreme hardness of AlB
12
makes it a favorable component of PCBN inserts, which are mainly used in cutting and grinding to replace diamond or corundum.

See also

Footnotes

  1. 1.0 1.1 1.2 1.3 Haynes, William M., ed (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.45. ISBN 1439855110. 
  2. Martienssen, Werner; Warlimont, Hans (2005). Springer Handbook of Condensed Matter and Materials Data. Springer-Verlag. pp. 1025. ISBN 9783540443766. Bibcode2005shcm.book.....M. 
  3. 3.0 3.1 Rebekoff Reeve, Martin (1991) Method of producing an aluminium boride. EP 0130016 B1
  4. Higashi, Iwami (2000). "Crystal chemistry of α-AlB12 and γ-AlB12". Journal of Solid State Chemistry 154 (1): 168–176. doi:10.1006/jssc.2000.8831. Bibcode2000JSSCh.154..168H. 
  5. Matkovich, V. I; Giese, R. F; Economy, J (1965). "Phases and twinning in C2Al3B48 (β-AlB12)". Zeitschrift für Kristallographie 122 (1–2): 108. doi:10.1524/zkri.1965.122.1-2.108. Bibcode1965ZK....122..108M. 

External links