Aluminium diboride

Aluminium diboride
Names
IUPAC name
aluminium diboride
Other names
aluminium boride
Identifiers
CAS Number
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.736
EC Number
  • 234-923-7
PubChem CID
CompTox Dashboard (EPA)
InChI
  • InChI=1S/Al.B2/c;1-2/q-2;+2 checkY
    Key: XGNZNBRDPPLKTC-UHFFFAOYSA-N checkY
  • InChI=1/Al.B2/c;1-2/q-2;+2/rAlB2/c1-2-3-1
    Key: XGNZNBRDPPLKTC-DOGMWQOPAK
SMILES
  • B1=B[Al]1
Properties
Chemical formula
AlB2
Molar mass 48.604 g/mol[1]
Appearance Copper-red solid
Density 3.19 g/cm3[1]
Melting point >920 °C (decomposes)[1]
Solubility in water
insoluble
Structure[2]
Crystal structure
Hexagonal, hP3
Space group
P6/mmm, No. 191
Lattice constant
a = 0.3009 nm, b = 0.3009 nm, c = 0.3262 nm,
α = 90°, β = 90°, γ = 120°
Formula units (Z)
1
Thermochemistry
Heat capacity (C)
43.6 J/mol K
Std molar
entropy (S298)
34.7 J/mol K
Std enthalpy of
formation fH298)
−151 kJ/mol
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 diboride (AlB2) is a chemical compound made from the metal aluminium and the metalloid boron. It is one of two compounds of aluminium and boron, the other being AlB12, which are both commonly referred to as aluminium boride.

Structurally the B atoms form graphite-like sheets with Al atoms between them, and this is very similar to the structure of magnesium diboride. Single crystals of AlB2 exhibit metallic conductivity along the axis parallel to the basal hexagonal plane.[3]

Aluminium boride is considered a hazardous substance as it reacts with acids and hydrogen gas to produce toxic gases. For example, it reacts with hydrochloric acid to release borane and aluminium chloride.

The crystal structure of AlB2 is often used as a prototype structure to describe intermetallic compounds. There are a large number of structure types that fall within the AlB2 structural family.[4]

See also

  • Boride

References

  1. ^ a b c Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, Florida: CRC Press. p. 4.45. ISBN 1-4398-5511-0.
  2. ^ Felten, Edward J (1956). "The Preparation of Aluminium Diboride, AlB21". Journal of the American Chemical Society. 78 (23): 5977–5978. doi:10.1021/ja01604a003.
  3. ^ Burkhardt, U; Gurin, Vladimir; Haarmann, Frank; Borrmann, Horst; Schnelle, Walter; Yaresko, Alexander; Grin, Yuri (2004). "On the electronic and structural properties of aluminium diboride Al0.9B2". Journal of Solid State Chemistry. 177 (2): 389. Bibcode:2004JSSCh.177..389B. doi:10.1016/j.jssc.2002.12.001.
  4. ^ Hoffmann, R.-D.; Pöttgen, Rainer (2001-01-01). "AlB2-related intermetallic compounds – a comprehensive view based on group-subgroup relations". Zeitschrift für Kristallographie - Crystalline Materials. 216 (3). Walter de Gruyter GmbH: 127–145. Bibcode:2001ZK....216..127H. doi:10.1524/zkri.216.3.127.20327. ISSN 2196-7105. S2CID 98251655.