Aluminium diboride

Aluminium diboride

Names
IUPAC name aluminium diboride
Other names aluminium boride
Identifiers
CAS Number	12041-50-8^Y
3D model (JSmol)	Interactive image
ChemSpider	21171253^Y
ECHA InfoCard	100.031.736
EC Number	234-923-7
PubChem CID	24884166
CompTox Dashboard (EPA)	DTXSID90898993
InChI InChI=1S/Al.B2/c;1-2/q-2;+2^Y Key: XGNZNBRDPPLKTC-UHFFFAOYSA-N^Y 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/cm^3[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 (S^⦵298)	34.7 J/mol K
Std enthalpy of formation (ΔfH^⦵298)	-151 kJ/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is ^YN ?) 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. 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 Al_0.9B₂". 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.

External links

• "Boron";