Aluminium hydride

Aluminium hydride
Unit cell spacefill model of aluminium hydride
Names
Preferred IUPAC name
Aluminium hydride
Systematic IUPAC name
Alumane
Other names
  • Alane
  • Aluminic hydride
  • Aluminium(III) hydride
  • Aluminium trihydride
  • Trihydridoaluminium
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.029.139 Edit this at Wikidata
245
UNII
  • InChI=1S/Al.3H checkY
    Key: AZDRQVAHHNSJOQ-UHFFFAOYSA-N checkY
  • InChI=1S/Al.3H
    Key: AZDRQVAHHNSJOQ-UHFFFAOYSA-N
  • InChI=1/Al.3H/rAlH3/h1H3
    Key: AZDRQVAHHNSJOQ-FSBNLZEDAV
  • [AlH3]
Properties
AlH3
Molar mass 30.006 g·mol−1
Appearance white crystalline solid, non-volatile, highly polymerized, needle-like crystals
Density 1.477 g/cm3, solid
Melting point 150 °C (302 °F; 423 K) starts decomposing at 105 °C (221 °F)
reacts
Solubility soluble in ether
reacts in ethanol
Thermochemistry
40.2 J/(mol·K)
30 J/(mol·K)
−11.4 kJ/mol
46.4 kJ/mol
Related compounds
Related compounds
 Lithium aluminium hydride, diborane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Aluminium hydride (also known as alane and alumane) is an inorganic compound with the formula AlH3. Alane and its derivatives are part of a family of common reducing reagents in organic synthesis based around group 13 hydrides.[1] In solution—typically in ethereal solvents such tetrahydrofuran or diethyl ether—aluminium hydride forms complexes with Lewis bases, and reacts selectively with particular organic functional groups (e.g., with carboxylic acids and esters over organic halides and nitro groups), and although it is not a reagent of choice, it can react with carbon-carbon multiple bonds (i.e., through hydroalumination). Given its density, and with hydrogen content on the order of 10% by weight,[2] some forms of alane are, as of 2016,[3] active candidates for storing hydrogen and so for power generation in fuel cell applications, including electric vehicles.[not verified in body] As of 2006 it was noted that further research was required to identify an efficient, economical way to reverse the process, regenerating alane from spent aluminium product.

Solid aluminium hydride, or alane, is colorless and nonvolatile, and in its most common reagent form it is a highly polymerized species (i.e., has multiple AlH3 units that are self-associated); it melts with decomposition at 110 °C.[4] While not spontaneously flammable, alane solids and solutions require precautions in use akin to other highly flammable metal hydrides, and must be handled and stored with the active exclusion of moisture. Alane decomposes on exposure to air (principally because of adventitious moisture), though passivation — here, allowing for development of an inert surface coating — greatly diminishes the rate of decomposition of alane preparations.[not verified in body]

  1. ^ Brown, H. C.; Krishnamurthy, S. (1979). "Forty Years of Hydride Reductions". Tetrahedron. 35 (5): 567–607. doi:10.1016/0040-4020(79)87003-9.
  2. ^ Cite error: The named reference h2storage was invoked but never defined (see the help page).
  3. ^ Lin-Lin Wang; Aditi Herwadkar; Jason M. Reich; Duane D. Johnson; Stephen D. House; Pamela Peña-Martin; Angus A. Rockett; Ian M. Robertson; Shalabh Gupta; Vitalij K. Pecharsky (2016). "Towards Direct Synthesis of Alane: A Predicted Defect-Mediated Pathway Confirmed Experimentally". ChemSusChem. 9 (17): 2358–2364. Bibcode:2016ChSCh...9.2358W. doi:10.1002/cssc.201600338. PMID 27535100.
  4. ^ Cite error: The named reference EROSv08 was invoked but never defined (see the help page).