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AlH3 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Al3+ is bonded to six equivalent H1- atoms to form corner-sharing AlH6 octahedra. The corner-sharing octahedral tilt angles are 39°. All Al–H bond lengths are 1.72 Å. H1- is bonded in a bent 150 degrees geometry to two equivalent Al3+ atoms.
AlH3 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six H1- atoms to form a mixture of edge and corner-sharing AlH6 octahedra. The corner-sharing octahedra tilt angles range from 0–46°. There are a spread of Al–H bond distances ranging from 1.69–1.77 Å. In the second Al3+ site, Al3+ is bonded to six H1- atoms to form corner-sharing AlH6 octahedra. The corner-sharing octahedra tilt angles range from 11–46°. There is four shorter (1.72 Å) and two longer (1.76 Å) Al–H bond length. There are four inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted bent 120 degrees geometry to two Al3+ atoms. In the second H1- site, H1- is bonded in a water-like geometry to two equivalent Al3+ atoms. In the third H1- site, H1- is bonded in a linear geometry to two Al3+ atoms. In the fourth H1- site, H1- is bonded in a linear geometry to two equivalent Al3+ atoms.
AlH3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six H1- atoms to form corner-sharing AlH6 octahedra. The corner-sharing octahedra tilt angles range from 38–44°. There are a spread of Al–H bond distances ranging from 1.72–1.74 Å. In the second Al3+ site, Al3+ is bonded to six H1- atoms to form corner-sharing AlH6 octahedra. The corner-sharing octahedra tilt angles range from 39–44°. There is four shorter (1.73 Å) and two longer (1.74 Å) Al–H bond length. There are four inequivalent H1- sites. In the first H1- site, H1- is bonded in a bent 150 degrees geometry to two Al3+ atoms. In the second H1- site, H1- is bonded in a bent 150 degrees geometry to two equivalent Al3+ atoms. In the third H1- site, H1- is bonded in a bent 150 degrees geometry to two equivalent Al3+ atoms. In the fourth H1- site, H1- is bonded in a bent 150 degrees geometry to two equivalent Al3+ atoms.
AlH3 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Al3+ is bonded to six equivalent H1- atoms to form corner-sharing AlH6 octahedra. The corner-sharing octahedral tilt angles are 44°. All Al–H bond lengths are 1.72 Å. H1- is bonded in a bent 150 degrees geometry to two equivalent Al3+ atoms.
An efficient method for various noniterative estimates of connected triple excitations in coupled-cluster theory is outlined and related to a similar expression occurring in Moller-Plesset perturbation theory. The method is highly vectorized and capable of utilizing multiple processors on a shared-memory machine, leading to computational rates in excess of one billion floating-point operations per second on four processors of a CRAY Y-MP. Using the new procedure, the binding energies of the D(2h) diborane-type dimers of AlH3, AlH2F, AlHF2, and AlF3 have been determined to be 32, 40, 20, and 47 kcal/mol, respectively. For Al2F6, the correlation procedure includes 232 molecular orbitals and over 1.5 x 10 to the 6th single and double coupled-cluster amplitudes, effectively accounting for over 2 x 10 to the 9th connected triple excitations.
Several solid state NMR techniques including magic-angle-spinning (MAS) and multiple-quantum (MQ) MAS experiments have been used to characterize various AlH3 samples. MAS-NMR spectra for the 1H and 27Al nuclei have been obtained on a variety of AlH3 samples that include the (beta)- and (gamma)- phases as well as the most stable (alpha)-phase. While the dominant components in these NMR spectra correspond to the aluminum hydride phases, other species were found that include Al metal, molecular hydrogen (H2), as well as peaks that can be assigned to Al-O species in different configurations. The occurrence and concentration of these extraneous components are dependent upon the initial AlH3 phase composition and preparation procedures. Both the (beta)-AlH3 and (gamma)-AlH3 phases were found to generate substantial amounts of Al metal when the materials were stored at room temperature while the (alpha)-phase materials do not exhibit these changes.
(AlH3(CO2)3)8(CO2)6O2 crystallizes in the cubic Im-3 space group. The structure is three-dimensional and consists of six carbon dioxide molecules, two water molecules, and one AlH3(CO2)3 framework. In the AlH3(CO2)3 framework, Al3+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Al–O bond lengths are 1.91 Å. C+2.53+ is bonded in a trigonal planar geometry to one H1+ and two equivalent O2- atoms. The C–H bond length is 1.10 Å. Both C–O bond lengths are 1.27 Å. H1+ is bonded in a single-bond geometry to one C+2.53+ atom. O2- is bonded in a bent 120 degrees geometry to one Al3+ and one C+2.53+ atom.