Molecular structures

By far the most popular type of investigation on VIVALDI to date has been location of hydrogen atoms or precise characterisation of water molecules in molecular structures with unit cells up to 10000 Å3 in volume. The gain in efficiency of one-to-two orders of magnitude over a conventional monochromatic diffractometer allows detailed atomic structural information to be obtained from crystals previously considered to be too small for neutron diffraction.

The left-hand figure below shows part of the molecular structure of [H4Co4(C5Me4Et)4] at 20 K, the first published result from VIVALDI. The existence of the hydrogen atoms around the Co cluster in this 8200 Å3 unit cell was proven from a three-day diffraction measurement on a crystal of just 0.6 mm3 in volume.

The right-hand figure shows the first observation of Li-encapsulated H in [(t-Bu2AlMe2)2Li]-[{Ph(2-C5H4N)N}6HLi8]+

  • R Bau, N N Ho, J J Schneider, S A Mason, and G J McIntyre, Inorg. Chem. 43 (2004) 555-558.
  • S R Boss, J M Cole, R Haigh, R Snaith, A E H Wheatley, G J McIntyre and P R Raithby, Organometallics 23 (2004) 4527-4530.