Is the Al-Pd-Mn icosahedral phase centrosymmetrical?

The possible non-centric character of the icosahedral Al-Pd-Mn phase has been checked by measuring Bijvoet pairs above the Pd K edge on a single grain. The integrated intensity of HKL and -H -K -L reflections is found to be identical within the experimental errors. The computed intensity variation for 45 degrees phase differences are computed to be much larger than the observed values. This indicates that the icosahedral phase is centrosymmetrical or presents phases very close to 0 or pi .