  We search for global rotation of the intracluster medium (ICM) in the galaxy
cluster Abell 2107, where previous studies have detected rotational motion in
the member galaxies with a high significance level. By fitting the centroid of
the iron $K_{\alpha}$ line complex at 6.7--6.9 keV rest frame in {\sl Chandra}
ACIS-I spectra, we identify the possible rotation axis with the line that
maximizes the difference between the emission-weighted spectroscopic redshift
measured in the two halves defined by the line itself. Then, we measure the
emission-weighted redshift in linear regions parallel to the preferred rotation
axis, and find a significant gradient as a function of the projected distance
from the rotation axis, compatible with a rotation pattern with maximum
tangential velocity ${\tt v}_{\rm max}=1380\pm 600$ km/s at a radius
$\lambda_0\sim 160$ kpc. This result, if interpreted in the framework of
hydrostatic equilibrium, as suggested by the regular morphology of Abell 2107,
would imply a large mass correction of the order of $\Delta M = (6 \pm 4)\times
10^{13} M_\odot$ at $\sim 160$ kpc, which is incompatible with the cluster
morphology itself. A more conservative interpretation may be provided by an
unnoticed off-center, head-on collision between two comparable halos. Our
analysis confirms the peculiar dynamical nature of the otherwise regular
cluster Abell 2107, but is not able to resolve the rotation vs merger scenario,
a science case that can be addressed by the next-generation X-ray facilities
carrying X-ray bolometers onboard.
