  During cluster mergers, the intracluster gas and member galaxies undergo
dynamic evolution, but at different timescales and reach different states. We
collect 24 galaxy clusters in quasi-equilibrium state as indicated by the X-ray
image, and calculate the cluster orientations and three kinds of dynamical
parameters, i.e., the normalized centroid offset, the sphere index and the
ellipticity, for these clusters from the distributions of member galaxies and
also the intracluster gas. We find consistent alignments for the orientations
estimated from the two components. However, the three kinds of dynamical
parameters indicated by member galaxies are systematically larger than those
derived from the gas component, suggesting that the gas component is more
relaxed than member galaxies. Differences of dynamical features between the
intracluster gas and member galaxies are independent of cluster mass and
concentration. We conclude that the intracluster gas reaches the dynamic
equilibrium state earlier than the almost collisionless member galaxies.
