  RBS797 and CL 0939+4713 are two intermediate red-shift clusters
($z=0.35-0.41$). They have very different morphologies but both show
surprisingly interesting structures. RBS797 looks relaxed, with an almost
circular morphology; a CHANDRA observation of this cluster has revealed two
deep depressions in the X-ray emission near the core. CL 0939+4713 has instead
an irregular morphology with evident substructures which seem to be in the
process of merging.
