ABSTRACTCompressibility of anatase nano particles of TiO2 changes from the bulk counterpart. This has been associated with amorphization and compaction. The behavior of such systems under extreme conditions is examined using a shell partial distribution function and some comparison made with rutile and baddeylite polytypes based nano structures. Particle energies of rutile and baddeylite nano particles appear to be rather size independent as compared to the anatase polytypes. The latter is associated with large relaxations and re-bonding in the relatively soft anatase phase of nano TiO2.