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Close-packing of particles results in two highly efficient lattices, hexagonal close-packed (hcp) and cubic close-packed (ccp). The ccp lattice is also called face-centred cubic (fcc).

In both these packings, 74% of the space is filled. The remaining space is present in the form of two types of voids-octahedral and tetrahedral. The efficient packing results in a high density of solids. Other types of packing are not closed packing and have less efficient packing of particles. In body-centred cubic lattice (bcc), 68% of space is filled whereas simple cubic has 52% of space filled.