Interactions in sphere packings

The circle packings including non-periodic packings and 41 homogeneous sphe re packings with 4 less than or equal to T-1 less than or equal to 12 conta cts are analyzed for physical and thermodynamic stability. The two- and thr ee-dimensional structures A(x)B(y) can be characterized by the numbers T-1 and T-2 of nearest and next-nearest neighbors of the same kind. A small num ber of structures at the border of the T-1. T-2 structure maps is stabilize d by enthalpy compared to an increased number of entropy stabilized structu res. The self-coordination numbers T-1 correspond to the numbers of contact s for sphere packing.