  We present a selection of x-ray and neutron diffraction patterns of spherical
(He, Ar), dumbbell- (N2, CO), and chain-like molecules (n-C9H20, n-C19H40)
solidified in nanopores of silica glass (mean pore diameter 7nm). These
patterns allow us to demonstrate how key principles governing crystallization
have to be adapted in order to accomplish solidification in restricted
geometries. He, Ar, and the spherical close packed phases of CO and N2 adjust
to the pore geometry by introducing a sizeable amount of stacking faults. For
the pore solidified, medium-length chain-like n-C19H40 we observe a close
packed structure without lamellar ordering, whereas for the short-chain C9H20
the layering principle survives, albeit in a modified fashion compared to the
bulk phase.
