Cystallography and databases:

The Collaborative Computational Project. A very useful site for free crystallographic software:

The Bilbao Crystallographic Server. A web-based set of crystallographic tools and a handy place to find the contents of the all the space groups:

American Mineralogist Crystal Structure Database. Download CIFs, visualize crystal structures, and download PDFs of the published papers. Its all here for free:

X-Ray and neutron scattering:

The Total Scattering Group (Los Alamos National Lab, Lujan Neutron Center). All the software and tools for doing pair distribution function (PDF) analysis:

Planning on neutron experiment? Check the table to see scattering and absorption cross sections of the elements in your compound(s):

Other labs and centers at the Univeristy of Maryland:

The X-ray Crystallography Center:

The Center for Nanophysics and Advanced Materials:

The Univeristy of Maryland Energy Research Center:

The Energy Frontier Research Center:

The Chemical Physics Program: