The wavelength of the X-ray beam is about the same order as the atomic distances. The X-ray is, therefore, the most suitable 'light' for the investigation of the world of molecules. Just like we could investigate the world of bacteria by the microscope using visible light, we can investigate the world of molecules by the X-ray beam.
Since the lens for focusing the X-ray is not available, we can not make an X-ray microscope.
Instead
of using lens, we detect the diffraction and create an image of the molecule
with the help of computer.