Helium cryostat synchrotron charge densities determined using a large CCD detector -- upgraded beamline D3 at DESY.

A 165 mm Mar CCD detector has been fitted on a large Huber four-circle diffractometer together with a helium cryostat at beamline D3 at Hasylab, DESY in Hamburg. This setup allows fast collection of accurate, shortwavelength, very low temperature X-ray diffraction data for charge-density analysis. As a test example, diffraction data have been collected in 10 h on a hydrogen-bonded network system with 15 unique atoms, and the electron density was modelled with the multipole formalism in an X-N procedure using matching-temperature neutron diffraction data collected at Institut Laue Langevin, Grenoble in France. [ABSTRACT FROM AUTHOR]