Accurate structure-factor measurements using high-energy synchrotron radiation: a test on cuprite, Cu2O

Using high-energy synchrotron radiation, structure factors were measured on the triple-axis diffractometer at the HASYLAB beamline BW5. A data set for cuprite, Cu2O, was recorded, and the excellent data quality [internal cons istency R-int(F-2) = 0.0055] allowed full multipole refinements using the p rogram VALRAY. Extinction was still significant, but small. Using data meas ured at 75, tao, 125 and 150 keV photon energies, it was possible to determ ine and separate extinction prior to the refinements. After evaluation and comparison of extinction-affected and extinction-free data, significant dif ferences in the electron densities were found.