[en] Using the recently implemented and tested non-muffin-tin scattered-wave method of Natoli et al. we calculated the Cr K-edge XANES of the model system chromium hexacarbonil, to determine the size and nature of non-muffin-tin corrections, and to get some idea of the seriousness of the remaining approximations in current ab initio calculations. After summarizing progress with the non-muffin-tin method the results of calculations of chromium hexacarbonyl are presented, discussing their significance and the implications for XANES calculations in general. In particular a previously hidden sensitivity of the results to detail of the construction of the one-electron potential is reported