electronic reprint Acta Crystallographica Section A Foundations and Advances ISSN 2053-2733 About systematic errors in charge-density studies Julian Henn and Kathrin Meindl Acta Cryst. (2014). A70, 248–256 Copyright c International Union of Crystallography Author(s) of this paper may load this reprint on their own web site or institutional repository provided that this cover page is retained. Republication of this article or its storage in electronic databases other than as specified above is not permitted without prior permission in writing from the IUCr. For further information see http://journals.iucr.org/services/authorrights.html Acta Crystallographica Section A: Foundations and Advances publishes articles report- ing f undamental advances in all areas of crystallography in the broadest sense. This includes metacrystals such as photonic or phononic crystals, i.e. structures on the meso- or macroscale that can be studied with crystallographic methods. The central themes are, on the one hand, experimental and theoretical studies of the properties and arrangements of atoms, ions and molecules in condensed matter, periodic, quasiperiodic or amorphous, ideal or real, and, on the other, the theoretical and experimental aspects of the various methods to determine these properties and arrangements. In the case of metacrystals, the focus is on the methods for their creation and on the structure–property relationships for their interaction with classical waves. Crystallography Journals Online is available from journals.iucr.org Acta Cryst. (2014). A70, 248–256 Henn and Meindl · Systematic errors in charge-density studies