Retraction of articles.

This article reports the retraction of five articles published in Acta Crystallographica Section E between 2004 and 2011.

After further thorough investigation (see Harrison et al., 2010 ▶), five articles are retracted as a result of problems with the data sets or incorrect atom assignments. Full details of all the articles are given in Table 1 ▶.

Table 1

Details of articles to be retracted, in order of publication

Title	Reference	DOI	Refcode
Ammonium 2,6-dicarboxy-4-nitrophenolate	Sun & Nie (2004 ▶)	10.1107/S1600536804022135	PAHDUY
Triaqua(1,10-phenanthroline)sulfatocopper(II) monohydrate	An et al. (2007 ▶)	10.1107/S1600536807000591	HEWQUW
Diaqua-1κO,3κO-di-μ-cyanido-1:2κ2N:C;2:3κ2C:N-dicyanido-2κ2C-bis{4,4′-dibromo-2,2′-[propane-1,2-diylbis(nitrilomethylidyne)]diphenolato}-1κ4O,N,N′,O′;3κ4O,N,N′,O′-1,3-diiron(III)-2-nickel(II)	Zhang et al. (2008 ▶)	10.1107/S1600536808017893	SOGBOG
Bis(6-methoxy-2-{[tris(hydroxymethyl)methyl]iminomethyl}phenolato)copper(II) dihydrate	Zhang et al. (2009 ▶)	10.1107/S1600536808043948	ROLPAK
Oxonium picrate	Jin et al. (2011 ▶)	10.1107/S1600536811022574	EVILAX