Synthesis, structure determination and properties of MIL-53as and MIL-53ht: the first Criii hybrid inorganic–organic microporous solids: Criii(OH)·{O2C–C6H4–CO2}·{HO2C–C6H4–CO2H}xElectronic supplementary information (ESI) available: crystal data, atomic coordinates and metrical parameters for MIL-53as and MIL-53ht. See http://www.rsc.org/suppdata/cc/b2/b201381a/

The first three-dimensional chromium(III) dicarboxylate compounds have been isolated and their structures solved from powder X-ray diffraction data; the flexible framework of these materials delimits large pores.