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–CO2HxElectronic 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/ | Synapse