Mesoporous silica with Ia3d cubic structure and good thermal stabilityElectronic Supplementary Information (ESI) available: XRD and N2 sorption isotherms of the as-synthesized powders calcined in air at 900 �C for 4 h, and the as-synthesized powders calcined in air at 500 �C for 6 h and then calcined in air or nitrogen at 900 �C for 4 h; XRD of the as-synthesized powders when the molar ratio of DM?CTAB is 1?2; EDS spectrum and TGA curve of the powders carbonized in nitrogen at 900 �C for 4 h; proposed formation mechanism of the Ia3d cubic mesostructure in nitrogen at high temperatures such as 900 �C. See http://www.rsc.org/suppdata/cc/b3/b316501a/