Clays intercalated with both organic cations and hydroxy-metal cations, also known as inorganic-organic clays (IOCs), have drawn great interests in the recent years because they possess the properties of both organoclays and pillared layered clays (PILCs). In this work, cetyltrimethyl ammonium bromide (CTMAB) and hydroxy-aluminum ([Al13O4(OH)(24)(H2O)(12)](7+) or Al-13) were selected as the representatives of organic cations and hydroxy-metal cations, and three different methods were employed for the intercalation of montmorillonite at various CTMAB/Al-13 ratios. This Work aims to provide some novel information for clarifying the structural characteristics of IOCs. The experimental results showed that the structures of the resulting IOCs strongly depended on the intercalation methods and cTMAB/Al-13 ratio. Both the intercalation agents could be intercalated into montmorillonite if they were used simultaneously for the intercalation agents could be intercalated into montmorillonite if they were used simultaneously for the intercalation, or if Al-13 was intercalated after CTMAB, and the resulting IOCs were shown to have large basal spacing and small surface areas. However, if Al-13 was intercalated first, the loading amounts of CTMAB would decrease significantly when the used Al-13 amounts were relatively large (>= 4 mmol Al/g montmorillonite). This could be attributed to the "lock" effect of montmorillonite's layers by the pre-intercalated Al-13, and the basal spacing Values of the resulting IOCs were shown to be equal to those of the PILCs. (C) 2009 Elsevier Inc. All rights reserved.