| Abstract
| - We have carried out a percolation analysis of the adsorption of ethane and nitrogen in SBA-2, a structuredmesoporous silica consisting of a hexagonal close-packed (hcp) array of spherical cavities connected bycylindrical channels. Our analysis explains the different uptakes of nitrogen and ethane in terms of thegreater accessibility of the network to the smaller nitrogen molecule. The analysis also allows us to quantifythe connectivity of the SBA-2 pore network. The effective coordination number of the cavities, defined asthe average number of channels per cavity that are large enough to allow nitrogen to pass, is 4.9, muchless than the theoretical maximum value of 12. Taking into account only the smaller set of channels largeenough to admit ethane, the effective coordination number is 1.8, just above the percolation threshold ofthe network.
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