Silicon has been isomorphously substituted by aluminium and gallium in
the microporous titanosilicate ETS-10 to produce ETAS-10 and ETGS-10
respectively. For aluminium substitution a series of samples have been
prepared with Al/Ti ratios ranging from 0.10 to 0.48. Both aluminium
and gallium substitute exclusively in tetrahedral silicon sites in a m
anner which avoids Ti-O-Al and Ti-O-Ga linkages. Based upon detailed a
nalysis of solid-state NMR spectra, models for the ordering of alumini
um in ETAS-10 are discussed.