The experimental findings of this work suggest that ETS-4 is structure
related to zorite but is not the synthetic counterpart of this minera
l, as proposed previously. Si-29 MAS n.m.r. results are not entirely i
n agreement with the zorite structure. These spectroscopic results can
be explained by the presence of a second intergrown phase that would
not easily be observed by techniques such as scanning electron microsc
opy. X-ray diffraction patterns of zorite and ETS-LF are, however, ver
y similar. Two approaches have been taken to speculate on the structur
e of this material. First, ETS-4 is viewed as an intergrowth system of
zorite with nenadkevichite. The second approach derives mainly from t
he work on ETS-10 where a number of defects were observed in the HREM
images of this material. Combining both approaches seems to be a poten
tial way of explaining the structure of ETS-4.