The reaction of the oligoalumosiloxane [Ph
2
SiO]
8
[AlO(OH)]
4
(
1
) with hexamethyldisilazane leads to the triple ionic [Ph
2
SiO]
8
[AlO
2
]
2
[AlO(O-SiMe
3
)]
2
[NH
4
-THF]
2
∙2 THF (
2
) and in the presence of pyridine to [Ph
2
SiO]
8
[AlO
1.5
]
4
∙2py∙1.5 C
7
H
8
(
3
). Apart from the usual characterization techniques (NMR and IR spectroscopy) the molecular structures of
2
and
3
have been determined by single-X-ray diffraction analyses. Both alumosiloxanes
2
and
3
present new types of molecular structures with a central four membered Al
2
O
2
-ring, on which the further aluminium atoms are attached via oxygen atoms. This leads to an Al
4
-lozenge, which is centered in subtriangles by oxygen atoms.