Infrared Study of Compounds and Solid Solutions in the System Lithia–Alumina–Silica

The system Li 2 O‐Al 2 O 3 ‐SiO 2 contains several compounds and solid solutions which are important commercially and which are also of interest from a structural point of view. In addition to the interesting polymorphic modifications exhibited by spodumene and eucryptite, the solid solutions between spodumene and eucryptite and more particularly the solid solutions between spodumene and silica (the so‐called silica‐O series) constitute a group of materials quite suitable for studying the applicability of infrared methods for structural interpretations. The infrared spectra of all the compounds and some typical solid solutions have been obtained and the relations between these spectra and the structures as determined by X‐ray methods are discussed.