Barrerite from Alaska was investigated by Si-29, Al-27 and Na-23 MAS NMR bo
th in its untreated (as-found) and heated forms. The chemical shift of the
Si-29 NMR lines of the natural phase revealed the presence of three differe
nt Si(nAl) configurations. The Al-27 NMR signal of the natural phase, posit
ioned in the region of tetrahedrally coordinated Al, becomes more shielded
with increasing temperature, in agreement with the changes of the Al-O-Si b
ond angles caused by the distortion of the framework observed by means of X
-ray diffraction (Alberti & Vezzalini, 1978). Changes in the Al-27 NMR line
-width were also correlated to dehydration at high temperature. Al-27 2D tr
iple-quantum MAS NMR spectra were recorded on natural and dehydrated barrer
ite. In neither case the five tetrahedral sites could be differentiated by
the MQMAS technique. Na-23 MAS spectra were preliminarily collected on the
untreated barrerite and on the sample heated at 450 degreesC and the shift
of the resonance line towards higher fields in the heated phase was interpr
eted as a consequence of the heating process and of the increased coordinat
ion number.