Strong negative thermal expansion in the siliceous zeolites ITQ-1, ITQ-3 and SSZ-23

Strong negative thermal expansion has been found for the pure SiO 2 zzeolites ITQ-1 (α v =–12.1×10 –6 K –1 ), SSZ-23 (α v =–10.3×10 –6 K –1 ) and ITQ-3 (α v =–11.4×10 –6 K –1 ) from 50 to 500 °C and above.