Influence of content of pressure-transmitting medium on structural evolution of heulandite: Single-crystal X-ray diffraction study

摘要

The structural evolution of natural heulandite Ca2.90Na2.07Sr0.25K0.16Ba0.06(H2O)(n)[Al8.65Si27.35O72] was studied upon compression in penetrating (water-containing) and non-penetrating (paraffin) media using single-crystal X-ray diffraction data in a diamond-anvil cell. Compression in a water-containing medium results in an additional hydration of heulandite from 23 molecules per unit cell at ambient conditions to approximate to 27 at 3.27 GPa. Water molecules enter both initially vacant and partly occupied positions. Additional hydration stabilizes the crystal structure decreasing its compressibility. (C) 2015 Elsevier Inc. All rights reserved.