An X-ray single crystal study of alkaline cations influence on laumontite hydration ability: I. Humidity-induced hydration of Na,K-rich laumontite

作者：Rashchenko Sergey V^*; Seryotkin Yurii V; Bakakin Vladimir V

来源：Microporous and Mesoporous Materials, 2012, 151: 93-98.

DOI：10.1016/j.micromeso.2011.11.009

• Zeolite
• Laumontite
• Crystal structure
• Hydration
• Humidity

The crystal structure of natural Na,K-rich variety of zeolite laumontite was refined from single-crystal X-ray data obtained at relative humidity (RH) of 30%, 45%, 70% and with crystal submerged in water. The strong evidences of humidity-induced hydration were obtained: the amount of H2O molecules per unit cell increased from 12.0 at RH of 30% to 13.4 at submerging in water, with corresponding increase of unit cell volume by 1.4%. It disproves the common opinion that Na,K-rich laumontite is characterized by incapability of hydration. %26lt;br%26gt;The ordinary Ca-laumontite vertical bar Ca-4(H2O)(n)vertical bar[Al8Si16O48] hydrates abruptly from 14 to 18 H2O molecules per unit cell at RH of 60-70% due to the sharp occupation of a vacant water site. In contrast, Na,K-rich laumontite demonstrated regular and less intensive hydration in studied RH range due to the slight occupancy increase of already populated water sites. The comparative analysis of H-bond nets in Ca-laumontite and Na,K-rich laumontite showed the similarity in H-bonding between Na,K-rich laumontite and high-hydrated form of Ca-laumontite.

• 出版日期2012-3-15