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Cover Picture: Spectroscopic and Computational Characterizations of Alkaline‐Earth‐ and Heavy‐Metal‐Exchanged Natrolites (ChemPlusChem 8/2014)
Author(s) -
Liu Dan,
Chen Xin,
Ma Yanming,
Liu Zhenxian,
Vogt Thomas,
Lee Yongjae
Publication year - 2014
Publication title -
chempluschem
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201402164
Subject(s) - alkaline earth metal , zeolite , alkali metal , chemistry , crystallography , ring (chemistry) , divalent , molecule , cover (algebra) , metal , earth (classical element) , ring size , ion , inorganic chemistry , physics , organic chemistry , catalysis , mechanical engineering , engineering , mathematical physics
The cover picture shows the natrolite framework of a small‐pore zeolite made up of alternating SiO 4 and AlO 4 tetrahedral 4‐rings and helical 8‐rings, which can contain, via cooperative rotation of the 4‐rings and subsequent modification of the 8‐ring opening, monovalent alkali metals Li + , Na + , K + , Rb + and Cs + , divalent alkaline‐earth ions Ca 2+ , Sr 2+ and Ba 2+ as well as heavy metals like Cd 2+ , Pb 2+ and Ag + as charge‐balancing extra‐framework cations (EFC). In their Full Paper on on page 1096 ff. , Y. Lee and co‐workers report that the vibrational frequencies of both 4‐ and helical 8‐ring units scale with the size of the EFC and that the frequency of the HOH bending and OH stretching modes of water contained within the pores are dependent on the orientations of the water molecules along the natrolite channel. Deviations from these correlations in mixed EFC natrolites could hint at new structures owing to size‐driven phase separations.