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Controls on Morphology of Analcime‐Pollucite in Natural Minerals, Synthetic Phases, and Nuclear Waste Products
Author(s) -
Teertstra D. K.,
Černý P.
Publication year - 1992
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170270709
Subject(s) - analcime , alkalinity , morphology (biology) , divalent , chemistry , crystallography , leucite , inorganic chemistry , mineralogy , geology , zeolite , ceramic , paleontology , biochemistry , organic chemistry , catalysis
Crystals of the analcime‐pollucite series (NaAlSi 2 O 6 · H 2 OCsAlSi 2 O 6 ) exhibit tetragon‐trioctahedral {211} and hexahedral {100} morphology, with rare modification by tetrahexahedral {210} or rhombic dodecahedral {110} forms. Under weakly acidic to weakly basic conditions {100} is dominant; with increasing alkalinity (cation concentration), basicity (pH), and temperature {211} is dominant over {100}, with minor development of {210}. The morphology does not appear to be influenced by broad ranges in Si/Al (from 2.0 to 2.6 in the natural minerals) and Na‐Cs contents between analcime and pollucite, by substitutions of univalent cations Li, K, Rb, and Tl, or by small amounts of divalent cations Mg, Mn, Ni, Zn, Fe. Larger amounts of Ca, however, and possible substitutions for framework Al and Si seem to produce a more complex morphology.