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Coupled substitution
Geological process by which two elements simultaneously substitute into a crystal / From Wikipedia, the free encyclopedia
Coupled substitution is the geological process by which two elements simultaneous substitute into a crystal in order to maintain overall electrical neutrality and keep the charge constant.[1] In forming a solid solution series, ionic size is more important than ionic charge, as this can be compensated for elsewhere in the structure.[2]
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replaces Si4+
and Ca2+
for Na+