A new activity model for biotite and its application.

ABSTRACT: A new activity model for biotite is formulated in the system K₂O-FeO-MgO-Al₂O₃-SiO₂-H₂O-TiO₂-O₂ (KFMASHTO), which extends that for the KFMASH system by introducing a titanium-biotite and a ferric-biotite end-member (tbio: K(TiMg₂)[(O)₂(AlSi₃)O₁₀] and fbio: K(Fe³⁺Mg₂)[(OH)₂(Al₂Si₂)O₁₀]), as well as a pyrophyllite end-member (pyp: Al₂[(OH)₂Si₄O₁₀]) that accounts for the presence of octahedral excess-Al in natural biotites. Phonon calculations applying density functional theory (DFT) using the software Castep yielded the standard entropie

SUBMITTER: Dachs E 

PROVIDER: S-EPMC11452188 | biostudies-literature | 2024

REPOSITORIES: biostudies-literature