Variation of the oxygen content and point defects in tephroite, Mn2SiO4+δ
作者： J. Töpfer , R. Dieckmann
DOI: 10.1016/J.SSI.2010.02.004
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摘要: Abstract Changes in the oxygen content of Mn 2 SiO 4 + δ equilibrium with MnSiO 3 were measured thermogravimetrically at 1000, 1100 and 1200 °C a total pressure about 0.5 atm as function activity, O , used to determine absolute values for . The obtained vary from 15 · 10 − 4 5 · 10 1000 °C high activities, below 1 · 10 log 10 ≈ − 8.5 both temperatures. Thus is non-stoichiometric over entire activity range investigated. deviation stoichiometry manganese silicate modeled based on formation localized holes, (Mn 2+ 3+ ) vacancies, ( V )″, 4+ ions silicon sites, Si x This defect model accounts observed dependence Furthermore, better understand dependencies point concentrations experimentally relevant conditions, calculations using more general performed derive Kroger–Vink diagrams generic orthosilicate Me constant Si/(Me + Si)-ratios being second oxide type MeSiO
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