TY - JOUR
T1 - Aluminum substitution in MgSiO3 perovskite
T2 - Investigation of multiple mechanisms by 27Al NMR
AU - Stebbins, Jonathan F.
AU - Kojitani, Hiroshi
AU - Akaogi, Masaki
AU - Navrotsky, Alexandra
N1 - Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2003/7
Y1 - 2003/7
N2 - In the Earth's mantle, the mechanism(s) of solid solution of Al in MgSiO3 perovskite strongly impacts its thermodynamic and transport properties. We present 27Al NMR data for perovskite samples of nominal composition Mg(Si0.9Al0.1 O2.95, to test a mechanism by which Al3+ substitutes at the octahedral Si4+ sites, leaving a corresponding number of O-site vacancies. We find evidence for this process in a significantly greater peak area for Al at B (Si) sites vs. A (Mg) sites in the structure, and the possible identification of a small concentration of five-coordinated Al adjacent to such vacancies. However, substitution of Al3+ at the A sites remains significant. As in perovskite-type technological ceramics, O-atom vacancies may play an important role in enhancing ion mobility and the dissolution of water.
AB - In the Earth's mantle, the mechanism(s) of solid solution of Al in MgSiO3 perovskite strongly impacts its thermodynamic and transport properties. We present 27Al NMR data for perovskite samples of nominal composition Mg(Si0.9Al0.1 O2.95, to test a mechanism by which Al3+ substitutes at the octahedral Si4+ sites, leaving a corresponding number of O-site vacancies. We find evidence for this process in a significantly greater peak area for Al at B (Si) sites vs. A (Mg) sites in the structure, and the possible identification of a small concentration of five-coordinated Al adjacent to such vacancies. However, substitution of Al3+ at the A sites remains significant. As in perovskite-type technological ceramics, O-atom vacancies may play an important role in enhancing ion mobility and the dissolution of water.
UR - http://www.scopus.com/inward/record.url?scp=0042066680&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0042066680&partnerID=8YFLogxK
U2 - 10.2138/am-2003-0724
DO - 10.2138/am-2003-0724
M3 - Article
AN - SCOPUS:0042066680
SN - 0003-004X
VL - 88
SP - 1161
EP - 1164
JO - American Mineralogist
JF - American Mineralogist
IS - 7
ER -