TY - JOUR
T1 - Towards better analogues for MgSiO3 post-perovskite
T2 - NaCoF3 and NaNiF3, two new recoverable fluoride post-perovskites
AU - Dobson, David P.
AU - Hunt, Simon A.
AU - Lindsay-Scott, Alexander
AU - Wood, Ian G.
PY - 2011/12
Y1 - 2011/12
N2 - We present details of two new quenchable post-perovskite-structured NaBF3 compounds, where B is Co or Ni. Both post-perovskites are readily synthesised in the multi-anvil-press pressure range and have unit cells with axial ratios similar to MgSiO3 post-perovskite (NaCoF3 a=3.07035(7) Å, b=10.1291(3) Å, c=7.4664(1) Å, V=232.20(1) ų; NaNiF3 a=3.0247(2) Å, b=10.0543(7) Å, c=7.3989(3) Å, V=225.01(3) ų). For NaCoF3 , we have synthesised post-perovskite single crystals and determined the phase diagram: the perovskite-post-perovskite transition occurs at 18GPa and 700°C, with a Clapeyron slope of 15.5MPa/K. On the basis of the above factors, combined with (1) the fact that ABF3 compositions also have stable perovskite phases and (2) the relatively small differences in the mass ratios of their constituent atoms, we suggest that these systems might prove to be better analogues for MgSiO 3 post-perovskite than the currently used CaBO3 (where B is Ir, Pt, Rh, Ru) compositions.
AB - We present details of two new quenchable post-perovskite-structured NaBF3 compounds, where B is Co or Ni. Both post-perovskites are readily synthesised in the multi-anvil-press pressure range and have unit cells with axial ratios similar to MgSiO3 post-perovskite (NaCoF3 a=3.07035(7) Å, b=10.1291(3) Å, c=7.4664(1) Å, V=232.20(1) ų; NaNiF3 a=3.0247(2) Å, b=10.0543(7) Å, c=7.3989(3) Å, V=225.01(3) ų). For NaCoF3 , we have synthesised post-perovskite single crystals and determined the phase diagram: the perovskite-post-perovskite transition occurs at 18GPa and 700°C, with a Clapeyron slope of 15.5MPa/K. On the basis of the above factors, combined with (1) the fact that ABF3 compositions also have stable perovskite phases and (2) the relatively small differences in the mass ratios of their constituent atoms, we suggest that these systems might prove to be better analogues for MgSiO 3 post-perovskite than the currently used CaBO3 (where B is Ir, Pt, Rh, Ru) compositions.
KW - ABF fluorides 3
KW - Multi-anvil press
KW - Post-perovskite
U2 - 10.1016/j.pepi.2011.08.010
DO - 10.1016/j.pepi.2011.08.010
M3 - Article
SN - 0031-9201
VL - 189
SP - 171
EP - 175
JO - Physics of the Earth and Planetary Interiors
JF - Physics of the Earth and Planetary Interiors
IS - 3-4
ER -