Data di Pubblicazione:
1988
Abstract:
Four diflerent natural crystals of thortveitite (Sc,Y)2Si2O7, have been analyzed by electron
microprobe, and the structure has been determined from single-crystal data using
MoKa radiation up to at least d : 40". The form factor of the metal has been derived from
the chemical analysis of each crystal. The final disagreement factor R : > | 14 | - 14 |
l/>lF"l is around 0.02; the standardd eviationso f the bond distancesa re between0 .001
and 0.002 A, and those of the angles are around 0.1". The Si-O-Si angle is indeed 180.;
the crystal symmetry is C2/m, and there is no evidence for disorder involving the SirO,
group; the analytical data indicate extensive substitution of Y and REE for Sc, as well as
nonnegligible amounts of Zr and Hf; the charge balance is maintained by multiple substitution
of Ca, Mg, and Mn in the metal position and of Al for Si.
microprobe, and the structure has been determined from single-crystal data using
MoKa radiation up to at least d : 40". The form factor of the metal has been derived from
the chemical analysis of each crystal. The final disagreement factor R : > | 14 | - 14 |
l/>lF"l is around 0.02; the standardd eviationso f the bond distancesa re between0 .001
and 0.002 A, and those of the angles are around 0.1". The Si-O-Si angle is indeed 180.;
the crystal symmetry is C2/m, and there is no evidence for disorder involving the SirO,
group; the analytical data indicate extensive substitution of Y and REE for Sc, as well as
nonnegligible amounts of Zr and Hf; the charge balance is maintained by multiple substitution
of Ca, Mg, and Mn in the metal position and of Al for Si.
Tipologia CRIS:
01.01 Articolo in rivista
Elenco autori:
Diella, Valeria
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