The crystal structure of wollastonite.
End-Member Wollastonite Bustamite Rhodonite Pyroxmangite Ferrosilite III Formula Al2SiO5 Al2SiO5 Al2SiO5 Al2SiO4(F,OH)2 |
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Mineral Data Base Index
Mineral Structure Data
The Pyroxenoid group is composed of minerals of the general formula
XnSinO3n,
where X is a large-radius divalent cation, typically Ca, Mn, or Fe.
The symmetry is triclinic and results from a mismatch between the
sizes of the divalent cation and the silicate chain. The repeat
integer n, increases as the mean size of the divalent cation decreases.
For wollastonite and bustamite, n = 3, for rhodonite, n = 5, for
pyroxmangite and pyroxferroite, n = 7, and for ferrosilite III, n = 9.
In addition to the above anhydrous proxenoids, there is also a series of
hydrous pyroxenoids in which Na + H substitute for one of the divalnet cations
giving us pectolite (NaHCa
The crystal structure of wollastonite.
End-Member Wollastonite Bustamite Rhodonite Pyroxmangite Ferrosilite III
Formula Al2SiO5 Al2SiO5 Al2SiO5 Al2SiO4(F,OH)2
Form.Wt.
Z
CrystalSystem
PointGroup
SpaceGroup
UnitCell
a(Å)
b(Å)
c(Å)
alpha
beta
gamma
Vol(Å3)
MolarVol
Density
Thermal Expansion(Volumetric)
alpha
a0
a1
a2
Elastic Properties
Ks(GPa)
G(Gpa)
Mineral Data Base Index