|
|
MINERALS AND SYNTHETIC COMPOUNDS, AmXn, IN WHICH X
ATOMS ARE |
|
CLOSE PACKED AND A ATOMS OCCUPY OCTAHEDRAL INTERSTICES |
| |
|
. |
|
Rutile |
|
click here to see a key to this data bar
|
|
octa |
50% |
hcp |
3-d |
2
edges, 2 vertices |
A-
6c, X- 3c/hcp |
|
. |
|
structure |
. |
|
. |
. |
|
The rutile structure is
comprised of HCP packed X atoms with A atoms occupying |
. |
|
50% of the octahedral interstices of each
successive layer. |
. |
| |
. |
|
Ex. TiO2 ( titanium dioxide,
rutile ) ( Ti - A , O - X ) |
. |
|
. |
|
Crystal lattice |
|
The HCP lattice model
for rutile shows that the occupied AX6 groups in each layer |
|
are linked into continuous chains that are
separated by rows of unoccupied voids. |
|
Chains in successive layers are staggered
relative to each other so that they are |
|
linked by their vertices. |
| . |
|
|
|
| |
 |
|
|
Figure 86 -
Rutile lattice structure |
|
click image to enlarge |
|
| |
|
| |
| . |
|
|
|
|
|
Polyhedral framework |
| . |
|
|
|
|
linking surfaces |
 |
|
|
 |
Figure 87 -
Rutile polyhedral |
|
framework model |
|
( 86T, 116 pinges ) |
|
2
edges, 2 vertices |
click image to enlarge |
| . |
|
|
|
|
|
The occupied AX6
chains are clearly revealed in the polyhedral framework model |
|
as well as their linkage. |
|
. |
|
Cleavage |
Crystal habit |
|
(111) - perfect, (100) - good, (110) - good |
prismatic |
|
. |
|
|
|
Isostructural minerals/compounds |
|
MgF2, FeF2, CoF2,
NiF2, MnF2, ZnF2, GeO2 (low),
SnO2, PbO2, a-MnO2,
RuO2, IrO2, |
|
FeTa2O6, MgSb2O,
SiO2 (stishovite) |
|
. |
|
|
 |
Page
57 - Structure matters - Rutile |
 |
