Asteroid Spectroscopy

In minerals, the metal cations (e.g., Fe 2+ ) are
often surrounded by oxygen anions (O 2- )
A common structure
is 6 oxygen ions
surrounding 1 metal
ion (octahedral
coordination)
⇒ olivine, pyroxene
In such a site, the “on-axis” d X
2 -Y
2 and d Z
2 are closer to
the oxygen anions than the three “between the axes”
orbitals (d xy , d xz , d yz ).