Geology Reference
In-Depth Information
Group
Element
Oxidation states
01
la
Potassium
K
Ca
0
lla
Calcium
2
0
3
llla
Scandium
Sc
0
2
3
4
lVa
Titanium
Ti
*
0
Va
Vanadium
V
2
3
45
*
0
2
3
6
Vla
Chromium
Cr
*
0
2
3
4
6
7
Vlla
Manganese
Mn
Iron
Fe
0
2
3
4
6
Vll
Co
Cobalt
0
2
3
4
Nickel
Ni
0
2
34
lb
Copper
Cu
0
12
3
llb
Zinc
Zn
0
2
0
lllb
Gallium
Ga
3
Oxidation state
found in geological
environments and meteorites
Other oxidation
states stable under
laboratory conditions
*
Oxidising agents
Figure 9.8
Oxidation states of the first transition series.
(c) Transition metals form a wide range of co-ordin-
ation
complexes,
some of which play an important
part in stabilizing the metals in solution and pro-
moting their transport in hydrothermal fluids (e.g.
equations 4.31 and 4.32; Box 7.5).
(d) Transition-metal compounds are often strongly
coloured
(Box 9.10). Many minerals owe their dis-
tinctive colours to the presence of a transition
metal.
(e) Transition metals are responsible for the
magnet-
ism
of minerals and rocks. This property, most
prominent in the later members of the first trans-
ition series (Fe, Co, Ni), is due to the presence of
unpaired electrons
in the d subshell. Unlike valence
electrons, these 3d electrons may remain unpaired
when the metal atom combines in a compound.
Paired electrons in an orbital generate equal and
opposite magnetic fields which cancel out, but an
unpaired electron causes a net magnetic field,
which in the case of a few minerals like magnetite
and pyrrhotite gives rise to permanent (remanent)
magnetism.
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