Transcript Lecture 02 Chem 1

Chemical Properties of Minerals I
Putting All Minerals in Perspective
Creating the molecules of life
C
H
Carbohydrates
and
Fats
N
O
Proteins
So, why do we need more?
S
P
Nucleic
Acids
But…will these six elements give us life?
Will they….
give us movement?
allow us to grow and develop?
generate energy?
maintain internal homeostasis?
build bones and teeth?
maintain fluid balance?
stimulate muscles to contract?
propagate nerve impulses?
determine the color of fur and skin?
optimize our immune system?
What chemical elements do we associate with life?
C
H
N
Na
K
Ca
Fe
Zn
V
Si
As
Ni
Cr
Sn
Cu
O
S
Mg
Cl
Mn
Mo
B?
P
Se
I
Co
Br
F
28?
Chemical Principles
Underlying the Properties
of Minerals
Noble Gases
Macrominerals
Non-metals
Microminerals
First transition series
3d
4d
5d
Iodine
(heaviest)
Properties of Minerals Relevant to
Function and Selection
5 major properties related to a particular mineral’s
function and selection
1. Charge or valance state of the ion
2. Solubility in water
3. Redox property
4. Coordination geometry
5. Choice of ligand
Valance State of Macro- and Microminerals
Macro
Sodium
Potassium
Magnesium
Calcium
Chlorine
Micro
Na+
K+
Mg2+
Ca2+
Cl-
Iron
Fe2+, Fe3+,Fe4+
Zinc
Zn2+
Copper
Cu+, Cu2+,Cu3+
Manganese Mn2+,Mn4+,Mn5+
Cobalt
Co+, Co2+, Co3+
Nickel
Ni+, Ni2+
Molybdenum Mo4+, Mo5+,Mo6+
Iodine
I-
Denotes most common oxidation states in solution at neutral pH
Solubility in Water
Rule: A mineral that is freely soluble in water
can easily move through extracellular and
intracellular fluids.
Rule: Paradoxically, charge on the molecule
is not the only determinant of water solubility,
atomic number must also be considered
Rule: Minerals capable of “hydrolyzing” water work
against solubility
Solubility varies with charge and atomic number
Ion/complex
Na+, K+
10-1 M
Macrominerals
Mg2+, Ca2+
10-3 M
Zn2+
10-9 M
Cu2+
10-12M
Fe3+
10-17M
pH 7.0 with chloride as counter ion
Microminerals
Metals as hydrolytic agents
Fe3+ + 3H2O
Fe(OH)3 + 3H+
Insoluble hydroxide
Cu2+ + 2H2O
Cu(OH)2 + 2H+
H+
Acid (low pH) favors solubility
Oxidation-Reduction (redox metals)
Rule: Metals with multiple valance states have the capacity
to take and give electrons, thereby acting as oxidizing and
reducing agents, respectively.
Corollary: Fixed valence metals cannot behave as
redox agents
Cu2+ + Fe2+
Cu+ + Fe3+
Copper is reduced, iron is oxidized
Copper is oxidized, iron is reduced
Zn2+ + Fe2+
No reaction
Coordination Complexes
Rule: Metal ions, especially micro- adhere to a strict
configuration in number of ligands and spatial
orientation when forming complexes
Rule: Adherence to coordination requirements has a
major impact on selection of a particular metal ion for
a function and rejection of others to replace the
selected one.
Rule: Metal ion antagonism and synergism is strongest
when two metals have the same coordination properties
3d10
3d9
Ion
Orbital Config Coordination No.
Cu+
(tetrahedral) d10
dsp3
4
Zn2+
(tetrahedral) d10
dsp3
4
Cd2+ (tetrahedral) d10
dsp3
4
Hg2+ (linear)
d10
dsp
2
Cu2+ (sq. plan)
d9
dsp2
4
Ag2+
(sq. plan)
d9
dsp2
4
Fe2+
(octahedral) d5
d2sp2
6