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1 – Description of ionic crystals
It is interesting to consider a simplified version of this relation: [D ′ M ] = [V
•
X ].
The doping causes an increase in the size of the domain where ionic defects
dominate and, consequently, of the electrolytic domain of the crystal.
1.4 – Stoichiometry and departure from stoichiometry
A crystal described by the formula M a X b is stoichiometric if the following
condition is satisfied:
Number of X atoms
Number of M atoms b
a
=
Otherwise, the compound is said to be non-stoichiometric or to depart by δ from
stoichiometry (see glossary). This departure is due to the physical-chemistry
conditions imposed on the crystal (temperature, P X 2 , ...). For example, for the
compound MX 2 shown in figure 2, the stoichiometry is represented by the
point S , which is characterized by the partial pressure P X 2 ,S and the temperature
T S = T to which the diagram corresponds.
1 – Description of ionic crystals
It is interesting to consider a simplified version of this relation: [D ′ M ] = [V
•
X ].
The doping causes an increase in the size of the domain where ionic defects
dominate and, consequently, of the electrolytic domain of the crystal.
1.4 – Stoichiometry and departure from stoichiometry
A crystal described by the formula M a X b is stoichiometric if the following
condition is satisfied:
Number of X atoms
Number of M atoms b
a
=
Otherwise, the compound is said to be non-stoichiometric or to depart by δ from
stoichiometry (see glossary). This departure is due to the physical-chemistry
conditions imposed on the crystal (temperature, P X 2 , ...). For example, for the
compound MX 2 shown in figure 2, the stoichiometry is represented by the
point S , which is characterized by the partial pressure P X 2 ,S and the temperature
T S = T to which the diagram corresponds.