Fajan’s Rules « Aetus Designs

Fajan’s Rules

Fajan’s Rules are a set of empirical rules that are used to predict whether an inorganic compound will be ionic or covalent.

I find it easier to remember stuff when it look’s like math, so I organized these rules in the form of proportions. Hopefully, it will help others as well.

$\text{Cation Size} \varpropto \text{ Ionic nature }$
$\text{Anion Size} \varpropto \frac{1}{\text{ Ionic nature }}$
$\text{Charge on the cation or anion (or both)} \varpropto \frac{1}{\text{ Ionic nature }}$
$\text{Cation with inert gas configuration} \qquad \quad \ \rightarrow \ \text{Ionic Compound}$
$\text{Cation with pseudo-inert gas configuration} \rightarrow \ \text{Covalent Compound}$

Tags: fajan, inorganic chemistry

This entry was posted on Saturday, August 15th, 2009 at 3:26 pm and is filed under Chemistry, Science. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

Fajan’s Rules

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