How to recognize the covalent properties of some ionic compounds
How to recognize the covalent properties of some ionic compounds
FeCl3 Tri-Iron Compound and FeCl2 Di-Iron Compound
Al2O3 aluminum oxide and AlCl3 aluminum chloride
HCl or H2O
MgCl2 or NaCl
AlF or Al2O3
Those who are interested in chemistry meet some of the compounds that appear to them to be ionic compounds at first sight, given that the two main elements are a metallic element and another that is not metallic, regardless of the difference
It may not be the judge in judging the properties of some of the compounds in that they are compounds with covalent properties or not
Let me give you some examples
FeCl3, FeCl2, and FeCl2. Both components are iron and chlorine. On the surface, the compound may look ionic, but after observing some of the rules that we will mention, our concept of the properties of the compounds will change completely.
First: The positive ion charge must be considered when comparing the properties of the two compounds. The higher the charge, the more the characteristics of the covalent compound appear in the compound. According to that clause, you can now judge which covalent characteristic appears because both elements are involved in chlorine.
The triple iron chloride compound according to the first item is more covalent than the di-iron chloride
Second: Let me mention another example for you, let there be Al2O3 aluminum oxide and AlCl3 aluminum chloride that the common factor in both compounds is aluminum so we will not talk about the positive ion charge but rather we will mention the second item
Second: The size of the negative ion increases: - The greater the negative ion size, the more the appearance of covalent compounds. Therefore, in the previous example we know the size of the chlorine atom greater than the size of the oxygen atom. Therefore, the characteristic of the covalent compound appears in the compound AlCl3 than in the compound Al2O3.
This matter gives us an explanation for the many covalent compounds of some of the compounds, despite being ostensible
As a matter of training, all you need now is to apply the same principle to the following vehicles on your own
Either the covalent compound has the largest HCl or H2O compound
The answer "Compare the size of the chlorine atom to the size of the oxygen atom, because the two compounds in the hydrogen atom are similar to each other, so HCl is more covalent.
Another example: Which is more covalent, MgCl2 or NaCl
Answer: Look at the positive ion charge, for the similarity of chlorine in both compounds
The compound MgCL2 is the largest covalent of the large magnesium ion charge, two
And so on
Training questions which are more covalent to AlF or Al2O3
The answer is undoubtedly AL2O3 because the volume of negative oxygen is greater than the negative fluorine ion
With my regards, Atef Abu Al-Saud, Director of Chemistry of Kafr El-Sheikh
