Aluminum chloride is composed of aluminum and chloride likewise known as aluminum trichloride or aluminum (III) chloride having the chemical formula AlCl3. It shows up as white to grey powder through a pungent odor. In equipment forms, it shows up as a straw-colored liquid. That is mainly used in the manufacturing of aluminum metals.

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In this article, us will talk about Is Aluminum chloride (AlCl3) is ionic or covalent? Bond species in aluminum chloride, etc.

So, Is AlCl3 ionic or covalent? AlCl3 is a covalent compound together the shortcut formed between one aluminum and three chlorine atom through the shared sharing the electrons because of the polarization power effect(Based on Fajan’s rule). Also, the distinction in electronegativity value between aluminum and also a chlorine atom is not huge enough to do the ionic bond in between them according to the Pauling scale.

Although, AlCl3 is not purely covalent in nature, there is a partial ionic character together well.

Let’s check out in detail, why AlCl3 is a covalent compound? exactly how covalent bonds formation takes place in AlCl3?

Name of MoleculeAluminium chloride
Chemical formulaAlCl3
Molar mass133.34 g/mol
Bond typeCovalent
Percentage character55% covalent and also 45% ionic character

Page Contents show
1 Why AlCl3 is one covalent compound?
2 how covalent bond is formed in AlCl3?
3 Why is AlCl3 not a ionic compound?
4 Is AlCl3 pure covalent compound?
5 room the bonds in AlCl3 polar covalent or nonpolar covalent?
6 properties of aluminum chloride
8 summary

Why AlCl3 is one covalent compound?

A covalent link is a chemical compound that is made once two nonmetals or 2 p-block elements together share your valence electron through each other to finish the octet and also attains stability.

Examples of part compounds that form covalent binding – H2O, H2S, NH3, NO2, SO2, etc.

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Note: It is not necessary constantly that a covalent shortcut will form between 2 nonmetals, it can additionally be formed when one atom is metal and also another is a nonmetal.

AlCl3 is a covalent compound since aluminum and also three chlorine atom are linked through the share of electrons with each other, although, aluminum is a metal and chlorine is a nonmetal, still, there does not take place a complete transfer that electrons in between the metal and also the non-metal. This deserve to be finest explained by the Fajans‘ rule.

Fajan rule’s are used to predict whether a chemical bond will be covalent or ionic, and also depend ~ above the fee on the cation and the relative sizes that the cation and anion.

Based on the Fajan rule, the ionic or covalent compounds have the right to be distinguished by the adhering to characteristics.

Ionic characteristicsCovalent characteristics
Small anionLarge anion
Low chargeHigh charge
Large cationSmall cation

Point to remember while utilizing the Fajans‘ rule come predict the covalent or ionic character:

The Fajans’ rule states that a compound through a large anion, big charge, and small cation will take on the covalent personality whereas a compound through a little anion, tiny charge, and huge cation will adopt an ionic character.Fajans’ dominion depends top top the size of the family member size that cation and anion for predicting the ionic or covalent character in the molecule.The smaller the dimension of the cation and the larger the size of the anion, the greater is the covalent character in the molecule.

Most important: The cation through a high hopeful charge will attract the electron in the outermost covering of the anion in the direction of itself such the the electron cloud the the anion is distorted, hence, the electron is attracted into the room between optimistic cation and an adverse anion, and also these electrons get shared between cation and anion. Therefore, the compound exhibit a covalent character.


Now, we will shot to understand Why AlCl3 has a covalent character according to the Fajans’ rule.

AlCl3 has actually two ions, Al3+ as cation and Cl– together the anion. The Al3+ is very tiny and highly charged, therefore, has a high charge density. The Cl– is a very huge anion compared to Al3+ and also has a an extremely low charge density.Al3+ has actually a very high polarizing power because it is extremely charged, so, once it comes close to the Cl–, climate it polarizes the electron cloud of Cl– come the huge extent.After polarizing the electron cloud the Cl– by the Al3+, the symmetrical form of the Cl– anion acquire distorted and electrons are drawn into the space between Al3+ and Cl–.The electrons that are drawn into the space between cation(Al3+) and also anion(Cl–) are gets shared to complete their octet, hence, the link formed in between the ions of AlCl3 is exhibited good covalent character.

In short, “Al3+ is very charged in nature and also it deserve to polarise the electron clouds the Cl– to a large extent. So, electrons get shared between the two ions. Hence the AlCl3 compound is a covalent one”


Although, the AlCl3 is developed from metal and also nonmetal and many of you assumed that it is an ionic compound yet the bond formation in these varieties of link such together AlCl3, AlF3, AlBr, and so on are ideal explained by the Fajans’ rule.

Ionic character in the covalent compounds and also covalent character in one ionic compound can quickly be predicted by the Fajans’ rule.

The covalent shortcut is created in AlCl3 due to the fact that each chlorine atom gets 1 electron native the Al atom v the sharing and attains stability.

Let’s see exactly how covalent bond development takes place in AlCl3.

There room two species of atoms existing in the AlCl3 molecule – aluminum and also chlorine atom.

⇒ The aluminum atom is a metal that belongs to group 3 in the periodic table and also has three valence electrons in the outermost shell.


⇒ The chlorine atom is also a nonmetal the belongs to group 7 in the regular table and has a 7 valence electron in that outermost shell.


So, when the cation(Al3+) and also anion(Cl–) the the AlCl3 compound come closer to each other, the cation(Al3+) polarize the electron cloud that the anion(Cl–), hence, the form of the anion obtain distorted and electron is shared in between these ions, and also a covalent shortcut is developed in AlCl3 compound.


As we see in the above snapshot of covalent bond formation in AlCl3, the chlorine atom has 7 valence electron in that outermost shell and it needs 1 much more to finish the octet, hence, each chlorine atom gets 1 electron native the Al atom with the sharing and attains stability

Note: an aluminum atom in the AlCl3 link attains stability by just having actually 6 valence electrons about it since it is superior to the octet rule.

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AlCl3 molecule has an ext covalent character than the ionic personality hence, it is said that AlCl3 is a covalent compound rather of ionic.

According to the Pauling scale, the AlCl3 molecule is no an ionic compound due to the fact that the difference in electronegativity value in between aluminum and a chlorine atom is not big enough to do an ionic bond in between them.

According come the Pauling scale of electronegativity-

The covalent bond is formed between the 2 atoms when their electronegativity difference occurs less 보다 1.7.The ionic shortcut is formed in between the two atoms once their electronegativity distinction occurs more 보다 1.7.


Now examine the electronegativity distinction in AlCl3 molecule-

⇒ The electronegativity value for aluminum atom = 1.61

⇒ The electronegativity worth for chlorine atom = 3.16

∴ The difference of the electronegativity between aluminum and also chlorine atom = 1.55

So, the difference in electronegativity in the Al-Cl link is much less than 1.7, hence, the is low enough to make a covalent bond between them together per the Pauling range of electronegativity.


∴ AlCl3 compound has actually three single covalent bonds(Al-Cl) as presented in that is lewis structure.

Also, check – just how to attract the lewis framework of AlCl3?

A pure covalent bond is mostly developed in the molecule have has actually the same form of atoms and also the same electronegativity, for instance – O2, F2, Cl2, etc.

Basically, a homonuclear molecule has the capacity to form a pure covalent bond because the electronegativity of atom is the same, hence, sharing of electron is also equal in them.

In short, a pure covalent shortcut is formed between the atoms when they share an equal variety of electrons.

So, Is AlCl3 a pure covalent compound? No, AlCl3 is a no pure covalent compound due to the fact that it is a heteronuclear molecule that consists of different types of atom (aluminum and also chlorine atom), and their electronegativity is additionally not the same.

The electronegativity because that aluminum is 1.61 whereas, for chlorine, it is 3.16. So, the electron are much more shared in the direction of the chlorine atom as it is higher electronegative 보다 the aluminum atom, hence, unequal sharing of electron occurs between aluminum and chlorine atoms.

So, the bonds formed in the AlCl3 molecule room not a pure covalent bond, hence, AlCl3 is not a pure covalent compound.


A polar covalent bond is created when the unequal sharing of electrons occurs between two atoms because of their distinction in electronegativity value.

When the difference of electronegativity occurs in between two atom lies in between 0.4 to 1.7, climate the link formed between two atoms is polar in nature follow to the Pauling range of electronegativity.


A nonpolar covalent shortcut is formed when the equal sharing of electron occurs between two atoms due to the fact that of the very small difference in their electronegativity value.

When the difference of electronegativity occurs between two atoms is less 보다 0.4, climate the shortcut formed in between two atoms is nonpolar in nature follow to the Pauling range of electronegativity.


So, Are the bonds in AlCl3 polar covalent or nonpolar covalent? The Al-Cl bond in the AlCl3 molecule is a polar covalent since the electronegativity difference in between aluminum and a chlorine atom is 1.55 which is in the selection of the Pauling range of the polar covalent bond native 0.4 to 1.7.

Also, the unequal share of electrons wake up in AlCl3 molecules because chlorine(3.16) is greater electronegative 보다 an aluminum atom(1.61), hence, it will certainly pull an ext electrons in the direction of itself, therefore, the chlorine atom induced a negative charge top top it and also aluminum atoms gain a slightly positive charge.

The separation of charges generates the dipole moment directed from confident to negative, hence, due to all this a link is formed between aluminum and also chlorine, i m sorry is dubbed a polar bond.


Properties that aluminum chloride

It has a molar fixed of 133.341 g/mol.It appears as white or pale yellow solid.It has a melting suggest of 180 °C.It has actually a low melting and boiling point.It is non-flammable and an effective lewis acid.It has a coordinate geometry that octahedral in the heavy phase and also tetrahedral in the fluid phase.


Why is AlCl3 covalent when AlF3 is ionic?

As Fajans‘ rule said, the covalent character boost when the size of the cation is little and the dimension of the anion large, therefore that, the anion quickly gets polarized by the cation, and also electrons gain shared between them.

So, in the situation of AlCl3 and also AlF3, the cation(Al3+) is the exact same for both compounds, hence, just neglect it. Now see the size of the anion of both compounds.

Clearly, Size of Cl– > dimension of F–

Hence, chlorine gets quickly polarised by the Al3+ however on the various other hand, the fluorine size is so small that Al3+ is not able come polarize the to together a great extent.

Therefore, we deserve to say, because of the size distinction of anion, the AlCl3 is covalent if AlF3 is ionic.

Why AlCl3 is covalent and not an ionic compound?

If you only see that AlCl3 is consisted of of one metal and nonmetal, then you could assume it as an ionic compound, and also here’s what friend get totally wrong.

AlCl3 has a predominately covalent character as described by the Fajans‘ rule. Return the AlCl3 compound is not purely covalent, it has part ionic character as well but that is predominately by the covalent character.

The AlCl3 bonds have actually 55% covalent character and 45% ionic character, hence, it is categorized together a covalent compound instead of the ionic compound.

Here, girlfriend can uncover the ionic percentage character of any type of compound by simply placing the electronegativity that atoms.

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Is Aluminum chloride (AlCl3) ionic or covalent? AlCl3 (aluminum chloride) is a covalent compound due to the fact that cation(Al3+) is extremely charged and able come polarize the electron cloud of the anion(Cl–) conveniently to the large extent, this phenomenon has attracted the electrons right into the room between the hopeful and negative ion and also here, this electrons get shared, and makes the covalent bond.AlCl3 bonds have actually 55% covalent character and also 45% ionic character, hence, the is not a pure covalent compound, the exhibits some ionic character together well.The distinction in electronegativity in between aluminum (1.61) and also chlorine(3.16) is 3.16–1.61 = 1.55 i beg your pardon is reduced than 1.7, hence, according to the Pauling scale, the shortcut formed between aluminum and also a chlorine atom is covalent in nature.There room three Al-Cl covalent bonds existing in the AlCl3 molecule.