The Student Room Group

Which is stronger- covalent or ionic bonds???

In chemistry, we've learnt that ionic bonds are stronger than covalent.
In biology, we've learnt that covalent bonds are stronger than ionic.

????

OR why is there this difference?
covalent bonds are stronger

There are strong covalent bonds between the atoms, but weak inter molecular forces between the molecules
(edited 4 years ago)
There are a number of things to consider when thinking about this:1. Ionic bonds are generally strong due to the attraction of oppositely charged ions. Covalent bonds are also strong due to the attraction from each nuclei to the valence electrons.2. However the intermolecular bonds in most covalent compounds are very weak, they often only have instantaneous-induced dipole bonding, so will exist as gases at room temp.3. Ionic compounds exist in giant lattice structures rather than diatomic molecules so will exist as solids with high melting points.4. However some covalent compounds can exist as a giant covalent network, such as in diamond. This is where all carbon atoms are bonded to 4 other carbon atoms and this makes a very strong compound with extremely high melting points.However, in terms of the pure strength of the intra-molecular bonds (between atoms in a molecule), covalent bonds are stronger.
Reply 3
Original post by poiuytewq
There are a number of things to consider when thinking about this:1. Ionic bonds are generally strong due to the attraction of oppositely charged ions. Covalent bonds are also strong due to the attraction from each nuclei to the valence electrons.2. However the intermolecular bonds in most covalent compounds are very weak, they often only have instantaneous-induced dipole bonding, so will exist as gases at room temp.3. Ionic compounds exist in giant lattice structures rather than diatomic molecules so will exist as solids with high melting points.4. However some covalent compounds can exist as a giant covalent network, such as in diamond. This is where all carbon atoms are bonded to 4 other carbon atoms and this makes a very strong compound with extremely high melting points.However, in terms of the pure strength of the intra-molecular bonds (between atoms in a molecule), covalent bonds are stronger.

How though? Surely ionic are as they have a full positive and negative charge whereas in covalent bonding, the atoms would have a slightly positive and slightly negative charge??
Reply 4
Maybe covalen to but I'm not sure . I think the statement about strength of a bond is very unscientific without knowing strength under what circumstances

If water is boiled in a kettle, hydrogen bonds are broken but covalent bonds are not broken.
So people talking about intermolecular bonds eg between H2O molecules are bringing up completely irrelevant things.

If I take a hammer against a solid ionic compound like sodium chloride Vs a covalent one like diamond. I would break sodium chloride much easier. So if the test is a hammer then I suppose covalent is stronger

Also re temperature I think covalent is stronger. Like breaking water molecules internally might in the thousands of degrees C

added-
I just heard an interesting thing that might answer your question re a discrepancy you heard. Your biology text/class might have said that covalent is stronger,because biochemistry involves water a lot and ionic bonds break easily in water.
(edited 1 year ago)

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