Is covalent bond = ionic bond

Don't just learn what they are. Think what they are. And also think WHY they are.

In some strict sense he's not completely wrong: all ionic bonds bear some extent of covalent character, large or small; Of course Ionic bond still is Not EQUAL to covalent bond.
May I explain later.

2012-08-25 11:53:50 補充：
In principle, there's no pure ionic bond, but there's pure covalent bond.

In a covalent bond, (most often) a pair of electrons are shared between two atoms.
If there's no difference in electronegativity (EN) between two atoms, then the electrons should be at middle of two atoms, forming a "pure" covalent bond.

If there' some difference in EN, electrons will be drawn toward one of the atoms. The covalent bond are said to be "polarized".

If the difference in EN is very large, electrons will be in effect drawn very close to one of the atoms, so that that atom will bear the electrons. This would be ionic bond.

But even if the difference in EN is large, electrons are not completely drawn to the "anion"; there's still some distortion to the electron cloud of the anion. That's your argument, right?


Strictly speaking, your argument makes some sense.
However, scientists don't make things to bug themselves. There're practical reasons to make such definition.

The properties of covalent bonds and "ionic bonds" could be very different, that we need to distinguish them and discuss separately. (Without considering the borderline cases,) such discussions are already effective to describe the nature of the bonds.

If such approach is sufficient to make things clear, why bother complicating them?

Yes, you're alert to details, and that's good; we just need something more simple (and equally good).

I like 己式庚辛's opinion.

Don't think what they are. Learn what they are.

First, for the ionic bond, in order to attain a stable configuration ( obey octet rule,the outermost electron is 2 or 8), different atom will lose or gain electrons from others to achieve this aim. That means for the ionic bond, it only involve in the gaining and losing of the electrons and this lead to the formation of the anions ( after losing electrons) and cations ( gaining electrons). As a result, the ionic bond is the directional electrostatic force between the positive cations and the negative anions.
Second, for the covalent bond, in order to obey octet rule, the atom will share their electrons in order to ensure the outermost electron is eight. The covalent bond is the non-directional attraction force between the atom.
It is meaingless to think in deep where is the electrons located.