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Both bonds result in forming of differentiating properties and structures. Atoms react in order to achieve stability.

However, covalent bonds have a unique property that ionic bonds do not have, and that is occurrence.

Unlike ionic bonds that only react between a metal (cation) and a non-metal (anion), covalent bonds are strictly non-metals and non-metals.

Ionic bonds involve the cation "donating" their to the anion, resulting a strong chemical bond. This leads to many different, beneficial properties.

Covalent bonds share electrons, forming pairs with other atoms. This can lead to complex molecules such as glucose, $C_"6"H_"12"O_"6"$.

Additionally, the sharing of electrons is very weak compared to the those in an ionic bond. also have a property of being polar and non-polar, something don't have.

There are a lot more, but I've went through the basics.

Hope this helps :)