Question

Can metals-metals have a covalent bond

Answer 1

Yes. Metallic bonds exist in metal crystal lattices. But in other compounds containing a rwo or a few metal atoms, they can be covalently bonded.

Mercury (I) Chloride, formerly written as HgCl, was actually proven to be Hg2Cl2, with the two Hg atoms covalently bonded. [Hg-Hg]Cl2 is a more proper representation of the compound.

Rhenium (IV) Chloride exists as Re2Cl8 not ReCl4. It contains a triple covalent bond, having this structure: Cl4Re:::ReCl4

Alkali metals in their gaseois state exist as diatomic molecules, having a single covalent bond like Hydrogen. Na-Na and K-K are examples.

Many organometallic compounds have 3 or 4 metal atoms, sometimes different, bonded as a cluster at the center.