Coordinate Covalent Bonds

[Luis Torres 1C]

I know we've somewhat gone over this in class, but could someone explain what exactly is a coordinate covalent bond?

[kendallbottrell]

Coordinate covalent bonds are where both of the electrons that form the bond originate from the same atom.

[Steven Luong 1E]

A coordinate bond (also called a dative covalent bond) is a covalent bond (a shared pair of electrons) in which BOTH electrons in one of the shared bonds come from the same atom.

[Sarai Ventura 1L]

A covalent chemical bond between two atoms that is produced when one atom shares a pair of electrons with another atom that lacks such a pair. Also known as a covalent bond in which both the shared electrons are contributed by one of the two atoms.

[Sophia Diaz - Dis 1B]

How exactly would these bonds happen though? If they both come from the same atom wouldn't that atom want to hold onto the electrons as much as possible? Does it have something to do with periodic trends?