Anion Bridge Bonding
Bridging bonds occur when a mono-valent hydride or halogen anion is held between a pair of Lobe-LUMO Lewis acid centres.

The classic example of the bridging bond is found in diborane, B2H6.

Bridging bonds are most commonly found in simple inorganic hydrides and halides, such as PdCl2.

For more information look in the Chemogenesis webbook sections on Lewis acids and Lewis bases and the Lewis acid/base interaction matrix.