( ( Metallic bonding ) ( ( refers ( to ( ( the ( specific bonding ) ) ( between ( ( ( positive ( metal ions ) ) and ) ( surrounding ( valence ( electron clouds ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Metallic) (NNP bonding)) (VP (VBZ refers) (PP (TO to) (NP (NP (DT the) (JJ specific) (NN bonding)) (PP (IN between) (NP (NP (JJ positive) (NN metal) (NNS ions)) (CC and) (NP (VBG surrounding) (NN valence) (NN electron) (NNS clouds))))))) (. .)))
Metallic bonding refers to the specific bonding between positive metal ions and surrounding valence electron clouds.
(ROOT (S (NP (DT A) (JJ metallic) (NN bond)) (VP (VBZ is) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NP (NN attraction)) (PP (IN between) (NP (NP (DT a) (JJ positive) (NN metal) (NN ion)) (CC and) (NP (JJ valence) (NNS electrons)))))))) (. .)))