( ( ( hydrogen bond ) ( ( ( A ( weak ( electrostatic attraction ) ) ) ( between one ) ) ( electronegative ( ( ( atom ( -LRB- ( ( ( ( biochemically oxygen ) or ) nitrogen ) -RRB- ) ) ) and ) ( a ( hydrogen atom ) ) ) ) ) ) ( covalently ( ( linked ( to ( a ( second ( oxygen ( or ( nitrogen atom ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (NP (NN hydrogen) (NN bond)) (SBAR (S (NP (NP (DT A) (JJ weak) (JJ electrostatic) (NN attraction)) (PP (IN between) (NP (CD one)))) (VP (VBP electronegative) (NP (NP (NN atom)) (PRN (-LRB- -LRB-) (NP (NP (JJ biochemically) (NN oxygen)) (CC or) (NP (NN nitrogen))) (-RRB- -RRB-)) (CC and) (NP (DT a) (NN hydrogen) (NN atom))))))) (ADVP (RB covalently)) (VP (VBN linked) (PP (TO to) (NP (DT a) (JJ second) (NN oxygen) (CC or) (NN nitrogen) (NN atom)))) (. .)))
hydrogen bond A weak electrostatic attraction between one electronegative atom (biochemically oxygen or nitrogen) and a hydrogen atom covalently linked to a second oxygen or nitrogen atom.
(ROOT (S (NP (NNP Oxygen)) (VP (VBZ is) (NP (NP (DT the) (NN name)) (PP (IN of) (NP (DT the) (JJ second) (ADJP (RBS most) (JJ electronegative)) (NN element))))) (. .)))