( ( A ( triple bond ) ) ( ( consists ( of ( ( ( three ( shared ( electron pairs ) ) ) , ) ( forming ( ( ( one sigma ) and ) ( two ( pi bonds ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ triple) (NN bond)) (VP (VBZ consists) (PP (IN of) (NP (NP (CD three) (VBN shared) (NN electron) (NNS pairs)) (, ,) (VP (VBG forming) (NP (NP (CD one) (NN sigma)) (CC and) (NP (CD two) (NN pi) (NNS bonds))))))) (. .)))
A triple bond consists of three shared electron pairs, forming one sigma and two pi bonds.
(ROOT (S (PP (IN In) (NP (DT a) (NN carbon) (JJ triple) (NN bond))) (, ,) (NP (NP (CD three) (NNS pairs)) (PP (IN of) (NP (NNS electrons)))) (VP (VBP are) (VP (VBN shared))) (. .)))