( Cations ( ( ( are also ) ( ( a part ) ( of ( certain ( organic compounds ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Cations)) (VP (VBP are) (ADVP (RB also)) (NP (NP (DT a) (NN part)) (PP (IN of) (NP (JJ certain) (JJ organic) (NNS compounds))))) (. .)))
Cations are also a part of certain organic compounds.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (VP (VBG naming) (NP (DT an) (JJ ionic) (NN compound))))) (, ,) (NP (DT the) (NN cation)) (VP (VBZ is) (VP (VBN written) (ADVP (RB first)))) (. .)))
When naming an ionic compound, the cation is written first.