( ( Each ( of ( these ( ionic compounds ) ) ) ) ( ( contains ( ( ( one cation ) and ) ( one anion ) ) ) . ) )
(ROOT (S (NP (NP (DT Each)) (PP (IN of) (NP (DT these) (JJ ionic) (NNS compounds)))) (VP (VBZ contains) (NP (NP (CD one) (NN cation)) (CC and) (NP (CD one) (NN anion)))) (. .)))
Each of these ionic compounds contains one cation and one anion.
(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.