( and ( ( ( ( ionic compounds ) , ) ( composed ( of ( ( ( cations ( of ( one substance ) ) ) and ) ( anions ( of another ) ) ) ) ) ) . ) )
(ROOT (FRAG (CC and) (NP (NP (JJ ionic) (NNS compounds)) (, ,) (VP (VBN composed) (PP (IN of) (NP (NP (NP (NNS cations)) (PP (IN of) (NP (CD one) (NN substance)))) (CC and) (NP (NP (NNS anions)) (PP (IN of) (NP (DT another)))))))) (. .)))
and ionic compounds, composed of cations of one substance and anions of another.
(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.