This contracted form is seen chiefly in informal writing. Otherwise the full form zijn is written out even though the pronunciation is that of z’n.
However, the spelling z’n is used in formal writing in a few fixed expressions, such as met z’ndrieën (“involving a group of three people”), or op z’n hoogst (“at most”). In these phrases, z’n does not have the meaning of an actual possessive adjective.
1) Not as common in written language. 2) Inflected as an adjective.
3) In prescriptivist use, used only as direct object (accusative). 4) In prescriptivist use, used only as indirect object (dative). 5)Archaic. Nowadays used for formal, literary or poetic purposes, and in fixed expressions.