De for of
What situations would you use the preposition de for of, instead of the genitive case?
Either de or the genitive could be used for a material or an instrument (i.e. cause), e.g. bróg adhmaid or bróg d’adhmad, buille cloig or buille de chlog.
One would need to use de in a partitive noun phrase with an indefinite governing noun and a definite governed noun, e.g. leithreas den teach (“a toilet of the house”) vs. leithreas an tí (“the toilet of the house”).