What is the ruling on a marriage with a dowry, part of which is prompt and part deferred, not becoming due except upon death or separation?

Postponing the dowry is permissible if it is agreed upon. The wife or her family are not entitled to demand the deferred amount while the wife is under the husband's marital authority, nor is she entitled to refuse intimacy until she receives the deferred dowry. If she goes to her family and they prevent her from returning to him on the pretext that the dowry has not been paid, they have no right to do so, and the wife is considered disobedient (nashiz) and is not entitled to maintenance.