家 vs 家庭（近义词）

1)Both words mean family:
2)家庭，which is relatively formal,is not suitable in example②.
3)家 can also mean"address,residence":
4)家 sometimes is used figuratively,e.g.职工之家(Workers'Home,a place for recreational activities )In examples③④⑤，家庭 is not used, but when the address is referred specifically as when filling in a form),it is used,such as家庭地址.There are also some customary collocations,e.g.家庭关系(relationship between family members),家庭作业(homework),和睦家庭(harmonious family),etc.
5)家 is also a measure word for household,store,factory,etc.e.g.住着两家人(Here live two families),一家饭馆(a restaurant),一家商店(a store),两家工厂(two factories),etc.
6)家 is also a suffix,meaning "a specialist",e.g.作家(writer),科学家(scientist),画家(painter),探险家(explorer),etc.