I usually use the possessives mi and mío interchangeably. For example: Esta es la casa mía. Esta es mi casa. However, do the two have different connotations? (e.g. is one more formal ...
In Spanish there are some adverbs followed by de: Delante de, atrás de, en frente de, etc... When these adverbs are followed in a sentence by a declined pronoun, they are often "contracted" ...