¡La Esquina de la Gramática! Rule 26
“Sino” and “si no”. There is a difference between them! The form “si no” (with a space in between) always introduces a conditional sentence. The word “si” is a conjunction (which introduces a conditional formula), and “no” is a negative adverb. Example: Si no hubiera intervenido el juez… The form “sino” (no space in between) is an adversative conjunction, which is mainly used to set against an affirmation to something previously denied: No fue expulsado (what is denied), sin