Who are those behind whom it is not permissible to pray – may Allah reward you with goodness?

It is not permissible to pray behind a disbeliever, or behind one who holds an apostatizing innovation, or one who is not purified from ritual impurity or defilement, or one who is not of sound mind (such as a drunkard or an insane person), or one who is unable to perform a pillar of prayer for those who are able to do so, or one who cannot recite Al-Fatiha despite being able to learn it, or a mute person for those who can speak. Nor is it valid for a woman to lead men in prayer, nor for a congregant to lead others while he himself is being led.