What is the ruling of Islamic law concerning throwing a copy of the Qur’an and a religious book at one's wife with the intention of harming her, and is repentance from this grave sin accepted?

Discarding and throwing the Mushaf (copy of the Qur'an) contradicts its reverence. If it is done out of contempt, then it is an act of disbelief (kufr).

However, no matter how great the sin, Allah accepts sincere repentance and rejoices in it, forgiving all sins, as He Almighty says: "Say, "O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful."" (Qur'an 39:53)

Therefore, it is obligatory to hasten to repentance by abandoning the sin, regretting it, and resolving not to return to it. One must also strive to control oneself when angry, for the strong person is he who controls himself when angry. The Prophet, peace and blessings be upon him, advised against anger.