From him, from Safwan ibn Yahya, from Isma'il ibn Jabir, from Abu Abdillah عليه السلام, peace be upon him::
I asked Him عليه السلام about the time of Maghrib. Imam عليه السلام said: "It is from the setting of the sun until the disappearance of the twilight."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 276