Answer:
Tartarus was the Greek and Roman mythology was the equal to Hell. Though all deceased souls passed through the underworld, only the sinners ect. were went to Tartarus, where they would suffer and be tormented for all eternity. There was also an opposite of Tartarus, where good souls and heroes would go after they finally died and that was known by any names, so it is referred to as simply 'paradise'.
So yes Tartarus was an evil place, for the world's evilest souls.
Sorry but I thought that when souls died, they went to Underworld. There, the heroes went to Elysium, those who were nor good nor bad went to the Fields of Asphodel, and those who were bad went to the fields of punishment. Tartarus would be the pit where the gods imprisioned the Titans.