C208 Captain reported the aircraft tail contacted the ground due to an aft CG when the tug disconnected. Aircraft was restabilized and passengers deplaned.

Narrative

We began the boarding process for Aircraft X at roughly XA:20 at Gate X. The gate-agent presenting both the security form and the manifest for the flight. After looking over the manifest we both made a note that the CG was close to its aft limits but still within range. We both signed the manifest. The First Officer went down to the aircraft to do security check and preflight walk around. Afterwards; the passengers were let down the stairs from the gate to the ramp. First Officer boarded passengers in the order according to seat assignments. First Officer then secured the airplane door; chocks removed by the gate agent; and the First Officer removed the tail stand and secured pod C with chocks and tail stand inside. At this time the plane was in stable configuration. Captain did another scan and made sure everyone was in the correct seat assignments. Captain then requested pushback from Ramp. First Officer boarded the airplane and started the passenger brief. Captain signaled to the ramp agent to remove chocks and push. Captain released the parking brake and the airplane began to move. It was within a few moments; the nose smoothly climbed and the tail strike occurred. We signaled our ramp agents over to immediately discuss what had happened. The ramp agents informed us the tug was no longer attached to the nose gear and the tail was on the ground. The Captain notified Dispatch and Ramp. Station manager called Airport ops to come help get the tail off the ground. After the initial tail strike occurred passengers were briefed by the First Officer to remain in their seats with seatbelt fastened as we get the situation figured out. Passengers remained calm during the entire incident. The flight crew kept asking the passengers if they were okay or in need of any medical assistance. Passengers were in good spirits as they did not need any medical assistance or reported any injury. The fire department deployed an airbag under the tail to softly bring the nose back down. We briefed the passengers of the situation and requested they fasten their seatbelts for the nose coming back down. Once the nose of the aircraft was safely secured on the ground; the fire department notified the Captain that we could deplane the passengers. The First Officer got out and deplaned the passengers. Both Pilots complied into giving a statement and information to Airport Ops and Airport Police for their reports. No additional passenger comments or injuries.