Neutronic missiles were weapons developed by several races.
Draconian battle cruisers were armed with neutronic missiles. A battle cruiser was sent to meet the humans to negotiate a peace treaty. Its missiles were unloaded to comply with the terms of negotiation. (TV: Frontier in Space)
The Thals developed neutronic missiles towards the end of their Thousand Year War with the Kaleds. The Thals placed all their remaining resources into the missile project in the hopes that would bring them victory in one decisive strike. Mutos from the wastelands, including Sevrin, as well as Sarah Jane Smith, whom Thal authorities mistook for a Muto, were used as slave labour to pack the rocket's nose cone with distronic explosives. Since no shielding was provided in order to reduce the weight of the missile, the slaves would contract distronic toxaemia and die after a few hours' exposure.
Davros, betraying the Kaleds, came to the Thal Dome and declared that he only desired peace. He informed the Thals that, if fired, the missiles would not destroy the Kaled Dome, but gave them a chemical formula which would weaken the Kaled Dome enough to destroy it. (TV: Genesis of the Daleks)