Yes, a free neutron decays to a proton, an electron and an electron neutrino with a half life of 879 seconds. This decay releases 0.8MeV of energy (mostly in the form of kinetic energy of the electron).
My back of the envelope calculation shows that 1 gram of neutronium (approximately a mole) will release 43MW of energy continuously. Multiply that by 10^14 (the number of grams of neutronium per teaspoon) and the resultant energy release would be unimaginably huge. 'Explosively' does not even begin to describe it.
My back of the envelope calculation shows that 1 gram of neutronium (approximately a mole) will release 43MW of energy continuously. Multiply that by 10^14 (the number of grams of neutronium per teaspoon) and the resultant energy release would be unimaginably huge. 'Explosively' does not even begin to describe it.