The crystal structures of three compounds derived from the reduction of Mn2(CO)10 with potassium in liquid ammonia solution with and without the presence of [2.2.2]crypt ([2.2.2]crypt = 4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo[8.8.8]-hexacosane) is reported. For the formation of [K([2.2.2]crypt)]2[HMn(CO)4] 2 NH3 and K3[Mn(CO)4] 2 NH3, liquid ammonia plays a crucial role as a solvent providing solvated electrons used for the reduction as well as for the stabilization of highly charged manganese carbonylates in ammoniate crystals. The isolation of [K([2.2.2]crypt)][Mn(CO)4(NH3)] 3 NH3 offers an insight into a possible intermediate during the reduction from [Mn(CO)5]− to [Mn(CO)4]3− via the ammonia alkali metal route.