SODIUM AND POTASSIUM AMIDOMETALLATES OF CALCIUM, STRONTIUM AND EUROPIUM

The systems Na/M/NH3 with M = Ca, Sr, Eu, and K/Sr/NH3 were investigated. Under the conditions of the ammonothermal synthesis at temperatures between 570 and 670 K and pressures of 5000 bar, the following ternary amides -besides the binary compounds -can be prepared: NaCa(NH2)3, KSr(NH2)3, Na2Sr3(NH2)8, and Na2Eu3(NH2)8. (For the crystal data see Zusammenfassung.) In the four compounds the anions are in a distorted cubic closepacking. The cations are in octahedral interstices with partially statistical occupancy. The crystal chemistry of the compounds is compared with such related amidometallates as KEu(NH2)3 and Na3La(NH2)6. The thermal degradation of the ternary alkaline earth metal amides leads to the imides together with undecomposed alkali metal amide. The europium compound gives EuN directly with additional evolution of hydrogen. © 1979.