LiCa 3 Si 2 N 5 – A Lithium Nitridosilicate with a [Si 2 N 5 ] 7– Double‐Chain

The lithium nitridosilicate LiCa 3 Si 2 N 5 was synthesized by the reaction of calcium with Si(NH) 2 and Li 3 N in weld shut tantalum ampoules at 900 °C. The structure of LiCa 3 Si 2 N 5 [space group C 2/ c , no. 15, a = 5.1454(10), b = 20.380(4), c = 10.357(2) Å, β = 91.24(3)°, wR 2 = 0.1084, 863 data, 102 parameters] consists of [Si 2 N 5 ] 7– double‐chains including edge‐sharing tetrahedra. The lithium atoms in the crystal structure are situated in strands along the crystallographic b axis. Lattice energy calculations (MAPLE) and EDX measurements confirmed the electrostatic bonding interactions and the chemical composition. The 29 Si and 7 Li solid‐state MAS NMR spectroscopic investigations are reported.