LiLa 5 Si 4 N 10 O and LiPr 5 Si 4 N 10 O – Chain‐Type Oxonitridosilicates

The isotypic lithium rare‐earth oxonitridosilicates Li Ln 5 Si 4 N 10 O ( Ln = La, Pr) were synthesized at temperatures of 1200 °C in weld shut tantalum ampoules employing liquid lithium as flux. Thereby, a silicate substructure with a low degree of condensation was obtained. LiLa 5 Si 4 N 10 O crystallizes in space group P $\bar{1}$ [ Z = 1, LiLa 5 Si 4 N 10 O: a = 5.7462(11), b = 6.5620(13), c = 8.3732(17) Å, α = 103.54(3), β = 107.77(3), γ = 94.30(3), wR 2 = 0.0405, 1315 data, 96 parameters]. The nitridosilicate substructure consists of loop branched dreier single‐chains of vertex sharing SiN 4 tetrahedra. Lattice energy calculations (MAPLE) and EDX measurements confirmed the electrostatic bonding interactions and the chemical compositions. The 7 Li solid‐state MAS NMR investigation is reported.