Aliovalent anion substitution as a design concept for heteroanionic Ruddlesden-Popper hydrides.

Substituting 2 O 2- ⇒ N 3- + H - in LiLa 2 HO 3 yields dark-brown heteroanionic hydrides, which were synthesized by solid-state reactions from Li 3 N, LaH 3 (and La 2 O 3 ). They crystallize in the K 2 NiF 4 type structure with mixed H/N sites in LiLa 2 N 1.5 H 2.5 and with mixed N/O sites in LiLa 2 N 0.84(6) H 1.56(3) O 1.16(6) . The latter is a semiconductor with small band gap and partly covalent Li-H interaction.