Transformation of the ionic liquid [EMIM][B(CN) 4 ] into anionic and neutral lanthanum tetracyanoborate coordination polymers by ionothermal reactions.

The lanthanum tetracyanoborate coordination polymers [EMIM] [LaNO3 {B(CN)4 }3 (H2 O)3 ] (EMIM = 1-ethyl-3-methylimidazolium) and [La(NO3 )2 [B(CN)4 ](H2 O)4 ] mark first examples of Ln-tetracyanoborates that have been obtained in ionothermal syntheses without further solvents to influence e.g. viscosity. Thereby, the ionic liquid [EMIM][B(CN)4 ] is fully incorporated into product formation.