Synthesis, Crystal Structure, and Properties of REE Nitrate Complexes with a Nitrosonium Cation

Nitrate REE complexes with a nitrosonium cation (NO)₃[Ln₂(NO₃)₉] Ln = La (1), Ce (2), Eu (3), Gd (4), Tb (5), Dy (6)); (NO)₂[Ln(NO₃)₅], Ln = Er (8), Tm (9), Yb (10), Y (11); Na(NO)[Y(NO₃)₅] (12), Na(NO)[Y(NO₃)₅] (13), and NO[Ho(NO₃)₄] (14) are prepared by the crystallization from nitric-acid solutions and structurally characterized by XRD. Depending on the REE radius, the following different coordination polyhedra and types of structures can formed: 3D anionic framework with a [LnO₁₂] (Ln = La–Dy) icosahedral polyhedron; island structures with a [LnO₁₀] (Ln = Er–Y) tetradodecahedron, and 1D chains in the case of holmium with an environment responding to a bicapped tetragonal antiprism. In 1-14, NO⁺ participates in quite strong N⋯O and O⋯O interactions c nitrate groups. The influence of lanthanide compression on the geometry of complex polyhedra is discussed; features of NO⁺ coordination are considered. It is shown on the example of 3, 6, 10 that thermolysis leads to consecutive formation of anhydrous nitrates, LnONO₃ oxonitrates, and REE oxides. The magnetic susceptibility study of 8 revealed no noticeable deviations from paramagnetic behavior.