Unique and contrasting structures of homoleptic lanthanum(iii) and cerium(iii) 3,5-dimethylpyrazolates.

Homoleptic [La(Me2pz)3]n (Me2pz = 3,5-dimethylpyrazolato) is a μ-η2:η5-Me2pz coordination polymer with 12-coordinate La atoms in an unusual η5:η5 Me2pz sandwich, whilst the cerium congener forms a molecular tetrametallic cage [Ce4(Me2pz)12] featuring six different Me2pz coordination modes.