Synthesis and structural analysis of a homogeneous series of anhydrous rare-earth-metal perchlorates

Abstract

The reaction of Cl₂O₆ with anhydrous or hydrated metal(III) chlorides, nitrates or hydrated perchlorates leads to anhydrous metal perchlorates M(ClO₄)₃(M = Y, La, Nd, Sm, Gd or Er). The complexes are isostructural and crystallise in the monoclinic system (space group P2₁/m): 8.219(6) < a < 8.384(6), 5.602(1) < b < 5.869(9), 7.329(4) < c < 7.481(2)Å, 102.88(4) < β < 104.09(5)°, 328.957 < U < 357.110 ų. Vibrational spectroscopic data show a bridging tridentate co-ordination of ClO₄, and a polymeric layered structure, derived from that of UCl₃, is suggested. Intense fluorescence of Er³⁺ in the Er(ClO₄)₃ complex has been observed. The synthesis and characterisation of three salts, (NO₂)₃Er(ClO₄)₆, ClO₂Er(ClO₄)₄ and (ClO₂)_0.33La(ClO₄)_3.33, are also described.