Static field induced magnetic relaxations in dinuclear lanthanide compounds of [phen2Ln2（HCOO）4（HCOO）2-2x（NO3）2x] （1, Ln = Gd and x = 0.52; 2, Ln = Er and x = 0.90; phen = 1,10-phenanthroline）

Two dinuclear lanthanide （Ln） complexes, formulated as [phen2Ln2（HCOO）4（HCOO）2 2x（NO3）2x] （1, Ln = Gd and x = 0.52; 2, Ln = Er and x = 0.90; phen = 1,10-phenanthroline）, were synthesized and characterized. They are isostructural. The dinuclear molecule consists of two Ln3＋ bridged by four formate groups and chelated by phen and formate/nitrate ligands, and the Ln3＋ possesses a coordination environment of distorted tri-capped trigonal prism of LnOTN2. Both compounds behave as paramag- nets between 2 and 300 K, but display two static field induced magnetic relaxation processes. One is slow and of spin-lattice type, and it results from the lifting of Kramer＇s degeneracy of the ground-states of both Gd3＋ and Er3＋, and the other is fast, and it might be spin-spin type.