Polynuclear coordination precursors compounds for M3Fe5O12 garnets (M=Y, Eu, Gd and Er), Part I: Synthesis of the precursors

A new type of complexes compounds (NH 4 ) 6 [M 3 Fe 5 (C 4 O 5 H 4 ) 6 (C 4 O 5 H 3 ) 6 ] 16H 2 O (where M(III) = Y, Eu, Gd, Er), (NH 4 ) 6 [M 3 Fe 5 (C 4 O 6 H 4 ) 6 (C 4 O 6 H 3 ) 6 ]. 16H 2 O (where M(III) = Gd, Er) and (NH 4 ) 6[M 3 Fe 5 (C 6 O 7 H 1 0 ) 6 (C 6 O 7 H 9 ) 6 ] xH 2 O (where M(III) = Y; x = 8; M(III) = Eu, Er; x = 22) [C 4 O 5 H 4 2 = malate anion; C 4 O 4 H 4 2 - = tartaratc anion, C 6 O 7 H 1 1 = gluconate anion] have been synthesized and characterised by elemental chemical analysis and physico-chemical measurements (1R, UV-Vis spectroscopy and magnetic determinations). The synthetic possibilities offered by the use of these new compounds as potential precursors for garnets have been suggested.