Hydrothermal synthesis and structural characterization of Fe(II)-squarate Fe 2(OH) 2(C 4O 4)

Abstract

Fe 2(OH) 2(C 4O 4) was obtained by hydrothermal synthesis starting from a mixture of FeC 2O 4:H 2C 4O 4:(CN 3H 5) 2,H 2CO 3 (guanidinium carbonate):H 2O in the molar ratio 1:0.5:1.5:200 after a heat treatment at 200 °C for 96 hours. It crystallizes in the monoclinic system, space group P2 1/c with lattice parameters a=3.3500(2) Å, b=10.033(1) Å, c=8.5010(7) Å, β=99.686(5)°, V=281.65(4) Å 3, Z=2. The framework is built up from isolated double chains of [Fe(OH) 3O 3] octahedra sharing edges along the direction [100] and which are connected in the [010] and [001] directions via squarate groups [C 4O 4] 2−: each squarate group being connected to four iron (II)-oxygen double chains.