Iron(II/III) sulfite and sulfates for oxygen adsorption and degradation of methyl orange

[Fe(H2O)(6)]center dot 2HSO(4)center dot 2H(2)O (1), (NH4)(2)[Fe(SO3)(2)] (2) and (NH4)(4)[Fe-2(SO4)(4)(OH)(2)]center dot NaCl (3) have been synthesized and well characterized by elemental, IR spectra, thermal and X-ray structural analyses, and theoretical bond valence calculations. Octahedral Fe(H2O)(6)(2+) and tetrahedral SO42- ions are connected by hydrogen bonds to form three-dimensional network in 1. Coordination of iron with sulfite forms a 2D snowflake structure in 2. The iron(III) atoms in 3 are connected to each other to form a helical chain by two sulfates and one hydroxide. The iron chains are further connected into a 3D network by sodium atoms. Moreover, the catalytic performances of 1 and 3 were tested by the degradations of methyl orange respectively. 1 possesses small channels with dimensions of 3.5 x 1.8 angstrom. It can selectively adsorb a small amount of O-2 for 23.83 mg/g at 29.9 bar, comparing with a few or no adsorptions of N-2, H-2, CO2 and CH4 respectively.