Crystal structure of novel layered iron arsenate-oxalate (NH4)3K3[Fe2(HAsO4)2(C2O4)4]∙2H2O

Abstract

A new open-framework structure of iron arsenate-oxalate (NH₄)₃K₃[Fe₂(HAsO₄)₂(C₂O₄)₄]∙2H₂O (I) is synthesized by slow evaporation and structurally characterized by single crystal X-ray diffraction methods. It crystallizes in the triclinic space group \(P\overline 1 \) (No. 2), with a = 10.154(4) Å, b = 10.430(4) Å, c = 15.085(7) Å, α = 96.81(3)°, β = 105.04(43)°, γ = 93.93(3)°, V = 1523.7(11) ų and Z = 2. Its crystal structure consists of two crystallographically independent bishydrogenarsenato tetraoxalato diiron(III) anions, both located on centres of inversion, while the potassium and ammonium cations and water molecules are located in general positions.These moieties are connected through N–H…O and O–H…O hydrogen bonds to form infinity of layers parallel to the (101) plane, thus leading to a two-dimensional open framework.