Najoua Ouerfelli

α-NH4Fe(HAsO4)2.

The title compound α-ammonium iron(III) bis[hydrogen arsenate(V)], α-NH4Fe(HAsO4)2 (or poly[ammonium bis(μ-hydrogen arsenato)ferrate(III)], {NH4[Fe(HAsO4)2]}n), synthesized hydrothermally, is isostructural with NH4Fe(HPO4)2. Condensation of the hydrogen arsenate groups with FeO6 coordination octahedra via common corners results in an overall three-dimensional framework containing interconnected channels parallel to the a-, b- and c-axis directions. The NH4 + cations are located in three intersecting tunnels, which is promising as an ion exchange. Hydrogen bonding of the types O—H⋯O and N—H⋯O consolidates the packing of the structure. The distortion of the coordination polyhedra is analyzed by means of the effective coordination number and distortion indices. Structural relationships with other compounds of general formula M I M III[HXO4)]2 (X = P, As) are discussed.

Composé à charpente bidimensionnelle K3Fe3(AsO4)4

Tripotassium triiron(III) tetraarsenate, K3Fe3(AsO4)4, has been synthesized at high temperature by solid-state reaction. The structure is built up from corner- and edge-sharing between FeO6 octahedra and AsO4 tetrahedra. The structure can be described as infinite anionic layers parallel to the (010) plane. Alkali metal cations are located in the interlayer space. The relationship between the title compound and K3Fe3(PO4)4·H2O structures is discussed. The title compound is isostructural with K3Cr3(AsO4)4.

Un nouveau diarséniate Cs3Fe2(AsO4)3à environnement exclusivement pentagonal du fer

The crystal structure of the new iron(III) arsenate, viz. tricaesium diiron(III) tris(arsenate), Cs3Fe2(AsO4)3, is built up from corner-sharing AsO4 tetrahedra and FeO5 trigonal bipyramids forming a three-dimensional open framework, which contains two channels running along the c axis where the Cs+ cations are located. This compound is a rare example of an oxide possessing Fe exclusively in trigonal–bipyramidal coordination.

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

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

Synthesis, crystal structure and mono-dimensional thallium ion conduction of TlFe0.22Al0.78As2O7

P\overline 1

Synthesis, crystal structure and electrical properties of a new iron arsenate Na 2.77 K 1.52 Fe 2.57 (AsO 4 ) 4

P1¯ (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) Å3 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.