A new triphosphate TlFeHP3O10 was obtained by the hydrothermal method. It crystallizes in the monoclinic space group C2/c with a=11.994 (5), b= 8.476 (2), c=9.276 (3), β=111.99 (3), V=874.4 (5) and Z=4. The structure was determined by single-crystal X-ray diffraction data collection and provides a clear identification of hydrogen bonds interconnecting the triphosphoric groups in order to build HP3O10 connected by FeO6 octhaedra sharing corners. Thallium cations are located in tunnels. This arrangement was confirmed by CHARDI and BVS models. IR spectrum confirms that most of the vibrational modes are comparable to similar triphosphates and to the calculated frequencies. BVSP and BVSE models were used to simulate conduction pathways migration in the tree dimensional framework. The Bond valence analysis revealed that Tl + conductivity was one dimensional insured by crystal sites with an activation energy 0.664 eV. However, H + conductivity was insured by both crystal sites and interstitials with 0.682 eV migration energy for one dimensional conductivity and 1.293 eV for three dimensional migrations.

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Na1.5MnII3MnIII0.5(AsO4)3 and Na1.5MnII3FeIII0.5(AsO4)3 compounds were synthesized via a high-temperature solid-state combustion reaction. The obtained samples were submitted to structural, morphological, and electrical characterizations. X-ray diffraction measurements revealed that both compounds crystallize in the monoclinic system with the space group P21/c. The lattice parameters were determined to be a = 6.78344 Å, b = 12.93830 Å, c = 11.22825 Å, and β = 98.5374° for Na1.5MnII3MnIII0.5(AsO4)3, and a = 6.76723 Å, b = 12.9864 Å, c = 11.256 Å, and β = 98.8636° for Na1.5Mn2+3Fe3+0.5(AsO4)3. The structures consist of octahedral MnII and MnIII or FeIII ions connected by sharing edges, forming infinite chains. These chains are further connected by AsO4 tetrahedra, resulting in a three-dimensional anionic framework with tunnels parallel to the a-direction and cavities according to the c-direction. The structural models were validated using bond valence and charge distribution analyses. In addition to the structural characterization, the electric results depended on the crystal structures, indicating the potential of the studied materials for being used in several applications.

A new iron arsenate Na1.82K0.38Rb0.80Fe3(AsO4)4 (1), with layer structure has been synthesized by solidstate method and studied by X-ray diffraction. It crystallizes in orthorhombic space group Cmce with lattice parameters a=10.8710(9)Å, b=20.882(2)Å, c=6.5163(7)Å, V= 1479.3(2)Å 3 and Z = 4. The final agreement factors are R = 0.039 and wR = 0.109. The X-ray single-crystal structure reveals a layered structure. Each layer is made of AsO4 tetrahedra and FeO6 octahedra sharing corners and edges. The Rb + and K + reside between the undulating iron arsenate slabs, whereas the smaller Na + cations are located in the cavities of the anionic framework. The structural model was validated by bond valence sum (BVS), distortion indices (DI) and charge distribution (CD) methods. Pathways migration simulation of alkali cations was studied by extended BVS models (BVSP and BVEL).