Crystal structure and conductivity investigation of KDyP4O12: a new potassium dysprosium cyclotetraphosphate

A single-crystal X-ray diffraction analysis has been performed on KDyP4O12 synthesized by a flux method. The new compound crystallizes at room temperature in the monoclinic space group C2/c with unit cell parameters: a=7.812(2) Å, b=12.318(3) Å, c=10.441(2) Å, β=111.09(2)°, V=937.42(4) Å3 and Dcal=3.66 g cm−3 for Z=4. A full-matrix least square refinement gave R1=0.022, wR2=0.04 for 2421 independent reflections (I>2σ(I)) refined with 84 parameters. ructure is built up from P4O124− cyclotetraphosphate anions linked by DyO8 polyhedra to form a three-dimensional framework, which delimits intersecting oxygen tunnels in which the K+ ions are located. The atomic arrangement can be described as a succession of layers extending along the [010] direction. The P4O124− ring anion is centrosymmetrical is connected by irregularly shaped KO10 polyhedra to form a layer structure parallel to (001). Dysprosium and potassium are surrounded by eight and ten oxygen atoms respectively. s have been examined by impedance and infrared spectroscopy techniques. The reported IR absorption investigation, recorded at room temperature in the frequency range 200–4000 cm−1, shows some bands characteristic of cyclotetraphosphates. ectrical conductivity of KDyP4O12 has subsequently been measured as a function of temperature, it represents a significant ionic conductivity and activation energy (σ=2.15×10−4 Ω−1cm−1 at 453 K and Ea=0.387 eV) corresponding to the mobility of the K+ cations located within tunnels.