Chemical preparation, crystal structure and characterization of the new sodium ytterbium cyclotriphosphate Na3Yb(P3O9)2·9H2O

Chemical preparation and crystal structure are reported for a new lanthanide cyclotriphosphate Na3Yb(P3O9)2·9H2O. This salt crystallizes in the trigonal system, space group R3¯c with the following parameters: a = 30.933(2), c = 12.8282(5) Å. The crystal structure was refined to R1 = 0.0432 using 1782 reflections with I > 2 σ(I). In the Na3Yb(P3O9)2·9H2O structure, the phosphoric ring anions, located around the 3¯ axis are interconnected by YbO8 dodecahedra and NaO6 and NaO7 polyhedra to build, around the threefold axis, large channels parallel to the c axis. All the nine water molecules in the present arrangement participate in the coordination spheres of the associated cations. The thermogravimetric analysis shows that the removal of these water molecules occurs in three stages between 305 and 736 K.The vibrational study by IR absorption spectroscopy of Na3Yb(P3O9)2·9H2O is also reported.