Crystal structure and infrared spectrum of thallium holmium polyphosphate, TlHo(PO3)4

Crystals of thallium-holmium polyphosphate TlHo(PO3)4 were grown by flux method technique and characterized by single crystal X-ray diffraction. Structure of TlHo(PO3)4 was solved for the first time, and it crystallized in the monoclinic P21/n space group with the following unit-cell dimensions: a=1.02225(3) nm, b=0.88536(2) nm, c=1.09541(4) nm, β=105.888(1)®, V=0.95354(5) nm3 and Z=4. The crystal structure was solved from 2174 independent reflections with final R1(F2)=0.0442 and Rw(F2)=0.0861 refined with 164 parameters. The atomic arrangement could be described as a long chain polyphosphate organization. Holmium atoms had eightfold coordination. The structure of TlHo(PO3)4 consisted of HoO8 polyhedra sharing oxygen atoms with phosphoric group PO4. Infrared spectrum was investigated at room temperature in the frequencies range, 350–4000 cm−1, showing some characteristic vibration bands of infinite chain structure of PO4 tetrahedra linked by bridging oxygen.