Abstract
A new indium terbium germanate InTbGe 2O 7, which is a member of the thortveitite family, was prepared as a polycrystalline powder material by high-temperature solid-state reaction. This new compound crystallizes in the monoclinic system, space group C2/ c (No. 15), with unit cell parameters a=6.8818(2) Å, b=8.8774(3) Å, c=9.7892(4) Å, β=101.401(1)°, V=586.25(4) Å 3 and Z=4. Its structure was characterized by Rietveld refinement of powder laboratory X-ray diffraction data. It consists of octahedral sheets that are held together by sheets of isolated Ge 2O 7 diorthogroups composed of two tetrahedra sharing a common vertex. It contains only one octahedral site occupied by In 3+ and Tb +3 cations. The characteristic mirror plane in the thortveitite (Sc 2Si 2O 7) space group ( C2/ m, No. 12) is not present in this new compound. Besides, in InTbGe 2O 7, the Ge–O–Ge angle bridging two diorthogroups is 156.8(2)° as compared to the one in thortveitite, which is 180°. On the other hand, luminescent properties were observed when it is excited with 376.5 nm wavelength. The luminescence spectrum shows typical transitions from the 5D 4 multiplet belonging to the trivalent terbium ion.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
