Inorganic Chemistry, Vol.55, No.20, 10229-10237, 2016
Structure and Magnetic Behavior of Layered Honeycomb Tellurates, BiM(III)TeO6 (M = Cr, Mn, Fe)
New layered honeycomb tellurates, BiM(III)-TeO6 (M = Cr, Mn, Fe) were synthesized and characterized. BiM(III)TeO6 (M = Cr, Fe) species crystallize in a trigonal space group, P (3) over bar 1c (No. 163), of edge-sharing M3+/Te6+O6 octahedra, which form honeycomb-like double layers in the ab plane with Bi3+ cations located between the layers. Interestingly, the structure of BiMnTeO6 is similar to those of the Cr/Fe analogues, but with monoclinic space group, P2(1)/c (No. 14), attributed to the strong Jahn-Teller distortion of Mn3+ cations. The crystal structure of BiM(III)TeO6 is a superstructure of PbSb2O6-related materials (ABB'O-6). The Cr3+ and Fe3+ cations are ordered 80% and 90%, respectively, while the Mn3+ ions are completely ordered on the B-site of the ABB'O-6 structure. BiCrTeO6 shows a broad antiferromagnetic transition (AFM) at similar to 17 K with a Weiss temperature (theta) of -59.85 K, while BiFeTeO6 and BiMnTeO6 show sharp AFM transitions at similar to 11 K with theta of -27.56 K and at similar to 9.5 K with theta of -17.57 K, respectively. These differences in the magnetic behavior are ascribed to the different concentration of magnetic nearest versus next-nearest neighbor interactions of magnetic cations due to the relative differences in the extent of M/Te ordering.