2020/09/15 by M. Touaiher, K. Benkhouja
#Diphosphate #EPR #Magnetism #Manganese #Structure #Zinc #specific heat .
paper · doi:10.48317/imist.prsm/morjchem-v7i2.14618
The structure of the diphosphate ZnMnP2O7 is determined on powder by the Rietveld method. It is of monoclinic symmetry C2/m. The cell parameters are: a = 6.6141(3) Å, b = 8.4366 (3) Å, c = 4.5305(2) Å and b= 103.948(2) °. The structural framework is built by MO6 octahedron planes where M is a mixed site statistically occupied by Zn2+ and Mn2+ ions. These planes are parallel to the crystallographic plane (001) and are linked together by sheets of P2O74- groups.The value of the paramagnetic temperature Qp is -4 K, which proves that the interactions are antiferromagnetic . The magnetic specific heat of this compound has a symmetric maximum at T = 5.3 K less acute compared to that of Mn2P2O7 of isotypic structure which is of ltype. This behavior change can be explained by the interruption of three-dimensional interactions between Mn2+ ions which become limited to 2D order when 50% of these ions are replaced by Zn2+ ions.