LANTHANUM SAMARIUM OXALATE - ITS GROWTH AND STRUCTURAL CHARACTERIZATION

Lanthanum samarium oxalate (LSO) single crystals are grown in silica g els by the diffusion of a mixture of aqueous solutions of lanthanum ni trate and samarium nitrate into the test tube having the set gel impre gnated with oxalic acid. Tabular crystals of LSO having well defined h exagonal basal planes are observed at different depths inside the gel. LSO crystals grown by this method are colourless and transparent. Lau e transmission X-ray diffraction pattern of LSO reveals well defined s pots with two-fold symmetry along the horizontal axis. Thermogravimetr ic analysis (TGA) and differential scanning calorimetry (DSC) support that LSO loses water around 120 degrees C, and CO and CO2 around 350-4 50 degrees C. The infrared CIR) absorption spectrum of LSO establishes the presence of oxalate (C2O4)(2-) ions. Energy dispersive X-ray anal ysis (EDAX) confirms the presence of La and Sm in the sample. X-ray ph otoelectron spectroscopic (XPS) studies of LSO confirm the presence of La and Sm in their respective oxide states. An empirical structure fo r LSO has been proposed on the basis of these findings.