الخلاصة:
Oxalate-based compounds have attracted much attention in many areas. Due to their low thermal stability they can be used as precursors of nanocrystalline oxides, e.g., pure BaTiO3 can be produced from the decomposition of barium titanyl oxalate hydrate [1] and, recently, PbZrO3 has been prepared from a new lead zirconium oxalate [2]. Moreover, the presence of cavities in the structures of a number
of them is at the origin of zeolitic properties, arising from weakly bonded water molecules, reported long ago [3-4] and thoroughly studied recently in a few oxalate- and, also, carboxylate-based materials for instance [5–7].A novel 3D crystal structure of the title compound (Ba0.741Sr0.259)C2O4 has been synthesized from precipitation methods at roomtemperature.Its molecular structure was determined by single X-ray diffraction analysis. The compound crystallizes with space group C2/c and the cell parameters are a = 10.348 (5) A°, b = 5.489 (5) A°, c = 8.218 (5) A°, β = 125.09 (5) °, V = 382.0 (5) A° 3, and Z = 4 (R1= 0.026).The crystal structure can be described as double parallel zigzag chains runnning along the c axis and linked together by additional monodentate oxalate-metal bonding. The distance between two chains is b/2. Each metal ion has six O-atom neighbours and they are linked together via the different coordination modes of the oxalate groups, resulting in the formation of a three-dimensional network
