二草酸合铜(Ⅱ)酸钾的固相合成、晶体结构与表征

Solid-Phase Synthesis,Crystal Structure and Characterization of Potassium Copper(Ⅱ) Oxalate

以草酸钾和乙酸铜为原料,通过室温固相反应制备二草酸合铜(Ⅱ)酸钾配合物,用容量分析、X射线单晶衍射、X射线粉末衍射、红外光谱及热分析等方法进行组成与结构表征.实验结果表明,所制得的二草酸合铜(Ⅱ)酸钾的组成为K_2[Cu(C_2O_4)_2]·2H_2O,晶体结构属于三斜晶系,P 1空间群,晶胞参数为:a=0.693 08(5)nm,b=0.869 91(6)nm,c=0.901 11(7)nm,α=108.315(2)°,β=99.906(2)°,γ=97.179(2)°,Z=2,Dc=2.356 g·cm^(-3).铜(Ⅱ)与草酸根中的氧原子及水分子中的氧原子配位,形成配位数为6的变形八面体配合物.该配合物在氮气气氛中的热分解过程包括失水、脱CO_2和脱CO,残余物为Cu和K_2CO_3.

The complex of potassium copper（ Ⅱ ） oxalate was synthesized with potassium oxalate and copper acetate as the raw materials by a room-temperature solid-phase reaction. The composition and structure of the com- plex were characterized by titration analyses, single crystal X-ray diffraction, X-ray powder diffraction, infrared spectroscopy and thermal analysis. The crystal structure of the complex K2 [ Cu（ C2O4 ）2 ] · 2H2O belonged to the triclinic system with the space group P 1 and cell parameters of a =0. 693 08（5） nm, b =0.869 91 （6） nm, c = 0.901 11（7） nm, a=108.315（2）°,β=99.906（2）°, γ=97. 179（2）°, Z=2, and Do =2.356 g - cm-3. The Cu （ Ⅱ ） ion was hexacoordinated by six oxygen atoms from oxalate ligands and water molecules, forming an axial elongated octahedral geometry. The thermal decomposition process of the complex in the nitrogen atmosphere was found to be in three steps： dehydration, carbon dioxide removal and carbon monoxide removal, with the final resi- dues to be Cu and K2CO3.