Abstract
本論文研究主要是以水熱法合成鈷砷酸鹽及磷酸鹽,共有六個新穎鈷砷酸鹽及兩個新穎鈷磷酸鹽化合物被合成出來.可以分為以下四個系列:一.Co2X2O7(H2O)2 (X=As,P); ACoAs2O7 (A=Sr,Ba); VCo(OH)As2O7二.BKCo2(HAsO4)(AsO4)三.BCoCo6(HAsO4)(AsO4)3四.BCuCo2(PO4)(H2O)其中Co2As2O7(H2O)2及Co2P2O7(H2O)2為等結構, 都是單斜晶系, 空間群 P2(1)/n(No.14),它們具有交叉隧道;前者的晶格常數a=6.525(2)埃, b=14.200(5)埃,c=7.618(2)埃,.beta.=94.72(2)度,Z=4,V=703.4(4)立方埃;後者為a=6.354(2)埃,b=14.009(5)埃,c=7.399(2),.beta.=94.69(2)度,Z=4,V=656.3(4)立方埃. SrCoAs2O7的空間群也是P2(1)/n, 晶格常數a=5.520 (2)埃,b=8.391(2)埃,c=13.083(3)埃,.beta.=90.90(2)度,Z=4,V=605.9(3)立方埃; BaCoAs2O7則為三斜晶系, 空間群P-1 (No.2), 晶格常數a=5.545( 2)埃,b=7.310(2)埃,c=7.773(3)埃,.alpha.=101.48(3)度,.beta.=91.66(3 )度, .gamma.=96.45(3)度, Z=2, V=306.4(2)立方埃;這兩個化合物都是由 CoO5形成的四角方錐和As2O7基組成架構,鍶和鋇則位於孔洞中.而VCo(OH)- As2O7 則屬於長方晶系, 空間群Pbam(No.55), 晶格常數a=10.111(1)埃,b =14.090(2)埃,c=8.422(1)埃,Z=8,V=1199.8(3)立方埃.至於KCo2(HAsO4)(AsO4)為一層狀結構,鉀離子位於層間,空間群P2/c (No.13), 晶格常數a=8.787(3)埃,b=5.016(2)埃,c=15.606(6)埃,.beta.= 97.53(3)度, Z=4, V=681.9(4)立方埃; 而CoCo6(OH)3(HAsO4)(AsO4)3是個不具中心對稱的化合物,且對稱高,屬六角晶系,空間群P6(3)mc (No.186),晶格常數a=12.851(4)埃,c=5.115(2)埃, Z=2, V=731.5(4)立方埃.至於 CuCo2(PO4)2(H2O) 這磷酸鹽也是單斜晶系,晶格常數a=8.090(2)埃, b= 9.982(2)埃,c=9.040(2)埃,.beta.=114.85(2)度,Z=4,V=652.2(2)立方埃.以上這些化合物除了用單晶X-光繞射決定結構外,也利用粉末X-光繞射,感應耦合電漿原子發射光譜及X-光能量散佈螢光分析來鑑定組成;同時也利用超導量子干涉磁量儀作磁性測量,還有作熱重量分析以探討它們的磁性和熱性質等物理性質.In this research, cobalt arsenates and phosphates are synth-esized via hydrothermal method. Six new cobalt arsenates andtwo new cobalt phosphates have been obtained. They areclassified into four categories: 1.Co2X2O7(H2O)2 (X=As or P);ACoAs2O7 (A=Sr or Ba); VCo(OH)As2O7 2.KCo2(HAsO4)(AsO4) 3.CoCo6(OH)3(HAsO4)(AsO4)3 4.CuCo2(PO4)2(H2O) Co2As2O7(H2O)2 and Co2P2O7(H2O)2 crystallize in the monocli- nic space group P2(1)/n.Both compounds are isostructural and have intersecting tunnelsin their structures. SrCoAs2O7 also crysta- llizes in themonoclinic space group P2(1)/n. BaCoAs2O7 crysta- llizes in thetriclinic space group P-1. These two compounds' structures areconsisted of CoO5 square pyrimids and As2O7 groups withstrontium or barium ions located in the cavities. VCo(OH)- As2O7 crystallizes in the orthorhombic space group Pbam. KCo2-(HAsO4)(AsO4) crystallizes in the monoclinic space group P2/cand is a layered structure with potassium ions located betweenthe layers.CoCo6(OH)3(HAsO4)(AsO4)3 crystallizesin thenoncentro- symmetric hexagonal space group P6(3)mc.The lastcompound CuCo2- (PO4)2(H2O) crystallizes in the monoclinicspace group P2(1)/n. The above compounds are all structurallycharacterized by si- ngle crystal X-ray diffraction. Mostcompounds' purity and compo- sition are confirmed by powder X-ray diffraction or ICP-AES or EDX. Some are further defined bythermal analysis or magnetic susceptibilities.