| 摘要: | 本論文利用高溫高壓水熱合成法在600 °C 且 165 MPa的狀態下，合成出 uranium(IV) phosphate，Na10U2P6O24 (A1)，利用單晶X光繞射方法收集數據後進行結構解析，再藉由調整合成比例及反應時間以得到化合物的純相抑或是主要產物。利用粉末 X 光繞射圖譜與理論圖譜做比對以確定樣品純度供後續物理性質的測量；利用 UV-vis 吸收光譜圖和 U 4f X 光光電子光譜圖分析，確認鈾的氧化態為四價；磁性分析其化合物具反鐵磁性質；倍頻訊號量測佐證非中心對稱結構的存在。
改變反應物調整合成比例及反應時間以得到 A1 的等結構化合物Na10Ce2P6O24 (A2)。利用粉末 X 光繞射圖譜與理論圖譜做比對以確定晶體結構；倍頻訊號量測佐證非中心對稱結構的存在；利用 UV-vis 吸收光譜圖確認鈰的氧化態為四價。
此晶體主要結構為，PO4形成的磷酸四面體藉由頂點和邊共享氧原子的方式與UO8 snub-disphenoidal的多面體連結，形成一個具有12員環孔道的 3-D 結構。結構中的十個鈉離子填滿在孔道中。
這是第一個四價鈾磷酸鹽化合物在高溫高壓水熱條件下合成，晶體數據如下: Na10U2P6O24, orthorhombic, P212121 (No. 19), a = 6.9289(3) ?, b = 16.1850(7) ?, c = 18.7285(7) ?, V = 2100.3(2) ?3, Z = 4, R1 = 0.0304, and wR2 = 0.0522.
A uranium(IV) phosphate, Na10U2P6O24 (A1), was synthesized under hydrothermal conditions at 600 °C and 165 MPa and structurally characterized by single-crystal X-ray diffraction. The valence state of uranium was established by UV-vis and U 4f X-ray photoelectron spectroscopy. The powder sample has a second-harmonic-generation signal, confirming the absence of a center of symmetry in the structure.
A cerium (IV) phosphate, Na10Ce2P6O2 (A1), was synthesized under hydrothermal conditions at 600 °C and 165 MPa. The powder sample has a second-harmonic-generation signal, confirming the absence of a center of symmetry in the structure. The valence state of cerium was established by UV-vis spectroscopy.
The structure contains UO8 snub-disphenoidal polyhedra which are linked to monophosphate tetrahedra by vertex- and edge-sharing such that a 3-D framework with 12-sided circular and rectangular channels is formed. All ten sodium sites are situated inside the channels and are fully occupied.
This is the first uranium(IV) phosphate synthesized under high-temperature, high-pressure hydrothermal conditions. Crystal data: Na10U2P6O24, orthorhombic, P212121 (No. 19), a = 6.9289(3) ?, b = 16.1850(7) ?, c = 18.7285(7) ?, V = 2100.3(2) ?3, Z = 4, R1 = 0.0304, and wR2 = 0.0522. |
