| Summary: | 碩士 === 國立中央大學 === 化學學系 === 102 === Two uranium phosphates, Na2U(PO4)2 (A1) and K4[(UO2)3O2(PO4)2] (A2), were synthesized under hydrothermal
conditions at 600 °C and 155 MPa. Both of these two structures were determined by single-crystal X-ray diffraction. The purity of each compound was confirmed by powder X-ray diffraction. These compounds were further characterized by EDS, EPMA and UV-vis spectroscopy.
Compound A1 is a new uranium(IV) phosphate. Its crystal structure contains 1D chains of vertex- and edge-sharing UO8 snub-disphenoidal polyhedra, which are linked by sharing edges with PO4 tetrahedra to form a 3D framework. Crystal data: Na2U(PO4)2, orthorhombic, Fddd (No. 70), a = 6.9485(5) Å ， b = 11.7506(8) Å ， c = 17.3544(11) Å ， V = 1416.97(17) Å 3，Z = 6， R1 = 0.0120 and wR2 = 0.0368.
Compound A2 is a uranium(VI) phosphate. Its crystal structure contains two unique U atoms with different coordination environments. U(1) is pentagonal bipyramidal and U(2) is hexagonal bipyramidal. The compound adopts the phosphuranylite type structure. The sheet anion topology approach was used for the description of this complex structure. Crystal data: K4[(UO2)3O2(PO4)2], monoclinic, P21/c (No. 14)， a = 6.7323(4) Å ， b = 16.8465(10) Å， c = 7.0415(4) Å， = 99.250(2)°， V = 788.23(8) Å 3， Z = 2，
R1 = 0.0261 and wR2 = 0.0674.
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