Frost Ray L, Weier Matt L, Cejka Jirí, Ayoko Godwin A
Inorganic Materials Research Program, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Qld 4001, Australia.
Spectrochim Acta A Mol Biomol Spectrosc. 2006 Nov;65(3-4):529-34. doi: 10.1016/j.saa.2005.12.004. Epub 2006 Mar 9.
Raman spectroscopy at 298 and 77K has been used to study the mineral kamotoite-(Y), a uranyl rare earth carbonate mineral of formula Y(2)(UO(2))(4)(CO(3))(3)(OH)(8).10-11H(2)O. The mineral is characterised by two Raman bands at 1130.9 and 1124.6 cm(-1) assigned to the nu(1) symmetric stretching mode of the (CO(3))(2-) units, while those at 1170.4 and 862.3 cm(-1) (77K) to the deltaU-OH bending vibrations. The assignment of the two bands at 814.7 and 809.6 cm(-1) is difficult because of the potential overlap between the symmetric stretching modes of the (UO(2))(2+) units and the nu(2) bending modes of the (CO(3))(2-) units. Only a single band is observed in the 77K spectrum at 811.6 cm(-1). One possible assignment is that the band at 814.7 cm(-1) is attributable to the nu(1) symmetric stretching mode of the (UO(2))(2+) units and the second band at 809.6 cm(-1) is due to the nu(2) bending modes of the (CO(3))(2-) units. Bands observed at 584 and 547.3 cm(-1) are attributed to water librational modes. An intense band at 417.7 cm(-1) resolved into two components at 422.0 and 416.6 cm(-1) in the 77K spectrum is assigned to an Y(2)O(2) stretching vibration. Bands at 336.3, 286.4 and 231.6 cm(-1) are assigned to the nu(2) (UO(2))(2+) bending modes. U-O bond lengths in uranyl are calculated from the wavenumbers of the uranyl symmetric stretching vibrations. The presence of symmetrically distinct uranyl and carbonate units in the crystal structure of kamotoite-(Y) is assumed. Hydrogen-bonding network related to the presence of water molecules and hydroxyls is shortly discussed.
利用298K和77K下的拉曼光谱研究了卡莫托矿 - (Y)，一种化学式为Y₂(UO₂)₄(CO₃)₃(OH)₈·10 - 11H₂O的铀酰稀土碳酸盐矿物。该矿物的特征在于，在1130.9和1124.6 cm⁻¹处有两个拉曼峰，归属于(CO₃)²⁻单元的ν₁对称伸缩振动模式；而在1170.4和862.3 cm⁻¹（77K）处的峰归属于δU - OH弯曲振动。由于(UO₂)²⁺单元的对称伸缩振动模式与(CO₃)²⁻单元的ν₂弯曲振动模式可能重叠，所以很难确定814.7和809.6 cm⁻¹处两个峰的归属。在77K光谱中，仅在811.6 cm⁻¹处观察到一个峰。一种可能的归属是，814.7 cm⁻¹处的峰归属于(UO₂)²⁺单元的ν₁对称伸缩振动模式，而809.6 cm⁻¹处的第二个峰归因于(CO₃)²⁻单元的ν₂弯曲振动模式。在584和547.3 cm⁻¹处观察到的峰归因于水分子的平动模式。在77K光谱中，417.7 cm⁻¹处的一个强峰分解为422.0和416.6 cm⁻¹处的两个组分，归属于Y₂O₂伸缩振动。336.3、286.4和231.6 cm⁻¹处的峰归属于(UO₂)²⁺的ν₂弯曲振动模式。根据铀酰对称伸缩振动的波数计算了铀酰中的U - O键长。假定在卡莫托矿 - (Y)的晶体结构中存在对称不同的铀酰和碳酸盐单元。简要讨论了与水分子和羟基存在相关的氢键网络。
