Frost Ray L, Cejka Jirí, Weier Matt L, Martens Wayde, Kloprogge J Theo
Inorganic Materials Research Program, School of Physical and Chemical Sciences, Queensland University of Technology, G.P.O. Box 2434, Brisbane, Qld 4001, Australia.
Spectrochim Acta A Mol Biomol Spectrosc. 2006 May 15;64(2):308-15. doi: 10.1016/j.saa.2005.07.028.
Raman spectroscopy has been used to study the molecular structure of a series of selected uranyl silicate minerals, including weeksite K2[(UO2)2(Si5O13)].H2O, soddyite [(UO2)2SiO4.2H2O] and haiweeite Ca(UO2)2(Si5O12(OH)23 with UO2(2+)/SiO2 molar ratio 2:1 or 2:5. Raman spectra clearly show well resolved bands in the 750-800 cm-1 region and in the 950-1000 cm-1 region assigned to the nu1 modes of the (UO2)2+ units and to the (SiO4)4- tetrahedra. For example, soddyite is characterized by Raman bands at 828.0, 808.6 and 801.8 cm-1 (UO2)2+ (nu1), 909.6 and 898.0 cm-1 (UO2)2+ (nu3), 268.2, 257.8 and 246.9 cm-1 are assigned to the nu2 (delta) (UO2)2+. Coincidences of the nu1 (UO2)2+ and the nu1 (SiO4)4- is expected. Bands at 1082.2, 1071.2, 1036.3, 995.1 and 966.3 cm-1 are attributed to the nu3 (SiO4)4-. Sets of Raman bands in the 200-300 cm-1 region are assigned to nu2 (delta) (UO2)2+ and UO ligand vibrations. Multiple bands indicate the non-equivalence of the UO bonds and the lifting of the degeneracy of nu2 (delta) (UO2)2+ vibrations. The (SiO4)4- tetrahedral are characterized by bands in the 470-550 cm-1 and in the 390-420 cm-1 region. These bands are attributed to the nu4 and nu2 (SiO4)4- bending modes. The minerals show characteristic OH stretching bands in the 2900-3500 cm-1 and 3600-3700 cm-1.
拉曼光谱已被用于研究一系列选定的铀酰硅酸盐矿物的分子结构，包括维克斯矿K2[(UO2)2(Si5O13)].H2O、水硅铀矿[(UO2)2SiO4.2H2O]和海威矿Ca(UO2)2(Si5O12(OH)23，其UO2(2+)/SiO2摩尔比为2:1或2:5。拉曼光谱清楚地显示出在750 - 800 cm-1区域和950 - 1000 cm-1区域有分辨率良好的谱带，分别归属于(UO2)2+单元的ν1模式和(SiO4)4-四面体。例如，水硅铀矿的特征拉曼谱带在828.0、808.6和801.8 cm-1处为(UO2)2+ (ν1)，909.6和898.0 cm-1处为(UO2)2+ (ν3)，268.2、257.8和246.9 cm-1归属于ν2 (δ) (UO2)2+。预计ν1 (UO2)2+和ν1 (SiO4)4-会有巧合。1082.2、1071.2、1036.3、995.1和966.3 cm-1处的谱带归属于ν3 (SiO4)4-。200 - 300 cm-1区域的拉曼谱带组归属于ν2 (δ) (UO2)2+和UO配体振动。多个谱带表明UO键的不等价性以及ν2 (δ) (UO2)2+振动简并性的解除。(SiO4)4-四面体的特征谱带在470 - 550 cm-1区域和390 - 420 cm-1区域。这些谱带归属于ν4和ν2 (SiO4)4-弯曲模式。这些矿物在2900 - 3500 cm-1和3600 - 3700 cm-1处显示出特征性的OH伸缩谱带。
