Spectra and diagrams from single-crystal Raman spectroscopy of natural paulmooreite Pb2As2O5 in comparison with the synthesized analog

Paulmooreite is a lead arsenite mineral containing dimeric [As2O5]4− units.  A natural paulmooreite sample was kindly supplied by the Swedish Museum of Natural History (specimen number NRM532109). In preparing a synthetic analog of paulmooreite, hydrothermal and wet synthetic methods were explored including the method given by ( Pertlik, F (1988) The single chain arsenites Pb(AsO2)3Cl. Preparation and structure investigation. Zeitschrift für Kristallographie, 184, 191-201) who reported the presence of Pb2As2O5 among the products of the hydrothermal synthesis of Pb2(AsO2)3Cl.

Figure 1 is (a) [As2O5]4− dimer in parallel orientation (As = light gray). (b) [As2O5]4− dimer in paulmooreite (90° orientation).  Figure 2 shows XRD pattern of the product of reaction P3 and Figure 3 XRD pattern of the product of reaction H1.   Figure 4 is (a) SEM micrograph of product of reaction W1. (b) SEM micrograph of product of reaction W2.  Figure 5 shows the Raman spectra of natural and synthetic paulmooreite in the 800–100 cm−1 region.  Figure 6 is oriented single-crystal spectra of natural paulmooreite in the 830–670 cm−1 region.  Figure 7 shows oriented single-crystal spectra of synthetic paulmooreite in the 900–550 cm−1 region.  Figure 8 is oriented single-crystal spectra of synthetic paulmooreite in the 600–100 cm−1 region. Figure 9 is oriented single-crystal spectra of natural paulmooreite in the 700–250 cm−1 region.  Figure 10 shows oriented single-crystal spectra of natural paulmooreite in the 250–100 cm−1 region.  Figure 11 is stacked Raman spectra of paulmooreite, Pb5(AsO3)3Cl, PbAs2O4, Pb2(AsO2)3Cl, and HF calculated Raman spectrum of paulmooreite.

保摩尔矿（Paulmooreite）是一种含二聚体[As₂O₅]⁴⁻结构单元的亚砷酸铅矿物。天然保摩尔矿样品由瑞典自然历史博物馆惠赠（标本编号NRM532109）。在制备保摩尔矿的合成类似物时，研究人员探索了水热法与湿合成法，其中包括Pertlik F于1988年发表的方法——该研究在《The single chain arsenites Pb(AsO₂)₃Cl. Preparation and structure investigation. Zeitschrift für Kristallographie, 184, 191-201》中报道，在水热合成Pb₂(AsO₂)₃Cl的产物中检出了Pb₂As₂O₅。图1为(a) 平行取向的[As₂O₅]⁴⁻二聚体（As为浅灰色）；(b) 保摩尔矿中呈90°取向的[As₂O₅]⁴⁻二聚体。图2展示了反应P3产物的X射线衍射（XRD）图谱，图3为反应H1产物的X射线衍射图谱。图4为(a) 反应W1产物的扫描电子显微镜（SEM）显微照片；(b) 反应W2产物的扫描电子显微镜显微照片。图5展示了天然与合成保摩尔矿在800~10 cm⁻¹波数区间的拉曼光谱。图6为天然保摩尔矿在830~670 cm⁻¹波数区间的定向单晶光谱。图7展示了合成保摩尔矿在900~550 cm⁻¹波数区间的定向单晶光谱。图8为合成保摩尔矿在600~100 cm⁻¹波数区间的定向单晶光谱。图9为天然保摩尔矿在700~250 cm⁻¹波数区间的定向单晶光谱。图10展示了天然保摩尔矿在250~100 cm⁻¹波数区间的定向单晶光谱。图11为保摩尔矿、Pb₅(AsO₃)₃Cl、PbAs₂O₄、Pb₂(AsO₂)₃Cl的拉曼光谱叠加图，以及保摩尔矿的计算拉曼光谱。