Extreme condition high temperature and high pressure studies of the K-U-Mo-O system.
Extreme condition high temperature and high pressure studies of the K-U-Mo-O system.
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DOI：
10.1039/d0dt03367g
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发表时间：
2020-11
影响因子：
4
通讯作者：
Gabriel L. Murphy;P. Kegler;M. Klinkenberg;Shuao Wang;E. Alekseev
中科院分区：
文献类型：
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作者：
Gabriel L. Murphy;P. Kegler;M. Klinkenberg;Shuao Wang;E. Alekseev
本文描述并表征了使用高温高压（HT/HP）方法的极端条件合成的碱土金属铀酰杂多酸盐的第一个实施例，即K2[UO 2（Mo 2 O 7）2]、K2[（UO 2）2（Mo（vi）4 Mo（iv）（OH）2）O 16]、K3[（UO 2）6（OH）2（MoO 4）6（MoO 3 OH）]和K5[（UO 2）10 MoO 5 O 11 OH]·H2 O。K2[UO 2（Mo 2 O 7）2]形成单斜二维层状结构，空间群为P21/c，由相互连接的Mo 2 O 7二聚体组成，这些二聚体连接孤立的UO 22+部分，形成[UO 2（Mo 2 O 7）2]2-层，这些层被K+阳离子隔开。K2[（UO 2）2（Mo（vi）4 Mo（iv）（OH）2）O 16]在空间群P1[结合macron]中形成无序的三斜晶系3D骨架结构。该结构由孤立的UO 22+部分连接在一个分层的配置通过Mo（VI）O 6多面体的层被桥接的Mo（IV）O 6多面体，部分位置无序的电荷平衡K+和桥接Mo 4+阳离子。K3[（UO 2）6（OH）2（MoO 4）6（MoO 3OH）]是一种无序的斜方晶系三维骨架结构，空间群Pbcm，由MoO 4和UO 22+两个角上的小孔道和大空穴组成，分别包裹有序和无序的K+阳离子。K5[（UO 2）10 MoO 5 O 11 OH]·H2O在空间群P1[结合macron]中形成三斜晶系三维骨架结构，由相互连接的UO 6、UO 7和MoO 5多面体组成，这些多面体利用UO 22+部分之间的阳离子-阳离子相互作用产生平行于[001]方向的无限通道，其中包含部分无序的K+阳离子和H2O分子。结合单晶X射线衍射，键价和计算和扫描电子显微镜与能量色散X射线光谱测量被用来在本次调查中所获得的样品。在这项调查中发现的结构进行了系统的详细讨论，与其他成员的更广泛的A+-U-Mo-O系统从文献中的压力施加的程度和U/Mo的比例之间的关系，在合成的能力，通过缩合和低聚多面体获得高维结构的识别和详细讨论。
Herein the first examples of alkali earth uranyl molybdates synthesised using extreme conditions of high temperature and high pressure (HT/HP) methods, namely K2[UO2(Mo2O7)2], K2[(UO2)2(Mo(vi)4Mo(iv)(OH)2)O16], K3[(UO2)6(OH)2(MoO4)6(MoO3OH)] and K5[(UO2)10MoO5O11OH]·H2O, are described and characterised. K2[UO2(Mo2O7)2] forms a monoclinic 2D layered structure in space group P21/c that consists of interlinking Mo2O7 dimers that link isolated UO22+ moieties forming [UO2(Mo2O7)2]2- layers which are separated by K+ cations. K2[(UO2)2(Mo(vi)4Mo(iv)(OH)2)O16] forms a disordered triclinic 3D framework structure in space group P1[combining macron]. The structure consists of isolated UO22+ moieties connected in a layered configuration via Mo(vi)O6 polyhedra of which the layers are bridged by Mo(iv)O6 polyhedra that are partially positionally disordered by charge balancing K+ and bridging Mo4+ cations. K3[(UO2)6(OH)2(MoO4)6(MoO3OH)] adopts a disordered orthorhombic 3D framework structure in space group Pbcm consisting of small channels and large cavities built upon corner sharing MoO4 and UO22+ moieties that respectively encapsulate ordered and disordered K+ cations. K5[(UO2)10MoO5O11OH]·H2O forms a triclinic 3D framework structure in space group P1[combining macron] consisting of interlinking UO6, UO7 and MoO5 polyhedra which utilise cation-cation interactions between UO22+ moieties to create infinite channels parallel to the [001] direction which contain partially disordered K+ cations and H2O molecules. A combination of single crystal X-ray diffraction, bond valence sums calculations and scanning electron microscopy with energy dispersive X-ray spectroscopic measurements was used to characterise all obtained samples in this investigation. The structures uncovered in this investigation are discussed systematically in detail with other members of the broader A+-U-Mo-O system from the literature where the relationship between the degree of pressure applied and U/Mo ratio used during synthesis on the ability to obtain high dimensional structures via condensation and oligomerization of polyhedra is identified and discussed in detail.