Structures and syntheses of layered and framework amine-bearing uranyl phosphate and uranyl arsenates

[Hg5O2(OH)4][(UO2)2(AsO4)2]: A complex mercury(II) uranyl arsenate

“…3. This unit is also found in Cu[(UO 2 ) 2 (SO 4 ) 2 (OH) 2 ](H 2 O) 8 and Sr[(UO 2 ) 2 (CrO 4 ) 2 (OH) 2 ](H 2 O) 8 [9,27]. The single arsenic center is found as an AsO 3À 4 distorted tetrahedron.…”

“…Uranyl arsenates display remarkably rich crystal chemistry that can be attributed in part to the structural versatility of U(VI), which generally occurs as tetragonal, pentagonal, and hexagonal bipyramids [1][2][3][4][5][6][7][8]. The formation of extended structures containing uranyl polyhedra usually arises only through the equatorial positions owing to the terminal nature of the apical positions, which typically yields two-dimensional structures [9].…”

“…Three oxygen vertices of the AsO 4 tetrahedron are shared with uranyl or mercury. The remaining As(1)-O(1) bond is terminal and short, with a bond distance of 1.661(12) Å indicating an As ¼ O unit [8,31].…”

Hydrothermal Synthesis, Structure and Thermal Stability of Diamine Templated Layered Uranyl‐Vanadates.

“…It should be noticed that with triethylamine, Locock and Burns [17] obtained the same structural arrangement but with another geometrical isomer of the uranyl arseniate layer whereas with dabco molecules an autunite-type uranyl arseniate layer is formed.…”

“…One approach for designing novel layered and microporous uranium-bearing materials is to exert influence over structural features through the introduction of templating agents. Amines have historically been used as charge balancing, space filling and templating agents in various systems including molybdate [9][10][11][12][13], phosphate [14][15][16][17][18], phosphite [19], selenate [20], selenite [21], arsenate [17] sulfate [22][23][24][25][26][27][28][29][30][31] and fluoride containing compounds [18,[31][32][33][34][35][36][37][38][39] but organically templated uranyl-vanadates systems remained unexplored so far.…”