Mixed-Metal Uranium(VI) Iodates:  Hydrothermal Syntheses, Structures, and Reactivity of Rb[UO₂(CrO₄)(IO₃)(H₂O)], A₂[UO₂(CrO₄)(IO₃)₂] (A = K, Rb, Cs), and K₂[UO₂(MoO₄)(IO₃)₂]

Abstract

The reactions of the molecular transition metal iodates A[CrO(3)(IO(3))] (A = K, Rb, Cs) with UO(3) under mild hydrothermal conditions provide access to four new, one-dimensional, uranyl chromatoiodates, Rb[UO(2)(CrO(4))(IO(3))(H(2)O)] (1) and A(2)[UO(2)(CrO(4))(IO(3))(2)] (A = K (2), Rb (3), Cs (4)). Under basic conditions, MoO(3), UO(3), and KIO(4) can be reacted to form K(2)[UO(2)(MoO(4))(IO(3))(2)] (5), which is isostructural with 2 and 3. The structure of 1 consists of one-dimensional[UO(2)(CrO(4))(IO(3))(H(2)O)](-) ribbons that contain uranyl moieties bound by bridging chromate and iodate anions as well as a terminal water molecule to create [UO(7)] pentagonal bipyramidal environments around the U(VI) centers. These ribbons are separated from one another by Rb(+) cations. When the iodate content is increased in the hydrothermal reactions, the terminal water molecule is replaced by a monodentate iodate anion to yield 2-4. These ribbons can be further modified by replacing tetrahedral chromate anions with MoO(4)(2)(-) anions to yield isostructural, one-dimensional [UO(2)(MoO(4))(IO(3))(2)](2)(-) ribbons. Crystallographic data: 1, triclinic, space group P(-)1, a = 7.3133(5) A, b = 8.0561(6) A, c = 8.4870(6) A, alpha = 88.740(1) degrees, beta = 87.075(1) degrees, gamma = 71.672(1) degrees, Z = 2; 2, monoclinic, space group P2(1)/c, a = 11.1337(5) A, b = 7.2884(4) A, c = 15.5661(7) A, beta = 107.977(1) degrees, Z = 4; 3, monoclinic, space group P2(1)/c, a = 11.3463(6) A, b = 7.3263(4) A, c = 15.9332(8) A, beta = 108.173(1) degrees, Z = 4; 4, monoclinic, space group P2(1)/n, a = 7.3929(5) A, b = 8.1346(6) A, c = 22.126(2) A, beta = 90.647(1) degrees, Z = 4; 5, monoclinic, space group P2(1)/c, a = 11.3717(6) A, b = 7.2903(4) A, c = 15.7122(8) A, beta = 108.167(1) degrees, Z = 4.

Hydrothermal synthesis and crystal structure of Cs6[(UO2)4(W5O21)(OH)2(H2O)2]: a new polar uranyl tungstate

“…In particular, the incorporation of the oxoanions of elements with radioactive isotopes present in spent nuclear fuel [1], including 129 I [2][3][4][5][6][7], 181 W [8][9][10][11], 79 Se [12][13][14][15], and 93 Mo [16][17][18][19][20][21][22][23], into uranyl structures has gained focus. In this regard, a number of uranyl tungstates have been prepared in high-temperature solid-state reactions and display a rich structural chemistry because of variability in both the uranyl and tungsten coordination [8][9][10][11].…”

“…In known uranyl compounds, tungsten can have tetrahedral coordination as found in Na 10 [(UO 2 ) 8 [24,25]. The five-and six-coordinate modes for tungsten polyhedra that have been seen in uranyl compounds are illustrated in the structures of M 2 [(UO 2 )(W 2 O 8 )] (M=Li, Na, K, Ag) [8][9][10], M 2 [(UO 2 ) 2 (WO 5 )O] (M=K, Rb) [9], and Li 2 [(UO 2 ) 4 (WO 4 ) 4 O] [8]; coordination polyhedra of Mo(VI) show similarities to tungsten polyhedra and can also be four-, five-, or six-coordinate [16][17][18][19][20][21][22][23][24][25].…”

Recent advances on second-order NLO materials based on metal iodates

“…Reports on the metal chromium(VI) iodates are much fewer and no metal tungsten(VI) iodates has been reported so far. The A cations include alkali, alkaline earth, lanthanide(III), actinide, and silver(I) [106][107][108][109][110][111][112][113][114][115][116].…”

Hydrothermal synthesis and structure of K6[(UO2)4(CrO4)7]·6H2O: A layered uranyl chromate with a new uranyl sheet topology

“…[(CH 3 ) 4 7 [3], Ca 2 [(UO 2 ) 3 (PO 4 ) 2 (OH) 4 ] Á 4H 2 O [4], and Ni½ðUO 2 Þ 2 ðVO 4 Þ 2 Á 4H 2 O [5] are only a few of the U(VI) compounds containing tetrahedral oxoanions that have been either discovered as minerals, or produced synthetically. We have recently reported the hydrothermal preparation and structures of the mixed-metal uranyl iodates, Rb[UO 2 (CrO 4 )(IO 3 ) (H 2 O)] [6], A 2 ½UO 2 ðCrO 4 ÞðIO 3 Þ 2 (A ¼ K [6], Rb [6], Cs [6,7]), and K 2 ½UO 2 ðMoO 4 ÞðIO 3 Þ 2 [6], that also contain tetrahedral chromate or molybdate anions, respectively.…”