Mild Periodic Acid Flux and Hydrothermal Methods for the Synthesis of Crystalline f-Element-Bearing Iodate Compounds

Abstract

f-element-bearing iodate compounds are a large family mostly synthesized by hydrothermal reactions starting with actinide/lanthanide ions and iodic acid or iodate salt. In this work, we introduce melting periodic acid flux as a new reaction medium and provide a safe way for single-crystal growth of a series of new f-element iodate compounds including UO(IO)·HO (1), UO(IO)(HO)·HIO (2), α-Th(IO)(NO)(OH) (3), β-Th(IO)(NO)(OH) (4), and (HO)Nd(IO)·3HIO (5). The structures of these compounds deviate from those afforded from hydrothermal reactions. Specifically, compounds 1 and 2 exhibit pillared structures consisting of uranyl pentagonal bipyramids and iodate trigonal pyramids. Compounds 3 and 4 represent two new thorium iodate compounds that are constructed from subunits of thorium dimers. Compound 5 exhibits a flower-shaped trivalent lanthanide iodate structure with HIO molecules and HO cations filled in the channels. The aliovalent replacement of f elements in 5 is available from a hydrothermal process, further generating compounds of Th(IO)(HO) (6) and Ce(IO)(HO) (7). The distinct absorption features are observed in isotypic compounds 5-7, where 7 shows typical semiconductor behavior with a band gap of 2.43 eV. Remarkably, noncentrosymmetric 1, 6, and 7 exhibit strong second-harmonic-generation efficiencies of 1.3, 3.2, and 9.2 times, respectively, that of the commercial material KHPO. Additionally, the temperature-dependent emission spectra of 1 and 2 were also collected showing typical emission features of uranyl units and a negative correlation between the intensities of the emissions with temperature. Clearly, the presented low-temperature melting inorganic acid flux synthesis would provide a facile and effective strategy to produce a large new family of structurally versatile and multifunctional f-element inorganic compounds.

REI5O14 (RE=Y and Gd): Promising SHG Materials Featuring the Semicircle‐Shaped I5O143− Polyiodate Anion

“…IR spectra revealed that REI 5 O 14 (RE=Y and Gd) are transparent from 2.5–11.3 μm (4000–885 cm −1 ), (Figure S8), and in Table S5 the absorption peaks were assigned in detail . The maximum IR transparent ranges are 13.6, 12.5, and 12.1 μm for RbIO 3 , NaI 3 O 8 , and CsI 4 O 11 , respectively .…”

Ce(IO3)2F2⋅H2O: The First Rare‐Earth‐Metal Iodate Fluoride with Large Second Harmonic Generation Response

“…Moreover, rare earth iodates have very complex structural chemistry and arouse great attention in searching for novel materials with interesting optical properties, especially nonlinear optical (NLO) and luminescent properties . Consequently, a series of rare earth metal iodates, RE(MoO 2 )(IO 3 ) 4 (OH) (RE=Nd, Sm, Eu), α‐Ln(IO 3 ) 3 (Ln=Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu), Sm(IO 3 ) 3 ⋅2 H 2 O, as well as some cerium iodates, such as Ce(IO 3 ) 3 , Ce 2 (IO 3 ) 8 (H 2 O), Ce 2 I 6 O 18 , and K 8 Ce 2 I 18 O 53 , have been reported. Up to now, no fluorine‐containing rare earth metal iodates have been reported.…”

“…In the structure, CeO 5 F 4 polyhedra connect with isolated IO 3 groupst of orm 1D infinite 1 1 [Ce(IO 3 ) 2 F 2 ]c hains, which interconnect with each other by weak hydrogenb onds to construct the whole structure. [20] Consequently, as eries of rare earth metal iodates,R E(MoO 2 )(IO 3 ) 4 (OH) (RE = Nd, Sm, Eu), [21] a-Ln(IO 3 ) 3 (Ln = Y, Pr,N d, Sm, Eu, Gd, Tb, Dy,H o, Er,Y b, Lu), [19b] Sm(IO 3 ) 3 ·2 H 2 O, [22] as well as some cerium iodates, such as Ce(IO 3 ) 3 , [23] Ce 2 (IO 3 ) 8 (H 2 O), [24] Ce 2 I 6 O 18 , [25] and K 8 Ce 2 I 18 O 53 , [26] have been reported. Theoreticalc alculations with DFTand dipole moments were performed to illustrate the relationshipsb etween the structurea nd the properties.T he resultss how that Ce(IO 3 ) 2 F 2 ·H 2 Oi sanew iodate fluoride with novel structure and potentiala pplications in nonlinearoptics.…”

“…[17] To the best of our knowledge,o nly the above three metal iodate fluorides have been reported.T he electronic clouds in the (IO 3 ) À anion are more polarizable than those in the (IO 2 F 2 ) À anion or other IO/F units; [18] for example, the SHG responseo fR b(IO 2 F 2 )i s muchs maller than that of Rb(IO 3 ). [20] Consequently, as eries of rare earth metal iodates,R E(MoO 2 )(IO 3 ) 4 (OH) (RE = Nd, Sm, Eu), [21] a-Ln(IO 3 ) 3 (Ln = Y, Pr,N d, Sm, Eu, Gd, Tb, Dy,H o, Er,Y b, Lu), [19b] Sm(IO 3 ) 3 ·2 H 2 O, [22] as well as some cerium iodates, such as Ce(IO 3 ) 3 , [23] Ce 2 (IO 3 ) 8 (H 2 O), [24] Ce 2 I 6 O 18 , [25] and K 8 Ce 2 I 18 O 53 , [26] have been reported. [20] Consequently, as eries of rare earth metal iodates,R E(MoO 2 )(IO 3 ) 4 (OH) (RE = Nd, Sm, Eu), [21] a-Ln(IO 3 ) 3 (Ln = Y, Pr,N d, Sm, Eu, Gd, Tb, Dy,H o, Er,Y b, Lu), [19b] Sm(IO 3 ) 3 ·2 H 2 O, [22] as well as some cerium iodates, such as Ce(IO 3 ) 3 , [23] Ce 2 (IO 3 ) 8 (H 2 O), [24] Ce 2 I 6 O 18 , [25] and K 8 Ce 2 I 18 O 53 , [26] have been reported.…”

Observation of the Same New Sheet Topology in Both the Layered Uranyl Oxide-Phosphate Cs11[(UO2)12(PO4)3O13] and the Layered Uranyl Oxyfluoride-Phosphate Rb11[(UO2)12(PO4)3O12F2] Prepared by Flux Crystal Growth

“…The uranophane topology is specifically prominent among silicates, but as in the phosphuranylite topology the tetrahedrally coordinated Si or P sites can be replaced by other tetrahedrally—or even trigonal pyramidal or trigonal planar—coordinating elements. These sheet anion-topologies common among minerals have also been observed in numerous synthetic compounds including 38 belonging to the autunite, 18 belonging to the uranophane, and 16 belonging to the phosphuranylite classes (Lussier et al, 2016; Wang et al, 2017; Juillerat et al, 2018a;Juillerat and zur Loye, 2019).…”