Cation Size Effect on the Framework Structures in a Series of New Alkali-Metal Indium Selenites, AIn(SeO₃)₂ (A = Na, K, Rb, and Cs)

Abstract

A new family of quaternary alkali-metal indium selenites, AIn(SeO(3))(2) (A = Na, K, Rb, and Cs) have been synthesized, as crystals and pure polycrystalline phases through standard solid-state and hydrothermal reactions. The structures of the reported materials have been determined by single-crystal X-ray diffraction. While AIn(SeO(3))(2) (A = Na, K, and Rb) crystallize in the orthorhombic space group, Pnma, with three-dimensional framework structures, CsIn(SeO(3))(2) crystallizes in the trigonal space group, R3m, with a two-dimensional structure. All of the reported materials, however, share a common structural motif, a network of corner-shared InO(6) octahedra and SeO(3) groups. Interestingly, the size of the alkali-metal cations profoundly influences the bonding nature of the SeO(3) group to the InO(6) octahedra. Complete characterizations including infrared spectroscopy, elemental analyses, and thermal analyses for the compounds are also presented, as are dipole moment calculations. A detailed cation size effect on the framework structure is discussed.

Li13Mn(SeO3)8: Lithium-Rich Transition Metal Selenite Containing Jahn–Teller Distortive Cations

“…Because the Se 4+ cation contains a stereoactive lone pair, the extent of asymmetric environment can be understood by calculating the local dipole moments. − The determined dipole moments for the asymmetric SeO 3 polyhedra range from 7.9 to 9.6 debye (D), which are consistent with those for previously reported selenites (see Table ). ,− ,− ,, …”

“…52−54 The determined dipole moments for the asymmetric SeO 3 polyhedra range from 7.9 to 9.6 debye (D), which are consistent with those for previously reported selenites (see Table 2). 18,[22][23][24][25][26][27][29][30][31][32]34,41 Thermal analyses indicate that Li 13 Sc(SeO 3 ) 8 , Li 13 Cr(SeO 3 ) 8 , Li 13 Mn(SeO 3 ) 8 , and Li 13 Fe(SeO 3 ) 8 are thermally stable up to 620, 570, 500, and 540 °C, respectively. Above the temperatures, each material decomposes perhaps attributed to the volatilization of SeO 2 at higher temperatures.…”

“…The excellent reactivity of SeO 2 with a variety of other metal cations resulted in a number of novel selenites exhibiting fascinating physicochemical characteristics such as magnetic properties − and water-oxidation catalysis . In addition, the asymmetric coordination environment of Se 4+ attributed to the stereochemically active lone pair often induced the solid state compounds to crystallize in macroscopic noncentrosymmetric (NCS) space groups, which subsequently revealed very interesting second-order nonlinear optical (NLO) properties. − The overall centricity and the framework structures have been successfully controlled by the size of the constituted cations. − Moreover, rich structural chemistry with variable structural dimensions has been demonstrated in many mixed metal selenites by introducing a variety of polyhedra of other metal cations during the syntheses. − We have investigated a system containing lithium transition metal selenites in order to expand the selenite chemistry further. Thus far, several lithium containing selenite materials exhibiting captivating properties have been reported. ,− For example, Li 5 Mn 2 (SeO 3 ) 8 and LiFe­(SeO 3 ) contain magnetic ions in their extended backbones, polar Li 6 (Mo 2 O 5 ) 3 (SeO 3 ) 6 exhibits strong second-harmonic generation (SHG) properties, and LiSc­(SeO 3 ) 2 · x H 2 O shows extremely high temperature single-crystal to single-crystal transformation reactions.…”

Toward the Rational Design of Novel Noncentrosymmetric Materials: Factors Influencing the Framework Structures

“…A common structural motif, a network of cornershared InO 6 octahedra and SeO 3 trigonal pyramids, is observed in the family (Figure 5). 43 However, while AIn(SeO 3 ) 2 (A = Na, K, Rb) have a three-dimensional framework structure, CsIn(SeO 3 ) 2 exhibits a two-dimensional structure. As shown in Figure 5, similar channel structures constructed by corner sharing of InO 6 octahedra and SeO 3 polyhedra are observed in the family.…”

Syntheses, crystal structures of a series of novel alkali metal or alkaline earth metal phosphites

“…166), and CsIn(HPO 3 ) 2 is isomorphous with CsInSe 2 O 6 . 39 The asymmetric unit of RbIn(HPO 3 ) 2 contains one Rb, one In, and two phosphite anions, all of them at general sites (Fig. 2a).…”