X-ray Structure Analysis Online 2010, VOL. 26 73 2010 © The Japan Society for Analytical Chemistry

X-ray Structure Analysis Online

Synthesis and Crystal Structure of (Cs3.5Rb0.5)[(Se0.85S0.15)O3]2[Te(OH)6]3

Manel DJEMEL,* Mohamed ABDELHEDI,*† Mohamed DAMMAK,* and Alain COUSSON**

*Laboratoire de Chimie Inorganique, Université de Sfax, Faculté des Sciences de Sfax, BP 1171, 3000 Sfax, Tunisia **Laboratoire Léon Brouillon, CEA/Saclay, 91191 Gif-Sur-Yvette Cedex, France

A mixed solution of (Cs3.5Rb0.5)[(Se0.85S0.15)O3]2[Te(OH)6]3 (CsRbSSeTe) was synthesized from an aqueous solution of H6TeO6, Rb2SO4, Rb2CO3, Cs2CO3, Cs2SO4 and H2SeO4. The rubidium sulfite selenite tellurate crystallizes in the orthorombic system with the Pccn space group. It was analyzed at room temperature using XRD data. The unit cell 3 3 parameters are a = 19.758(1), b = 9.464(1), c = 14.056(1)Å, Z = 8, V = 2628.22(2)Å , giving Dx = 3.63 g/cm . The refinement converged into R = 0.039, Rw = 0.040. The main feature of the atomic arrangements is the coexistence of 2– 2– 6– three and different anions (SO3 , SeO3 and TeO6 ) in the unit cell, connected by O–H·O hydrogen bonds, which allow construction of the crystal. The structures are formed by planes of octahedral Te(OH)6. Between these planes, we find 2– 2– + + mixed planes occupied by trigonal SO3 /SeO3 anions and Cs /Rb cations.

(Received April 10, 2010; Accepted August 2, 2010; Published on web November 10, 2010)

The telluric acid can form stable adducts with a large variety of In order to examine the effect of both partial anionic and organic and inorganic compounds of considerable importance, cationic substitution over the structural arrangements and the since Te(OH)6 acts as both an acceptor and a donor of hydrogen physical properties, we extended our research to a new mixed bonds. The alkaline sulfite and selenite compounds of the solid solution (Cs3.5Rb0.5)[(Se0.85S0.15)O3]2[Te(OH)6]3. general formula, M2XO3 with (M = Na, K and X = S, Se), have Crystals of CsRbSSeTe were prepared at room temperature by several crystallographic properties. The crystal structure of the slow evaporation of an aqueous solution. At the first step, 1 sodium selenite, Na2SeO3, was determined from X-ray powder we prepared a solution of Rb2SeO4 and Cs2SeO4 by mixing diffraction data. The structure consists of NaO6 octahedra and solutions of selenic acid H2SeO4 (Aldrich, 94%), caesium SeO3 pyramids, which are linked together through their edges. carbonate Cs2CO3 (Aldrich, 99.9%) and rubidium carbonate 2 The crystal structure of NiSeO3 can be described by the bc- Rb2CO3 (Aldrich, 99.8%). At the second step, we added to the plane with NiO6 octahedra arranged into two sub-groups. The found solution a solution of caesium , Cs2SO4 (Aldrich, 4+ lone pairs of Se occupy non-bonding regions of tunnels along 99.999%), and Rb2SO4 (Aldrich, 99.8%), and [001] and [010]. then a solution of telluric acid, H6TeO6 (Aldrich, 99%). Slow evaporation for several recrystallizations was necessary to obtain single crystals suitable to the X-ray diffraction study. After a

Table 1 Crystal and experimental data

Chemical formula (Cs3.5Rb0.5)[(Se0.85S0.15)O3]2[Te(OH)6]3 Formula weight (g mol–1) = 718.34 Crystal system: orthorhombic Space group: Pccn a = 19.758(1)Å b = 9.464(1)Å c = 14.056(1)Å V = 2628.22(2)Å3 Z = 8

2qmax˚ = 75.178 with Mo Ka T(K) = 293 –3 rmeas = 3.71. g cm –3 rcalc = 3.63 g cm Fig. 1 A part of the structure of (Cs3.5Rb0.5)[(Se0.85S0.15)O3]2[Te(OH) Data collection instrument: Kappa CCD 6]3, showing the asymmetric unit. Displacement ellipsoids are drawn Radiation, monochromator graphite l = 0.71073 Å at the 50% probability level. Measured reections: 6948 Unique reections: 1216 † To whom correspondence should be addressed. R = 0.039 and Rw = 0.040 E-mail: [email protected] CCDC deposition number: 421581 74 X-ray Structure Analysis Online 2010, VOL. 26 few days, transparent single crystals of CsRbSSeTe were obtained. Schematically the reaction is as follows:

2H2SeO4 + Cs2CO3 + Rb2CO3 æÆ Cs2SeO4 + Rb2SeO4 + 2CO2 + 2H2O

3H6TeO6 + 2x[y(Cs2SeO4) + (1 – y)(Rb2SeO4)] + 2(1 – x) [y(Cs2SO4) + (1 – y)(Rb2SO4)] æÆ (Csy Rb1–y)4 [(SexS1–x)O3]2[Te(OH)6]3 + O2

The chemical compositions obtained by an ICP-MS chemical analysis are 26.14, 32.50, 2.801, 9.24 and 0.5 wt% for Te, Cs, Rb, Se and S. This result leads to atomic ratios of 3.00:3.58:0.48:1.71:0.23 for Te:Cs:Rb:Se:S, which confirm the Fig. 2 A projection of the crystal structure of (Cs3.5Rb0.5)[(Se0.85S0.15) ratios in the structural formula, 3:3.5:0.5:1.7:0.3. O3]2[Te(OH)6]3 on the ac plane. –3 The density, Dm = 3.71 g cm , measured with the pycnometric method in CCl4 at room temperature, is in agreement with the –3 calculated value, Dcal = 3.63 g cm . The unit-cell dimensions were refined using X-ray diffraction data collected with a Kappa belonging to Te(1)O6 octahedral and six oxygen atoms

CCD Enraf Nonius diffractometor using Mo Ka radiation. The belonging to the Te(2)O6 octahedral. However the environment structure, (Cs3.5Rb0.5)[(Se0.85S0.15)O3]2[Te(OH)6]3, was analyzed of Cs/Rb(2) is made up of nine atoms belonging to the Te(1)O6 3 with the crystallographic CRYSTALS program. The structure octahedral and three oxygen atoms belonging to the Te(2)O6 was solved by conventional Patterson and difference-Fourier octahedral. The arrangement and the presence of different techniques. The chemical crystal data, the parameters used for anionic and cationic entities can be the origin of interesting X-ray diffraction data collection and strategy used for the crystal physical properties, such as ferroelectricity and protonic structure determination and their results, are listed in Table 1. conduction. Selected bond distances and angles are given in Table 2S We located geometrically the hydrogen atoms because the (supplemental). Structural graphics were created by the presence of the heavy atoms in this structures such as caesium, DIAMOND4 program. The asymmetric unit is shown in Fig. 1. rubidium, sulfure, selenium and tellure return the determination

The (Cs3.5Rb0.5)[(Se0.85S0.15)O3]2[Te(OH)6]3 (CsRbSSeTe) solid of the exact difficult position of these atoms. The CsRbSSeTe solution crystallizes in the orthorombic structure at room crystal structure is stable with O–H·O hydrogen bonds linking temperature. The main feature of this atomic arrangement is the the Te(OH)6 octahedral and SO3 and/or SeO3 trigonal groups. 2– 2– coexistence of three and different anions (SO3 , SeO3 and 6– TeO6 ) in the unit cell (Fig. 2). The structure is built by two kinds of Te(OH)6 planes. Between these planes, we find mixed Supplemental Materaials + + planes occupied by trigonal SO3/SeO3 and Cs /Rb cations. The Te atom in the (Cs3.5Rb0.5)[(Se0.85S0.15)O3]2[Te(OH)6]3 structure, Selected Bond distances and angles (Table 2S) was deposited as occupies two special positions. In consequence, the structure Supplemental Materials which is freely obtained from the shows two kinds of octahedral, Te(1)O6 and Te(2)O6. In fact, journal’s web page (http://www.jsac.or.jp/xraystruct/). the Te(1)–O distances, in the Te(1)O6 groups, are between 1.879(12) and 1.951(12)Å and the O–Te(1)–O angle values vary from 86.8(6)˚ and 93.8(7)˚ (Table 2S). However these distances References in Te(2)O6 groups vary from 1.898(14) and 1.944(11)Å with O– Te(2)–O angle values of between 85.7(10)˚ and 93.3(6)˚. 1. R. B. Helmholdt, E. J. Sonneveld, and H. Schenk, Z.

The S/Se–O distances in the (Cs3.5Rb0.5)[(Se0.85S0.15)O3]2- Kristallog., 1999, 151. [Te(OH)6]3 compound vary from 1.688(12) to 1.737(12)Å. In 2. M. Miljak, R. Becker, M. Herak, M. Prester, O. Milat, M. the trigonal groups, the O–Se/S–O angle values in CsRbSSeTe Johnsson, and H. Berger, J. Phys. Condensed Matter, 2007, are between 101.3(6) and 102.6(5)˚. These distances and angles 19, 196203.1. values are similar to those observed in the structures of Na2SO3 3. Betteridge, P. W. Carruthers, J. R. Cooper, R. I. Prout, and 2 (ref. 1) and NiSeO3 (ref. 2). K. Watkin, J. Appl. Cryst., 2003, E36, 1487. The Rb/Cs atoms are distributed on two sites. The two cations 4. K. Brandenburg, M. Berndt, DIAMOND. Crystal Impact are coordinated by twelve oxygen atoms. In fact, the Gb R, Bonn, Germany, 1999, Version 2.1.b. environment of Cs/Rb(1) is made up of six oxygen atoms