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The ambient-temperature form of dithallium sulfate, β-Tl2SO4, is similar to β-K2SO4 and is characterized by isolated sulfate tetrahedra and two different thallium sites with coordination numbers 9 and 11. All the atoms, except one O atom, lie on mirror planes. In spite of there being a high concentration of Tl+ cations, the stereochemical activity of the 6s2 pairs is low, similar to that of isotypic Tl2XO4 compounds (X = Cr and Se). This behaviour is the consequence of both weak Tl—O bonds and strong X—O bonds, because in a Tl—O—X linkage the electronic cloud of the O2− anion is strongly distorted and displaced towards X, resulting in a low negative charge in the face of the Tl atom. Consequently, the Coulombic repulsions between the lone pair and the O2− anions are weak. All of the Tl2XO4 compounds exhibit the same open packing of A+ cations and [XO4]2− anions as their isotypic alkali counterparts.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104022346/iz1045sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104022346/iz1045Isup2.hkl
Contains datablock I

Comment top

Heavy Mm+ p-block cations with the electron configuration ns2 np0 may show stereochemical activity of the ns2 pair that results in a very asymmetric anionic environment. It is commonly believed that this activity is stronger when the concentration of Mm+ cations is high (Marchand et al., 1975; Verbaere et al., 1978; Jouini, 1986), especially for compounds of the Tl/X/O system, with a Tl/X ratio greater than or equal to 2 (Jouanneaux et al., 1991). An ideal example can be found in Tl2SO4, with a Tl/S ratio of 2 and a high specific volume per oxygen anion (VOx = 30.83 Å3; Pannetier & Gaultier, 1966a), similar to other compounds of thallium with tetrahedral oxyanions, e.g. Tl3Li(MoO4)2 and Tl3Li(WO4)2, which muster strong activity of the Tl+ 6 s2 lone pair (Colbeau-Justin et al., 1997). However, the crystal structure of β-Tl2SO4 (low-temperature form) shows nearly regular TlOn polyhedra, accounting for its low stereochemical activity (Pannetier & Gaultier, 1966b). Furthermore, in a comparative study of isotypical Tl2XO4 compounds (X = Cr, S and Se), the oxygen framework of β-Tl2SO4 was quite different from those of the analogous compounds (Fabry & Breczewski, 1993). It should be noted, however, that the structure of β-Tl2SO4 is the least reliably determined among this family. More recently, the structural instability of the Tl2XO4 compounds (X = Cr, Mo, W, S and Se) were studied (Friese et al., 2004), relying on the only structural model published to this date for β-Tl2SO4 (Pannetier & Gaultier, 1966b). As the accuracy of the paper cited does not meet today's standards, we decided to redetermine the crystal structure of β-Tl2SO4 to gain a better basis for stereochemical discussion. Previous crystallographic studies of Tl2XO4 compounds have established that they are isotypic with their potassium counterparts (Fischmeister, 1962; McGinnety, 1972; Carter & Margulis, 1972; Fabry & Breczewski, 1993). The present study confirms the isostructural relationship between β-Tl2SO4 and β-K2SO4 (orthorhombic, space group Pnma, Z = 4). The refinement of the atomic coordinates was performed from previously published data (Pannetier & Gaultier, 1966b). The final values show: (i) an accuracy gain of a magnitude, compared with previous work; (ii) a better reliability factor (RF = 0.025 instead of 0.117); (iii) noticeable differences in some coordinates of the O atoms; and (iv) lower and more realistic displacement parameters.

All the atoms, except atom O3, lie on mirror planes. Consequently all the anionic polyhedra have crystallographically imposed m symmetry. The structure is made up of independent SO4 tetrahedra, with one pseudo-threefold axis aligned almost parallel or antiparallel to the a axis (Fig. 1). The two distinct thallium cations provide the electrostatic cohesion between the anionic entities. Using bond-valence parameters (Brese & O'Keeffe, 1991), the coordination numbers for atoms Tl1 and Tl2 are found to be, respectively, 11 and 9. Around each Tl atom there is one very close and four close O-atom neighbours (Table 1), similar to the isotypic Tl2SeO4 (Fabry & Breczewski, 1993) and Tl2CrO4 (Carter & Margulis, 1972) compounds. For each Tl atom, the strongest Tl—O bond (nearly 2.8 Å) is far shorter than the sum of the ionic radii (3.05 Å; Shannon, 1976). Furthermore, the sum of the bond strengths around atom Tl1 appears much lower than 1 valence unit (Table 2). Therefore, in order to estimate the stereochemical effect of the Tl+ cations, we used a simple method based on an electrostatic approach (Verbaere et al., 1978). The Tl+ cation is treated as a Tl3+–E2− dipole (where E2− stands for the lone pair) interacting with the local electrostatic field ε, dominated by the coordinating anions. Assuming that the high polarizability of thallium(I) (α = 7.28 Å3; Shannon, 1993) arises mainly from the ability of the s2 orbital to hybridize, we used the following relation: 2 e·Tl–E = αε. The ions were treated as point charges, with values derived from the ionicities of the bonds according to a recent model (Guo et al., 1999), viz. +0.72 for atom Tl, +1.75 for the S atom and −0.78 for the O atoms. The program HYBRIDE (Wallez, 1999), based on Ewald's method, was run by loops until reaching the self-consistent position of the lone pair E. The two Tl—E distances obtained for β-Tl2SO4 are short and account for the low stereochemical activity, although the activity is? higher for atom Tl1, at variance with previous results (Table 2). For symmetry reasons, each lone pair E is constrained to the same mirror plane as the corresponding Tl atom. The dipole vectors are aligned roughly parallel to [100], and for atom Tl1 the activity is enough to push away the five shortest Tl—-O bonds (Fig. 2). A comparison can be made with other oxygen compounds of thallium(I), for which active lone pairs are generally found to be 0.4–0.7 Å distant from the bearer, with correlatively shorter Tl—O bonds (2.38–2.69 Å; El Abiad et al., 2000; Lafjij et al., 2003), close to the sum of the ionic radii of the Tl3+ and O2− ions (2.4 Å; Shannon, 1976). Our results show that β-Tl2SO4 is structurally comparable to isotypic Tl2CrO4 (Carter & Margulis, 1972) and Tl2SeO4 (Fabry & Breczewski, 1993). It is, however, surprising to observe such a low stereochemical activity of the lone pair, considering that the following two conditions are fulfilled:

(i) A Tl/S ratio of 2. In the Tl/X/O systems (X=B, C, Si, Ti, Sn, P and Sb), the 6 s2 lone pair exhibits a stereochemical activity that ensures structural cohesion when the ratio is greater than or equal to 2 (Jouanneaux et al., 1991);

(ii) A high specific volume per O atom (VOx = volume of the unit cell/number of O atoms in the unit cell). The stereochemical activity of a lone pair often results in a supplementary bulk that can be compared with that of an O2− anion (Galy et al., 1975). In the present case, VOx = 30.82 Å3, and if considering each lone pair as an additional O atom, VOx,E = 20.55 Å3, which is a value commonly observed within compact oxygen frameworks (Galy et al., 1975).

This result should not be seen as an anomaly but as an effect of the very nature of the Tl+ ion (a large and low-charge cation) and of the S—O bond (strong and covalent). In a Tl—O—S linkage, the electronic cloud of the O2− anion is strongly distorted and displaced toward the S atom, resulting in a low negative charge in the vicinity? of the Tl atom. Therefore, the Tl+ cation is coordinated via weak bonds to a high number of low-charge anions that generate a low electrostatic field on the cation site, which is unlikely to stimulate the stereochemical activity of the 6 s2 pair. All Tl2XO4 compounds of β-K2SO4 type, that is, hosting a small tetracoordinated XVI cation (X = S, Se and Cr; Friese et al., 2004) show a similar behaviour. In order to generalize to the A2XO4 isotypes, we have plotted the volume of the crystal cell (from the JCPDS files) as a function of rA+3 (Fig. 3). The corresponding VOx values, ranging from 21.7 (Na2SO4) to 38.1 Å3 (Cs2SeO4), appear particularly high and indicate an open packing of the A+ cations and [XO4]2− oxyanions. Otherwise, the volume evolution appears almost linear with cation volume, and the Tl+ ion does not seem to behave differently from an alkali cation. Therefore, in contrast to the predictive criteria (high Tl/X ratio and VOx > 25 Å3), the stereochemical activity of the Tl+ 6 s2 pair cannot be anything but low, at variance with the behaviour of isoelectronic cations of higher oxidation states (Pb2+ and Bi3+).

To summarize, the criteria Tl/X>2 and high VOx are not really predictive of a strong activity of the 6 s2 pair of the Tl+ ion in oxygen compounds. The activity will be stronger if the anions of the coordination polyhedron exert a strong and directional Coulombic repulsion on the 6 s2 pair. For this purpose, the anions must generate a strong field by being (i) in a reduced number around atom Tl in order to form a small and irregular coordination polyhedron, and (ii) strongly bound to Tl, and bearing high real charges. Because none of these conditions are fulfilled in the Tl2XO4 compounds, the faint stereochemical activity of the 6 s2 pair is quite understandable.

Experimental top

Crystals of β-Tl2SO4 were grown from an aqueous solution of commercial product (Aldrich, 99.99% purity) evaporated slowly at room temperature. The crystals appear as colourless acicular polyhedra.

Computing details top

Data collection: reference?; cell refinement: reference?; data reduction: reference?; program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. A ce l l projection along the a axis, showing the Tl atoms (circles) and SO4 tetrahedra pointing up or down.
[Figure 2] Fig. 2. A view of the Tl-atom environments (only the five nearest O atoms are shown), with 50% probability displacement ellipsoids and localization of the lone pairs. The projection plane is nearly the mirror plane. For clarity, the Tl—E distances (arrows) have been multiplied by a factor of 5.
[Figure 3] Fig. 3. Unit-cell volumes of A2XO4 isotypic compouds (A = Na, K, Tl, Rb and Cs, and X = S, Cr and Se) as a function of (ionic radius of the A+ cations)3.
dithallium sulfate top
Crystal data top
Tl2SO4F(000) = 840
Mr = 504.80Dx = 6.800 Mg m3
Dm = 6.75 (7) Mg m3
Dm measured by picnometry
Orthorhombic, PnmaMo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ac 2nCell parameters from 21 reflections
a = 7.818 (1) Åθ = 8.7–12.1°
b = 5.931 (1) ŵ = 65.60 mm1
c = 10.634 (2) ÅT = 293 K
V = 493.08 (14) Å3Needle, colourless
Z = 40.11 × 0.04 × 0.02 mm
Data collection top
Syntex Nicolet P3F
diffractometer
571 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.000
Graphite monochromatorθmax = 27.5°, θmin = 3.2°
θ/2θ scansh = 010
Absorption correction: analytical
(de Meulenaer & Tompa, 1965)
k = 07
Tmin = 0.074, Tmax = 0.356l = 013
605 measured reflections3 standard reflections every 60 reflections
605 independent reflections intensity decay: 1.1%
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.025 w = 1/[s2(Fo2) + ( 0.048P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.064(Δ/σ)max < 0.001
S = 1.04Δρmax = 1.60 e Å3
605 reflectionsΔρmin = 1.58 e Å3
41 parametersExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2l3/sin(2q)]-1/4
0 restraintsExtinction coefficient: 0.0136 (7)
Crystal data top
Tl2SO4V = 493.08 (14) Å3
Mr = 504.80Z = 4
Orthorhombic, PnmaMo Kα radiation
a = 7.818 (1) ŵ = 65.60 mm1
b = 5.931 (1) ÅT = 293 K
c = 10.634 (2) Å0.11 × 0.04 × 0.02 mm
Data collection top
Syntex Nicolet P3F
diffractometer
571 reflections with I > 2σ(I)
Absorption correction: analytical
(de Meulenaer & Tompa, 1965)
Rint = 0.000
Tmin = 0.074, Tmax = 0.3563 standard reflections every 60 reflections
605 measured reflections intensity decay: 1.1%
605 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.02541 parameters
wR(F2) = 0.0640 restraints
S = 1.04Δρmax = 1.60 e Å3
605 reflectionsΔρmin = 1.58 e Å3
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement on F2 for ALL reflections except for 0 with very negative F2 or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating _R_factor_obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Tl10.67125 (5)0.25000.41154 (4)0.0324 (2)
Tl20.99330 (5)0.25000.70400 (4)0.0318 (2)
S0.2242 (3)0.25000.4202 (2)0.0199 (5)
O10.0349 (14)0.25000.4168 (11)0.050 (3)
O20.2843 (11)0.25000.5503 (9)0.040 (2)
O30.2905 (8)0.0470 (11)0.3584 (8)0.049 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Tl10.0258 (3)0.0286 (3)0.0427 (3)0.0000.0032 (2)0.000
Tl20.0210 (3)0.0360 (3)0.0384 (3)0.0000.0001 (2)0.000
S0.0118 (9)0.0215 (11)0.0265 (12)0.0000.0016 (8)0.000
O10.044 (5)0.048 (6)0.060 (7)0.0000.004 (5)0.000
O20.035 (4)0.053 (5)0.032 (4)0.0000.015 (4)0.000
O30.038 (3)0.037 (3)0.073 (5)0.006 (3)0.009 (3)0.019 (4)
Geometric parameters (Å, º) top
Tl1—O1i2.843 (11)S—O3vii1.467 (6)
Tl1—O2ii3.013 (2)S—O31.467 (6)
Tl1—O2iii3.013 (2)S—O11.480 (11)
Tl1—O3iv3.029 (9)O1—O22.411 (15)
Tl1—O3iii3.029 (9)O1—O32.415 (11)
Tl1—O3v3.250 (9)O1—O3vii2.415 (11)
Tl1—O3vi3.250 (9)O1—Tl1xiii2.843 (11)
Tl1—O3vii3.260 (7)O1—Tl2xiii3.071 (12)
Tl1—O33.260 (7)O1—Tl2ii3.239 (5)
Tl1—O23.366 (8)O1—Tl2iii3.239 (5)
Tl1—O1v3.651 (12)O1—O1xiv3.496 (13)
Tl1—Tl2viii3.9141 (6)O1—O1xv3.496 (13)
Tl2—O2i2.801 (8)O1—Tl1xvi3.651 (12)
Tl2—O3iv2.910 (7)O2—O3vii2.369 (11)
Tl2—O3iii2.910 (7)O2—O32.369 (11)
Tl2—O3ix2.942 (6)O2—Tl2xiii2.801 (8)
Tl2—O3x2.942 (6)O2—Tl1ii3.013 (2)
Tl2—O1i3.071 (12)O2—Tl1iii3.013 (2)
Tl2—O2xi3.082 (10)O2—Tl2xvii3.082 (10)
Tl2—O1ii3.239 (5)O3—O3vii2.408 (13)
Tl2—O1iii3.239 (5)O3—Tl2iii2.910 (7)
Tl2—Tl1ix3.9141 (6)O3—Tl2xviii2.942 (6)
Tl2—Tl1xii3.9141 (6)O3—Tl1iii3.029 (9)
S—O21.461 (10)O3—Tl1xvi3.250 (9)
O1i—Tl1—O2ii83.2 (2)O2—S—O3108.1 (4)
O1i—Tl1—O2iii83.2 (2)O3vii—S—O3110.4 (6)
O2ii—Tl1—O2iii159.6 (4)O2—S—O1110.2 (6)
O1i—Tl1—O3iv83.4 (2)O3vii—S—O1110.0 (4)
O2ii—Tl1—O3iv46.2 (2)O3—S—O1110.0 (4)
O2iii—Tl1—O3iv116.9 (2)S—O1—O234.7 (4)
O1i—Tl1—O3iii83.4 (2)S—O1—O334.8 (3)
O2ii—Tl1—O3iii116.9 (2)O2—O1—O358.8 (4)
O2iii—Tl1—O3iii46.2 (2)S—O1—O3vii34.8 (3)
O3iv—Tl1—O3iii71.1 (3)O2—O1—O3vii58.8 (4)
O1i—Tl1—O3v74.4 (2)O3—O1—O3vii59.8 (4)
O2ii—Tl1—O3v73.8 (2)S—O1—Tl1xiii179.7 (7)
O2iii—Tl1—O3v116.8 (2)O2—O1—Tl1xiii145.1 (5)
O3iv—Tl1—O3v118.01 (3)O3—O1—Tl1xiii145.3 (3)
O3iii—Tl1—O3v154.23 (11)O3vii—O1—Tl1xiii145.3 (3)
O1i—Tl1—O3vi74.4 (2)S—O1—Tl2xiii94.7 (5)
O2ii—Tl1—O3vi116.8 (2)O2—O1—Tl2xiii60.0 (3)
O2iii—Tl1—O3vi73.8 (2)O3—O1—Tl2xiii110.1 (4)
O3iv—Tl1—O3vi154.23 (11)O3vii—O1—Tl2xiii110.1 (4)
O3iii—Tl1—O3vi118.01 (3)Tl1xiii—O1—Tl2xiii85.1 (3)
O3v—Tl1—O3vi43.5 (2)S—O1—Tl2ii94.5 (3)
O1i—Tl1—O3vii156.38 (14)O2—O1—Tl2ii106.8 (2)
O2ii—Tl1—O3vii76.4 (2)O3—O1—Tl2ii114.3 (4)
O2iii—Tl1—O3vii119.5 (2)O3vii—O1—Tl2ii59.9 (2)
O3iv—Tl1—O3vii90.9 (2)Tl1xiii—O1—Tl2ii85.6 (2)
O3iii—Tl1—O3vii116.41 (13)Tl2xiii—O1—Tl2ii112.8 (2)
O3v—Tl1—O3vii88.4 (2)S—O1—Tl2iii94.5 (3)
O3vi—Tl1—O3vii104.23 (15)O2—O1—Tl2iii106.8 (2)
O1i—Tl1—O3156.38 (14)O3—O1—Tl2iii59.9 (2)
O2ii—Tl1—O3119.5 (2)O3vii—O1—Tl2iii114.3 (4)
O2iii—Tl1—O376.4 (2)Tl1xiii—O1—Tl2iii85.6 (2)
O3iv—Tl1—O3116.41 (13)Tl2xiii—O1—Tl2iii112.8 (2)
O3iii—Tl1—O390.9 (2)Tl2ii—O1—Tl2iii132.5 (4)
O3v—Tl1—O3104.23 (15)S—O1—O1xiv98.3 (4)
O3vi—Tl1—O388.4 (2)O2—O1—O1xiv80.1 (4)
O3vii—Tl1—O343.4 (2)O3—O1—O1xiv133.0 (5)
O1i—Tl1—O2152.9 (3)O3vii—O1—O1xiv80.6 (3)
O2ii—Tl1—O292.6 (2)Tl1xiii—O1—O1xiv81.6 (4)
O2iii—Tl1—O292.6 (2)Tl2xiii—O1—O1xiv58.7 (3)
O3iv—Tl1—O274.6 (2)Tl2ii—O1—O1xiv54.09 (14)
O3iii—Tl1—O274.6 (2)Tl2iii—O1—O1xiv165.2 (5)
O3v—Tl1—O2130.2 (2)S—O1—O1xv98.3 (4)
O3vi—Tl1—O2130.2 (2)O2—O1—O1xv80.1 (4)
O3vii—Tl1—O241.9 (2)O3—O1—O1xv80.6 (3)
O3—Tl1—O241.9 (2)O3vii—O1—O1xv133.0 (5)
O1i—Tl1—O1v108.1 (3)Tl1xiii—O1—O1xv81.6 (4)
O2ii—Tl1—O1v99.4 (2)Tl2xiii—O1—O1xv58.7 (3)
O2iii—Tl1—O1v99.4 (2)Tl2ii—O1—O1xv165.2 (5)
O3iv—Tl1—O1v143.24 (14)Tl2iii—O1—O1xv54.09 (14)
O3iii—Tl1—O1v143.24 (14)O1xiv—O1—O1xv116.0 (7)
O3v—Tl1—O1v40.4 (2)S—O1—Tl1xvi74.4 (5)
O3vi—Tl1—O1v40.4 (2)O2—O1—Tl1xvi109.1 (4)
O3vii—Tl1—O1v64.4 (2)O3—O1—Tl1xvi60.8 (3)
O3—Tl1—O1v64.4 (2)O3vii—O1—Tl1xvi60.8 (3)
O2—Tl1—O1v99.0 (2)Tl1xiii—O1—Tl1xvi105.8 (3)
O1i—Tl1—Tl2viii109.86 (14)Tl2xiii—O1—Tl1xvi169.1 (4)
O2ii—Tl1—Tl2viii50.8 (2)Tl2ii—O1—Tl1xvi68.9 (2)
O2iii—Tl1—Tl2viii149.3 (2)Tl2iii—O1—Tl1xvi68.9 (2)
O3iv—Tl1—Tl2viii92.71 (13)O1xiv—O1—Tl1xvi122.0 (3)
O3iii—Tl1—Tl2viii158.18 (12)O1xv—O1—Tl1xvi122.0 (3)
O3v—Tl1—Tl2viii46.80 (12)S—O2—O3vii36.0 (2)
O3vi—Tl1—Tl2viii82.93 (11)S—O2—O336.0 (2)
O3vii—Tl1—Tl2viii47.34 (12)O3vii—O2—O361.1 (4)
O3—Tl1—Tl2viii83.23 (14)S—O2—O135.2 (4)
O2—Tl1—Tl2viii87.23 (11)O3vii—O2—O160.7 (4)
O1v—Tl1—Tl2viii50.56 (3)O3—O2—O160.7 (4)
O2i—Tl2—O3iv119.1 (2)S—O2—Tl2xiii106.9 (5)
O2i—Tl2—O3iii119.1 (2)O3vii—O2—Tl2xiii121.3 (4)
O3iv—Tl2—O3iii74.5 (3)O3—O2—Tl2xiii121.3 (4)
O2i—Tl2—O3ix81.9 (2)O1—O2—Tl2xiii71.8 (4)
O3iv—Tl2—O3ix101.7 (2)S—O2—Tl1ii99.5 (2)
O3iii—Tl2—O3ix158.10 (12)O3vii—O2—Tl1ii67.3 (2)
O2i—Tl2—O3x81.9 (2)O3—O2—Tl1ii127.9 (3)
O3iv—Tl2—O3x158.10 (12)O1—O2—Tl1ii99.9 (2)
O3iii—Tl2—O3x101.7 (2)Tl2xiii—O2—Tl1ii90.9 (2)
O3ix—Tl2—O3x73.5 (3)S—O2—Tl1iii99.5 (2)
O2i—Tl2—O1i48.2 (3)O3vii—O2—Tl1iii127.9 (3)
O3iv—Tl2—O1i81.6 (2)O3—O2—Tl1iii67.3 (2)
O3iii—Tl2—O1i81.6 (2)O1—O2—Tl1iii99.9 (2)
O3ix—Tl2—O1i119.6 (2)Tl2xiii—O2—Tl1iii90.9 (2)
O3x—Tl2—O1i119.6 (2)Tl1ii—O2—Tl1iii159.6 (4)
O2i—Tl2—O2xi157.7 (3)S—O2—Tl2xvii166.7 (5)
O3iv—Tl2—O2xi77.8 (2)O3vii—O2—Tl2xvii136.0 (3)
O3iii—Tl2—O2xi77.8 (2)O3—O2—Tl2xvii136.0 (3)
O3ix—Tl2—O2xi80.3 (2)O1—O2—Tl2xvii158.1 (4)
O3x—Tl2—O2xi80.3 (2)Tl2xiii—O2—Tl2xvii86.3 (2)
O1i—Tl2—O2xi154.1 (2)Tl1ii—O2—Tl2xvii79.9 (2)
O2i—Tl2—O1ii79.9 (2)Tl1iii—O2—Tl2xvii79.9 (2)
O3iv—Tl2—O1ii45.9 (2)S—O2—Tl182.8 (3)
O3iii—Tl2—O1ii114.3 (2)O3vii—O2—Tl166.7 (3)
O3ix—Tl2—O1ii73.3 (2)O3—O2—Tl166.7 (3)
O3x—Tl2—O1ii144.0 (2)O1—O2—Tl1118.0 (4)
O1i—Tl2—O1ii67.2 (2)Tl2xiii—O2—Tl1170.3 (4)
O2xi—Tl2—O1ii107.5 (2)Tl1ii—O2—Tl187.4 (2)
O2i—Tl2—O1iii79.9 (2)Tl1iii—O2—Tl187.4 (2)
O3iv—Tl2—O1iii114.3 (2)Tl2xvii—O2—Tl184.0 (2)
O3iii—Tl2—O1iii45.9 (2)S—O3—O235.9 (3)
O3ix—Tl2—O1iii144.0 (2)S—O3—O3vii34.8 (3)
O3x—Tl2—O1iii73.3 (2)O2—O3—O3vii59.5 (2)
O1i—Tl2—O1iii67.2 (2)S—O3—O135.2 (2)
O2xi—Tl2—O1iii107.5 (2)O2—O3—O160.5 (4)
O1ii—Tl2—O1iii132.5 (4)O3vii—O3—O160.1 (2)
O2i—Tl2—Tl1ix126.58 (7)S—O3—Tl2iii109.2 (3)
O3iv—Tl2—Tl1ix54.5 (2)O2—O3—Tl2iii119.2 (3)
O3iii—Tl2—Tl1ix109.67 (13)O3vii—O3—Tl2iii127.25 (13)
O3ix—Tl2—Tl1ix54.58 (13)O1—O3—Tl2iii74.3 (2)
O3x—Tl2—Tl1ix109.1 (2)S—O3—Tl2xviii160.9 (4)
O1i—Tl2—Tl1ix126.55 (7)O2—O3—Tl2xviii142.8 (4)
O2xi—Tl2—Tl1ix49.281 (11)O3vii—O3—Tl2xviii126.77 (14)
O1ii—Tl2—Tl1ix60.5 (2)O1—O3—Tl2xviii156.6 (4)
O1iii—Tl2—Tl1ix153.5 (2)Tl2iii—O3—Tl2xviii87.0 (2)
O2i—Tl2—Tl1xii126.58 (7)S—O3—Tl1iii98.7 (4)
O3iv—Tl2—Tl1xii109.67 (13)O2—O3—Tl1iii66.6 (2)
O3iii—Tl2—Tl1xii54.5 (2)O3vii—O3—Tl1iii125.56 (13)
O3ix—Tl2—Tl1xii109.1 (2)O1—O3—Tl1iii99.4 (4)
O3x—Tl2—Tl1xii54.58 (13)Tl2iii—O3—Tl1iii84.7 (2)
O1i—Tl2—Tl1xii126.55 (7)Tl2xviii—O3—Tl1iii92.6 (2)
O2xi—Tl2—Tl1xii49.281 (10)S—O3—Tl1xvi89.4 (4)
O1ii—Tl2—Tl1xii153.5 (2)O2—O3—Tl1xvi124.5 (3)
O1iii—Tl2—Tl1xii60.5 (2)O3vii—O3—Tl1xvi68.25 (11)
Tl1ix—Tl2—Tl1xii98.51 (2)O1—O3—Tl1xvi78.7 (3)
O2i—Tl2—Tl193.3 (2)Tl2iii—O3—Tl1xvi78.7 (2)
O3iv—Tl2—Tl148.9 (2)Tl2xviii—O3—Tl1xvi83.9 (2)
O3iii—Tl2—Tl148.9 (2)Tl1iii—O3—Tl1xvi163.2 (2)
O3ix—Tl2—Tl1142.69 (15)S—O3—Tl186.7 (3)
O3x—Tl2—Tl1142.69 (15)O2—O3—Tl171.5 (3)
O1i—Tl2—Tl145.1 (2)O3vii—O3—Tl168.32 (11)
O2xi—Tl2—Tl1109.0 (2)O1—O3—Tl1121.8 (3)
O1ii—Tl2—Tl169.4 (2)Tl2iii—O3—Tl1163.6 (2)
O1iii—Tl2—Tl169.4 (2)Tl2xviii—O3—Tl178.07 (15)
Tl1ix—Tl2—Tl1103.381 (11)Tl1iii—O3—Tl189.1 (2)
Tl1xii—Tl2—Tl1103.381 (11)Tl1xvi—O3—Tl1106.1 (2)
O2—S—O3vii108.1 (4)
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1, z+1; (iii) x+1, y, z+1; (iv) x+1, y+1/2, z+1; (v) x+1/2, y+1/2, z+1/2; (vi) x+1/2, y, z+1/2; (vii) x, y+1/2, z; (viii) x+3/2, y+1/2, z1/2; (ix) x+3/2, y+1/2, z+1/2; (x) x+3/2, y, z+1/2; (xi) x+1/2, y+1/2, z+3/2; (xii) x+3/2, y1/2, z+1/2; (xiii) x1, y, z; (xiv) x, y+1, z+1; (xv) x, y, z+1; (xvi) x1/2, y+1/2, z+1/2; (xvii) x1/2, y+1/2, z+3/2; (xviii) x+3/2, y1/2, z1/2.

Experimental details

Crystal data
Chemical formulaTl2SO4
Mr504.80
Crystal system, space groupOrthorhombic, Pnma
Temperature (K)293
a, b, c (Å)7.818 (1), 5.931 (1), 10.634 (2)
V3)493.08 (14)
Z4
Radiation typeMo Kα
µ (mm1)65.60
Crystal size (mm)0.11 × 0.04 × 0.02
Data collection
DiffractometerSyntex Nicolet P3F
diffractometer
Absorption correctionAnalytical
(de Meulenaer & Tompa, 1965)
Tmin, Tmax0.074, 0.356
No. of measured, independent and
observed [I > 2σ(I)] reflections
605, 605, 571
Rint0.000
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.025, 0.064, 1.04
No. of reflections605
No. of parameters41
Δρmax, Δρmin (e Å3)1.60, 1.58

Computer programs: reference?, SHELXS86 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), SHELXL97.

Selected bond lengths (Å) top
Tl1—O1i2.843 (11)Tl2—O3iv2.910 (7)
Tl1—O2ii3.013 (2)Tl2—O3iii2.910 (7)
Tl1—O2iii3.013 (2)Tl2—O3viii2.942 (6)
Tl1—O3iv3.029 (9)Tl2—O3ix2.942 (6)
Tl1—O3iii3.029 (9)Tl2—O1i3.071 (12)
Tl1—O3v3.250 (9)Tl2—O2x3.082 (10)
Tl1—O3vi3.250 (9)Tl2—O1ii3.239 (5)
Tl1—O3vii3.260 (7)Tl2—O1iii3.239 (5)
Tl1—O33.260 (7)S—O21.461 (10)
Tl1—O23.366 (8)S—O3vii1.467 (6)
Tl1—O1v3.651 (12)S—O31.467 (6)
Tl2—O2i2.801 (8)S—O11.480 (11)
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1, z+1; (iii) x+1, y, z+1; (iv) x+1, y+1/2, z+1; (v) x+1/2, y+1/2, z+1/2; (vi) x+1/2, y, z+1/2; (vii) x, y+1/2, z; (viii) x+3/2, y+1/2, z+1/2; (ix) x+3/2, y, z+1/2; (x) x+1/2, y+1/2, z+3/2.
Bond valence sums, Tl-E distances (Å) and E positions top
AtomBond valenceTl-E distanceE coordinates
sum(a)(b)(a)(b)xyz
Tl1[11]0.8400.8400.0770.1520.6551/40.404
Tl2[9]1.0440.9890.1600.0770.9851/40.701
S[4]5.1866.094
Notes: (a) Pannetier & Gaultier (1966b); (b) this work.
 

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