Cs10Tl6SiO4, Cs10Tl 6GeO4, and Cs10Tl6SnO3 - First oxotetrelate thallides, double salts containing "hypoelectronic" [Tl6]6- clusters

Article abstract of DOI:10.1002/zaac.201000358

Cs₁₀Tl₆TtO₄ (Tt = Si, Ge) and Cs ₁₀Tl₆SnO₃ were synthesized by the reaction of appropriate starting materials at 623-673 K, followed by fast cooling or quenching to room temperature, in arc

Full text of DOI:10.1002/zaac.201000358

ARTICLE
DOI: 10.1002/zaac.201000358
Cs Tl SiO , Cs Tl GeO , and Cs Tl SnO – First Oxotetrelate Thallides,
1
0
6
4
10
6
4
10
6
3
6–
Double Salts Containing “Hypoelectronic” [Tl ] Clusters
6
[a]
[a]
[a]
Vyacheslav Saltykov, Jürgen Nuss, and Martin Jansen*
Dedicated to Professor Wolfgang Kaim on the Occasion of His 60th Birthday
Keywords: Cesium; Thallium; Cluster compounds; Crystal structures; Physical properties
Abstract. Cs10Tl
6
TtO
4
(Tt = Si, Ge) and Cs10Tl
6
SnO
3
were synthe- showing almost not any direct interaction between the two anionic
Tl ][Cs SiO ].
sized by the reaction of appropriate starting materials at 623–673 K, moieties, as might be expressed e.g. by the formula [Cs
6
6
4
4
followed by fast cooling or quenching to room temperature, in arc- In contrast to the silicon and germanium compounds, where the oxida-
welded tantalum ampoules. According to single-crystal X-ray analyses, tion state of the tetrel atom is unambiguously 4+, for the threefold
the compounds crystallize in new structure types (Cs10Tl
6
TtO
4
(Tt = coordinated tin atom in Cs10Tl
6 3
SnO an oxidation state of 2+ has to
6–
Si, Ge), P2
which can be characterized as distorted octahedra compressed along “hypoelectronic” [Tl
one of the fourfold axes of an originally unperturbed octahedron, and and is intrinsically stable. The distortion of [Tl
1 6 3 6
/c and Cs10Tl SnO , Pnma), consisting of [Tl ]
clusters, be assumed. Thus, the latter reveal further evidence that the so called
6–
6
]
cluster does not require additional electrons
6–
6
]
can be understood
anions. The oxotetrelate thallides can in terms of the Jahn–Teller theorem. According to magnetic measure-
be regarded as “double salts”, which consist of Cs Tl on one side ments all title compounds are diamagnetic.
4
–
4–
4–
[SiO
4
] , [GeO
4
]
3
or [SnO ]
6
6
and respective oxosilicates, -germanates and -stannates on the other,
Introduction
producing closed shell configurations, and showing a large
HOMO–LUMO gap, are particularly stable. Recently, we have
For the class of homoatomic clusters or network anions con-
sisting of post-transition elements, concepts are available that
allow to rationalize in an elegant and empirical manner the
respective compositions, geometries and electron counts.
6–
demonstrated that for two different [Tl8] clusters, which do
not comply with pertinent qualitative concepts, closed shell
configurations result due to Jahn–Teller distortion or, for the
[17,18]
first time, to spin-orbit coupling.
The latter effect, stabi-
[1–4]
These are the famous and popular Zintl–Klemm concept
lizing both cluster geometries, is of relativistic origin exclu-
sively, which would explain the exceptional role of thallium in
cluster chemistry.
and Wade’s rules.[ Inherently, all empirical classification
5]
schemes show limited ranges of validity as well as certain
exceptions.[
6–9]
This also holds true for both of the approaches,
Our approaches to generate new thallium ions, in particular
the elusive monoatomic anion, include to increase the compo-
sitional and structural degrees of freedom by introducing addi-
tional anionic species. The reaction of alkali metals with thal-
lium in the presence of the respective alkali metal oxides has
yielded a series of interesting new oxide thallides, e.g.
mentioned. In particular for thallium, which has shown to offer
a rich and diverse chemistry of anionic clusters, neither the
Zintl–Klemm concept nor Wade’s rules straightforwardly ap-
ply, in most of the cases encountered. Frequently, the clusters
appear to be deficient in skeletal electrons, even falling below
the limits as defined by Wade. They have been denoted “hypo-
electronic” clusters, and the discrepancies to the qualitative
bonding concepts have been tentatively attributed to a lower
degree of localization of the skeletal bonds and to structural
distortions that create additional bonds along body or face
diagonals.[
[9]
[19]
[17]
Cs Tl O, A Tl O (A = K, Rb)
or Cs Tl O .
In ex-
8
8
10
6
2
18
8
6
tending this idea, we have explored the systems cesium, ce-
sium oxide and thallium with silicon dioxide, germanium diox-
ide and elemental tin. The targeted mixed anion phases formed
indeed, and we present here the first cesium silicate thallide,
germanate thallide, and stannate thallide.
6,10–16]
The underlying common principle of the Zintl–Klemm con-
cept and of Wade’s rules is that structures with electron counts
Experimental Section
*
Prof. Dr. M. Jansen
Synthesis
Fax: +49-711-689-1502
E-Mail: M.Jansen@fkf.mpg.de
Because reagents and products are very sensitive to air and moisture,
all operations were performed under dried argon (Schlenk technique or
glovebox with H
[
a] Max-Plank-Institut für Festkörperforschung
Heisenbergstr. 1
70569 Stuttgart, Germany
2
O, O
2
< 0.1 ppm; MB 150B–G–II, M. Braun GmbH,
Z. Anorg. Allg. Chem. 2011, 637, 1163–1168
© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1163

V. Saltykov, J. Nuss, M. Jansen
ARTICLE
München, Germany). Cs10Tl
6
SiO
4
, Cs10Tl
6
GeO
4
and Cs10Tl
6
SnO
3
ture of less than 2 at-% of CsTl phase. The corresponding reactions
were prepared by the reaction of cesium (synthesized from CsCl by with SnO (Sigma–Aldrich, 99.99 %) or SnO
2
(Chempur, Jülich, pow-
reduction with calcium and distilled twice in vacuum ) with thallium der, 99.999 %) lead to formation of at least two phase samples (con-
ChemPur, Jülich, granules, 99.999 %), SiO (Sigma–Aldrich, Riedel- sisting e.g. of CsTl and Cs10Tl SnO ) with CsTl (< 65 %) as the main
de-Haën, 99 %), GeO (ChemPur, Jülich, 99.999 %), tin (Alfa Aesar, product. In contrast to the previous two compounds, Cs10Tl GeO was
shot, 99.8 %) and Cs
[20]
(
2
6
3
2
6
4
2
O (synthesized from cesium by oxidation with produced by quenching the quartz ampoule in ice-water cooling bath
a slight deficiency of oxygen followed by distillation of the cesium after applying a temperature profile of heating with a rate of 50 K·h–1
excess[ ). Thallium, tin, silicium dioxide and germanium dioxide up to 623 K and annealing at this temperature for 3 days. In each
21]
–
3
were dried before use at 393 K in dynamic vacuum at 10 mbar dur- case unreacted elemental cesium was distilled off at 373 K in dynamic
ing 12 h. The starting materials for the syntheses of Cs10Tl SiO
and vacuum of 10–3 mbar. The products were isolated and handled under
Cs10Tl GeO (total amount of 1–2 g) were weighed out in the molar strictly inert conditions (Schlenk technique or glovebox).
ratios Cs:Cs O:Tl:SiO (GeO ) = 12–14:2.2:6:1 and of Cs10Tl SnO
Cs:Cs
6
4
6
4
2
2
2
6
3
–
2
O:Tl:Sn = 15–20:4.5:6:1, afterwards placed into tantalum tubes,
which were sealed under argon with an arc welder. In order to prevent Analyses
oxidation, the tantalum tubes were encapsulated in silica jackets, under
The atom ratios of heavy elements was confirmed by using a scanning
electron microscope (XL 30 TMP, Philips, Holland, tungsten electrode,
argon. Cs10Tl
6 4
SiO was synthesized by heating the reaction mixture
–
1
with a rate of 50 K·h up to 673 K, annealing at this temperature for
2
5 kV), equipped with an integrated EDAX–EDX system (S–UTW–
2
2
days, and afterwards cooling to room temperature with a rate of
Si(Li)–detector). The difference of the ratio of the elements between
calculated and measured values did not exceed 1 at-%.
–
1
00 K·h . In order to obtain an as pure phase as possible (admixture
Tl11), and to avoid decomposition of the
Tl11, CsTl and SiO phases, cooling down to
room temperature with high speed was indispensable. For the synthesis
of Cs10Tl SnO , the reaction mixture of cesium, Cs O, thallium and
of less than 2 at-% of Cs
sample resulting in Cs
8
8
2
Structure Determination
6
3
2
–
1
tin was heated with a rate of 50 K·h up to 773 K, annealed at this Appropriate single crystals were mounted in a glass capillary, inside
temperature for 2 days, and afterwards cooled to room temperature the glovebox. Intensity data were collected on an APEX–SMART–
–
1
with a rate of 200 K·h , which resulted in pure phase with an admix- diffractometer (Bruker-AXS, Karlsruhe, Germany) at 293 K with
Table 1. Crystal and structure refinement data for Cs10Tl
Cs10Tl SiO
P2 /c (14); 4
6
SiO
4
, Cs10Tl
Cs10Tl
P2 /c (14); 4
6
GeO
4 6 3
and Cs10Tl SnO .
6
4
6
GeO
4
6 3
Cs10Tl SnO
Space group (no.); Z
Cell parameters /Å
1
1
Pnma (62); 4
a = 14.8908(8)
b = 19.052(1)
c = 11.5855(6)
a = 18.9121(16)
b = 11.4386(10)
c = 14.8081(13)
β = 90.029(2)
3203.4(5)
a = 19.034(2)
b = 11.488(1)
c = 14.863(2)
β = 90.033(2)
3250.0(6)
2691.91
5.501
Block, metallic black
0.18 × 0.12 × 0.08
3
Volume /Å
3286.8(3)
–
1
Molar weight /g·mol
2647.41
2722.01
–
3
Density (calculated) /g·cm
Crystal form, color
Crystal size /mm
Diffractometer
5.489
Block, metallic black
0.25 × 0.18 × 0.12
5.501
Block, metallic black
0.22 × 0.14 × 0.12
Bruker AXS, APEX SMART CCD
Graphite
Monochromator
X-ray radiation, λ /Å
θ range /°
α
Mo-K , 0.71073
1.08 to 28.00
1.07 to 26.44
–23 ≤ h ≤ 23
–14 ≤ k ≤ 14
–18 ≤ l ≤ 18
2.06 to 29.23
–20 ≤ h ≤ 20
–26 ≤ k ≤ 25
–15 ≤ l ≤ 15
Index range
–24 ≤ h ≤ 24
–
15 ≤ k ≤ 15
19 ≤ l ≤ 19
–
Absorption correction
Total no. reflections Nall
Independent reflections N
SADABS[22]
34599
7721
6432
41.311
–
31064
6694
5378
41.588
0.000023(8)
4400
35963
4584
3620
40.965
–
Reflections with I > 2σ (I) N'
Absorption coefficient μ /mm
Extinction coefficient
F(000)
–
1
4328
4440
2
Refinement method
Weighting Scheme
Full-matrix least-squares on F
2
2
2
2
2
2
2
2
2
w = 1/[σ (F
o
) + (0.0094P) + w = 1/[σ (F
o
) + (0.0014P) +
w = 1/[σ (F
o
) + (0.0834P) +
8
0.3945P]
where P = (F
192
146.3297P]
74.2922P]
where P = (F
101
2
2) / 3
2
+ 2F 2
2
+ 2F 2
o
+ 2F
c
where P = (F
192
o
c
) / 3
o
c
) / 3
Number of free parameters
2
Goodness-on-fit on F
1.059
1.033
1.042
R
1
(N'; Nall
)
0.0500; 0.0610
0.1132; 0.1195
0.505(1), 0.495(1)
–3.31 / 2.78
0.0538; 0.0724
0.1217; 0.1321
0.0575; 0.0742
0.1637; 0.1814
–
–3.84 / 5.10
CSD-422189
2
wR (N'; Nall)
Twin volume fractions
0.594(1), 0.406(1)
–3.47 / 4.11
–
3
Δρmin; Δρmax /e·Å
Deposition no.
CSD-422187
CSD-422188
1164
www.zaac.wiley-vch.de
© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2011, 1163–1168

6 4 6 4 6 3
Cs10Tl SiO , Cs10Tl GeO and Cs10Tl SnO – First Oxotetrelate Thallides
graphite-monochromated Mo-K
α
radiation. Semiempirical absorption Table 3. Atomic coordinates and equivalent isotopic displacement pa-
2
correction (SADABS[ ) was applied. The structures were solved by
direct methods and refined by full-matrix least-squares fitting using
SHELXTL program package.[ Experimental details, atomic coordi-
nates and anisotropic displacement parameters are presented in Ta-
ble 1, Table 2, and Table 3. Further details of the crystal structure in-
vestigations may be obtained from Fachinformationszentrum
Karlsruhe, 76344 Eggenstein-Leopoldshafen, Germany (Fax: +49-
22]
rameter U /Å of Cs Tl SnO .
eq
10
6
3
Atom Site x
y
z
U
eq
23]
Tl1
Tl2
Tl3
8d 0.14219(4) 0.43669(4) 0.00455(5)
0.0485(2)
8d 0.04390(6) 0.56153(5) –0.17372(8) 0.0768(3)
8d 0.04762(5) 0.57249(5) 0.08929(9)
0.0740(3)
0.0546(4)
0.0575(4)
0.0652(5)
0.110(1)
Cs1 4c 0.2986(1)
Cs2 4c –0.0526(1)
Cs3 4c –0.0819(1)
¼
¾
¾
¼
–0.4615(1)
–0.1360(1)
0.2226(1)
–0.8313(2)
7
247-808-666; E-Mail: crysdata(at)fiz-karlsruhe.de, http://www.fiz-
karlsruhe.de/request_for_deposited_data.html) on quoting the appro- Cs4 4c 0.3120(2)
priate CSD number given in Table 1.
Cs5 8d 0.20153(7) 0.43310(6) –0.3173(1)
Cs6 8d 0.18762(7) 0.40475(6) 0.34306(9)
Cs7 8d 0.05982(9) 0.60051(8) –0.5623(2)
Sn
O1
O2
0.0554(3)
0.0516(3)
0.0792(4)
0.0300(3)
0.039(3)
Table 2. Atomic coordinates and equivalent isotopic displacement pa-
2
4c 0.07250(8)
4c 0.1753(9)
8d 0.1153(7)
¼
–0.5444(1)
–0.662(1)
–0.444()
rameter Ueq /Å of Cs10Tl
6
SiO
4
6 4
and Cs10Tl GeO (*).
¼
Atom Site x
Tl1A 4e 0.43464(6) 0.01452(8)
.43917(7)* 0.02076(9)* 0.14262(8)* 0.0474(3)*
Tl1B 4e 0.93017(6) –0.00773(8) –0.13845(7) 0.0505(2)
y
z
U
eq
0.3299(6)
0.042(2)
0.14101(8)
0.0562(2)
0
–1
623 K with a rate of 10 K·min , and then cooled down to room tem-
0
.92967(6)* –0.00546(9)* –0.13760(8)* 0.0451(3)*
perature with the same rate. Because all synthesized compounds are
sensitive to moisture and air, the thermal stability measurements were
performed in an argon atmosphere.
Tl2A 4e 0.56141(9) –0.1645(2)
0.0562(1)
0.1142(7)
0
.5462(1)* –0.1846(1)* 0.0427(1)*
0.0922(6)*
Tl2B 4e 0.07397(6) 0.1453(1)
–0.06604(8) 0.0644(3)
–0.06587(9)* 0.0577(3)*
0
.07546(6)* 0.1413(1)*
Tl3A 4e 0.57115(8) 0.1007(2)
.58030(8)* 0.0753(1)*
Tl3B 4e 0.06072(6) –0.1198(1)
0.04381(9)
0.0453(1)*
0.0982(5)
0.0817(5)*
0
Magnetic Measurements
–0.04347(8) 0.0630(3)
0
.05822(7)* –0.1223(1)* –0.04344(8)* 0.0541(3)*
Magnetization was measured using a SQUID magnetometer (MPMS
5.5, Fa., Quantum Design, USA) in the temperature range 5–300 K at
H = 0.001, 0.1, 1, 3, 5 and 7 T. The specimens (silicate, germanate or
stannate) were sealed in quartz tubes under helium. The raw data were
corrected for the holder contribution.
Cs1 4e 0.2450(1)
–0.4576(1)
0.31558(7)
0.0584(3)
0.0489(4)*
0
.2387(1)* –0.4543(2)* 0.3155(1)*
Cs2 4e 0.74652(9) –0.17230(9) –0.04314(8) 0.0509(3)
0
.7415(1)* –0.1739(1)* –0.0359(1)* 0.0439(4)*
Cs3 4e 0.7530(1) 0.2124(1) –0.0837(1) 0.0727(4)
.7553(1)* 0.2087(2)* –0.0855(2)* 0.0722(6)*
Cs4 4e 0.2546(2) –0.8291(1)
.2573(2)* –0.8416(2)* 0.3025(1)*
Cs5A 4e 0.4253(1) –0.3086(2) 0.2038(2)
.4177(1)* –0.2966(2)* 0.2138(2)*
Cs5B 4e 0.93450(9) 0.3210(1) –0.1967(1)
.9380(1)* 0.3217(2)*
Cs6A 4e 0.40822(8) 0.3523(2)
.4084(1)* 0.3598(2)*
Cs6B 4e 0.90658(8) –0.3423(1)
0
0.30934(9)
0.0824(5)
0.0869(8)*
0.0837(6)
0.0710(7)*
0.0564(4)
Results and Discussion
0
The title compounds were synthesized by reacting appropri-
ate starting materials at 623–673 K, followed by fast cooling
or quenching to room temperature, in arc-welded tantalum am-
poules. The products were obtained as black brittle crystals.
According to powder diffraction X-ray analysis, Cs Tl TtO
0
0
–0.19464(1)* 0.0553(5)*
0.1795(1)
0.1895(2)*
–0.1719(1)
0.0620(4)
0.0553(5)*
0.0562(4)
0
1
0
6
4
(
Tt = Si, Ge) and Cs Tl SnO were obtained as single phases
0
.9057(1)* –0.3386(2)* –0.1714(1)* 0.0506(5)*
10 6 3
Cs7A 4e 0.6179(1)
.6155(1)* –0.5517(2)* 0.0585(2)*
Cs7B 4e 0.1223(1) 0.5362(2) –0.0668(2)
.1244(1)* 0.5424(3)*
Si1 4e 0.2492(4) –0.5254(3)
–0.5424(2)
0.0599(2)
0.0745(5)
0.0667(6)*
0.0817(6)
with less than 2 at-% admixtures of Cs Tl or CsTl. The
8 11
0
chemical compositions were confirmed by EDX analysis, and
no impurity elements were detected. The title compounds are
extremely sensitive to moisture and air. According to DSC as
well as high-temperature powder X-ray analysis measure-
ments, Cs Tl SiO is stable up to 573 K, Cs Tl GeO up to
0
–0.0719(2)* 0.0840(8)*
0.0983(2)
0.0331(8)
0.0250(4)*
0.039(2)
0.036(3)*
0.050(4)
0.038(4)*
0.037(3)
0.035(4)*
0.047(3)
Ge1 4e 0.2504(1)* –0.5259(2)* 0.0974(1)*
O1 4e 0.2512(9)
.251(1)*
O2A 4e 0.3187(8)
–0.6386(9)
–0.646(1)*
–0.444(1)
0.1701(6)
0.174(1)*
0.122(1)
10
6
4
10
6
4
0
4
83 K and Cs Tl SnO at least up to 623 K.
10 6 3
The diffraction intensities of the crystals of Cs Tl SiO and
10
6
4
0
.3212(8)* –0.436(1)*
0.122(1)*
–0.117(1)
–0.118(1)*
–0.0066(6)
Cs Tl GeO were first indexed and integrated assuming or-
O2B 4e 0.8232(7)
.8261(9)* 0.444(1)*
O3 4e 0.248(1) –0.573(1)
.2522(9)* –0.572(1)*
0.448(1)
10
6
4
0
thorhombic symmetry, with quite reasonable internal R values
Cs Tl SiO : R = 0.064, Cs Tl GeO : R = 0.125). Both
(
1
0
6
4
int
10
6
4
int
0
–0.0144(9)* 0.034(3)*
structures can be refined within the space group Pnma
(
(
no. 62), but with unsatisfactory reliability values
Cs Tl SiO : R = 0.114, Cs Tl GeO : R = 0.239) and unu-
10
6
4
1
10
6
4
1
sual displacement parameters (mainly for the thallium atoms).
Careful inspection of the reciprocal space using the Precession
Differential Scanning Calorimetry
[24]
module of the Bruker Suite software package, which allows
a detailed exploration of the reciprocal space without being
Differential Scanning Calorimetry (DSC) was performed with a com-
puter controlled DSC sensor (DSC 404 C Pegasus, Netzsch GmbH,
[25]
Selb, Germany). Powder samples (~15 mg) were placed in Al cruci- restricted to integer hkl values, revealed some of the forbid-
bles, which were cold sealed under argon in a glovebox, heated to den reflections 0kl: k + l ≠ 2n (n gliding plane) to be present,
Z. Anorg. Allg. Chem. 2011, 1163–1168
© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1165

V. Saltykov, J. Nuss, M. Jansen
ARTICLE
[34]
[35]
and furthermore minute splitting of reflections at higher 2θ Na [GeO ],
d(Ge–O) = 1.75–1.78 Å in Rb [GeO ],
4
4
4
4
[33]
values. The final structure refinements in the monoclinic space d(Ge–O) = 1.73–1.79 Å in Rb [Sn ] [GeO ] ,
and d(Ge–
The angles ∠O–
1
2
4 2
4 3
[33]
group P2 /c (no. 14), assuming dovetail-twinning (twinning by O) = 1.72–1.77 Å in Cs [Sn ] [GeO ] .
1
12
4 2
4 3
pseudo-merohedry, β ≈ 90°) has led to significantly improved Ge–O are in the range of 107.5–112.4°, this deviation from the
R-values and more reasonable displacement parameters (Ta- ideal tetrahedral arrangement is similar to other known ortho-
4
–
ble 1 and Table 2).
germanates. The anionic unit [SnO ] , present in Cs Tl SnO ,
3 10 6 3
The structurally related Cs Tl SnO crystallizes in the or- displays ψ – tetrahedral coordination of tin by three oxygen
10
6
3
thorhombic space group (Pnma, no. 62), and no necessity was ligands, forming an anion with approximate C3v point group
found to use lower symmetry, or to even apply twin refinement symmetry. This anion has a shape corresponding to those
[
26,27]
[36]
[37]
[38]
(Table 1 and Table 3). The group–subgroup relation
be- found in Cs SnO ,
K SnO ,
Na SnO3
as well as in
4
3
4
3
4
[
39]
tween the aristotype Cs Tl SnO and Cs Tl Si(Ge)O (Fig- recently synthesized Cs [Sn ] [SnO ] [O] [O ].
In accord-
10
6
3
10
6
4
48
4 4
3 4
7
2
ure 1) includes one step of symmetry reduction of type trans- ance with the VSEPR model the bonding angles ∠O–Sn–O are
lationengleich (t2);[ we regard the corresponding transition much smaller than the ideal tetrahedral angle, and range from
occurring at cooling down from the reaction temperature the 97.6 to 98.5°, which is comparable to other stannates(II).[
reason for twinning of the silicon and germanium representa-
28]
36–39]
tives. According to the group-subgroup relation, each 4c site
in the orthorhombic space group corresponds to one 4e site in
the monoclinic one, and each atom, located on an 8d site in
orthorhombic Cs Tl SnO splits into two 4e sites in mono-
1
0
6
3
clinic Cs Tl SiO , see Figure 1. For better comparison, corre-
1
0
6
4
sponding atoms are labeled with the same number but with
additional letters A and B, if necessary, see Table 2 and Ta-
ble 3.
Figure 1. Group-subgroup relation between the Cs10Tl
6 3
SnO and
Cs10Tl SiO , crystal structures, including the site transformations.
6
4
The title compounds crystallize in new structure types (Fig-
ure 2), which consist of octahedral [Tl ] clusters, [SiO ],
6
4
[
GeO ] and [SnO ] oxoanions, respectively, and isolated ce-
4 3
sium cations. Selected bond lengths as well as the angles
within the complex oxoanions are summarized in Table 4. The
shape of the orthosilicate(IV) anion deviates only marginally
from tetrahedral arrangement (106.5° ≤ ∠O–Si–O ≤ 113.6°),
with Si–O bond lengths d(Si–O) of 1.65 to 1.68 Å (Table 4),
corresponding to those in other known orthosilicates: d(Si–
[
29]
O) = 1.63–1.64 Å in K SiO ,
d(Si–O) = 1.60–1.65 Å in
4
4
[
30]
[31]
Li SiO , d(Si–O) = 1.64–1.65 Å in K LiSiO , d(Si–O) = Figure 2. Perspective representations of the crystal structures of
4
4
3
4
[
32]
1
.61–1.68 Å in Cs Li SiO
6 4 6 3
as well as recently synthesized Cs10Tl TtO (Tt = Si and Ge) (a) and Cs10Tl SnO (b) (green lines
2
2
4
[33]
mark the unit cell edges, blue spheres – thallium atoms, green
spheres – cesium atoms, grey spheres – silicon, germanium or tin at-
oms, red spheres – oxygen atoms); vertical black lines at the bottom
Cs [Sn ] [SiO ] (d(Si–O) = 1.60–1.70 Å). The Ge–O dis-
2
0
4 2
4 3
tances in Cs Tl GeO range from 1.74 to 1.78 Å (Table 4)
1
0
6
4
and are also similar to the distances in known orthogermanates
emphasize the intergrowth type of structure, consisting of Cs
6 6
Tl and
with tetrahedral GeO4 units: d(Ge–O) = 1.75–1.78 Å in Cs
4
TtO (Tt = Si and Ge) or Cs SnO slabs.
4
4
3
1166
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© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2011, 1163–1168

Cs10Tl
6
SiO
4
6
, Cs10Tl GeO
4
6 3
and Cs10Tl SnO – First Oxotetrelate Thallides
2
]6– octahedra /
/d
Table 4. Selected bond lengths /Å and angles /° of Cs10Tl
6
TtO
4
(Tt = Table 5. Lengths of the space diagonals (Tl–Tl) of [Tl
6
Si, Ge) and Cs10Tl
6
SnO
3
.
Å in various compounds.
Cs10Tl SiO
6
4
Cs10Tl
6
GeO
4
Cs10Tl
6
SnO
3
Compound
Tl–Tlcompressed (d
1
)
Tl–Tlexpanded (d
2
)
d
2
1
[11]
Tl1A –Tl3A 3.039(2) 3.026(2)
Tl1 –Tl3 3.033(1)
–Tl3 3.105(1)
–Tl2 3.394(1)
–Tl2 3.474(1)
CsTl
3.741(5)
3.805(3)
3.573(7)
3.578(5)
3.800(7)
4.836(3) × 2
4.814(2) × 2
4.941(1) × 2
4.933(2) × 2
4.765(8)
1.293
1.265
1.383
1.379
1.254
1.284
1.251
1.285
1.297
1.306
[
10]
–
–
–
Tl3A 3.116(2) 3.114(2)
Tl2A 3.388(2) 3.348(2)
Tl2A 3.394(2) 3.453(2)
KTl
Rb10Tl
10Tl
[
19]
6
O
2
[19]
K
6
O
2
Tl1B –Tl3B 3.068(2) 3.074(2)
Cs10Tl
Cs10Tl
Cs10Tl
6
6
6
SiO
GeO
SnO
4
–
–
–
Tl3B 3.117(2) 3.123(2)
Tl2B 3.407(2) 3.405(2)
Tl2B 3.414(1) 3.418(2)
4.879(5)
4
3.804(5)
3.731(1)
4.757(6)
4.889(0)
Tl2A –Tl3A 3.001(2) 3.015(3)
Tl2 –Tl3 3.055(2)
–Tl3 3.055(1)
–Tl1 3.394(1)
–Tl1 3.474(1)
3
4.838(3)
–
–
–
Tl3A 3.044(3) 3.056(3)
Tl1A 3.388(2) 3.347(2)
Tl1A 3.394(2) 3.453(2)
4.874(7)
Tl2B –Tl3B 3.035(2) 3.026(2)
–
–
–
Tl3B 3.061(2) 3.064(2)
Tl1B 3.407(2) 3.405(2)
Tl1B 3.414(1) 3.418(2)
transfer electrons to the thallium cluster. Thus one can consider
Tl6]6– clusters to not require additional electrons and to be
[
Tl3A –Tl2A 3.001(2) 3.015(3)
Tl3 –Tl1 3.033(1)
–Tl2 3.055(2)
–Tl2 3.055(1)
–Tl1 3.105(1)
intrinsically stable. The distortion can be understood in terms
of the Jahn–Teller theorem. The compression of the octahedron
along one of its diagonals reduces its point group symmetry to
D , thus splitting the t skeleton molecular orbital (MO) into
–
–
–
Tl1A 3.039(2) 3.026(2)
Tl2A 3.044(3) 3.056(3)
Tl1A 3.116(2) 3.114(2)
4
h
1u
Tl3B –Tl2B 3.035(2) 3.026(2)
eu and a MOs, the latter one becoming antibonding. As a
–
–
–
Tl2B 3.061(2) 3.064(2)
Tl1B 3.068(2) 3.074(2)
Tl1B 3.117(2) 3.122(2)
2u
result, the 24 valence electrons now occupy exclusively bond-
ing or non-bonding MOs, thus stabilizing the cluster
Tt
–O3
1.65(1) 1.74(2)
1.65(2) 1.74(1)
1.65(2) 1.76(2)
1.68(1) 1.78(1)
1.68(1) 1.78(1)
1.65(2) 1.74(2)
1.65(1) 1.76(2)
1.65(1) 1.74(1)
Sn –O2
–O1
2.02(1)×2
2.05(1)
[11]
(
Figure 3).
The same structural feature has been observed
–
–
–
O2A
6–
for all [Tl ] cluster containing compounds, known so
6
O2B
O1
[
10,11,19]
far.
O1
–Tt
O1 –Sn
O2 –Sn
2.05(1)
2.02(1)
O2A –Tt
O2B –Tt
O3
–Tt
O2A–Tt–O3
113.6
109.7
108.5
110.7
107.5
112.4
107.9
O2–Sn–O2 97.6(6)
O2–Sn–O1 98.5(4)×2
O2A–Tt–O2B 108.8
O2B–Tt–O3
O2A–Tt–O1
O3–Tt–O1
108.7
106.5
110.2
109.1
O2B–Tt–O1
All title compounds contain [Tl ]6– clusters, which can be
6
characterized as a distorted octahedron, with the Tl–Tl distan-
ces ranging from 3.03 to 3.47 Å (Table 4). The intercluster Tl–
Tl separations are clearly larger ( ≥ 6.8 Å). The thallium clus-
ter anions all display similar distortion patterns: one of the
space diagonals of the octahedra is significantly compressed.
The ratios of the length of compressed diagonals (d ) and the
1
8
–
averaged expanded ones (d ) serve as a quantitative measure Figure 3. MO diagrams (qualitative sketch) of the [Tl ] (O ) and
2
6
h
6–
for the distortions encountered in various representatives (Ta- [Tl
6
]
(D4h) clusters [11].
ble 5).
The Tl groups in the compounds under discussion provide
The three oxotetralide thallides presented here can be re-
6
further examples of so called “hypoelectronic” thallium clus- garded as “double salts”. On the basis of an ionic description,
ters (skeleton electron concentration = 24e, which is less than Cs Tl6 on one hand and the oxosilicates, -germanates and
6
6
× 4 + 2 = 26e (inert-electron pairs included), which is the -stannates on the other hand, constitute binary and ternary, re-
polyhedral electron number required according to Wade’s spective, partial structures, which form the quaternary structure
[40]
rule). An ideal (all diagonals of equal lengths) Tl cluster obey- by inhomogeneous intergrowth, cf. Figure 2.
6
ing Wade’s rule should bear a charge of 8–, as it has been
observed for Na K Tl M (M = Mg, Zn).
The magnetic susceptibility is negative and temperature in-
[
12]
It is remarkable dependent in the range investigated (50–300K) for all magnetic
1
4
6
18
6–
that in Cs Tl SnO the hypoelectronic [Tl ] cluster is found fields applied, which is indicative for diamagnetic compounds:
1
0
6
3
6
although tin, present in the oxidation state 2+, could easily χmol = –3.1 × 10–4 ± 2.5 % emu·mol for Cs Tl SiO , χ
–1
=
10
6
4
mol
Z. Anorg. Allg. Chem. 2011, 1163–1168
© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1167

V. Saltykov, J. Nuss, M. Jansen
ARTICLE
[
17] U. Wedig, V. Saltykov, J. Nuss, M. Jansen, J. Am. Chem. Soc.
2010, 132, 12458–12463.
1
–
5 × 10–4 ± 2.5 % emu·mol–1 for Cs Tl GeO and χmol
=
10 6 4
–
4
–1
6.5 × 10
± 2.5 % emu·mol for Cs Tl SnO at field
10 6 3
[18] V. Saltykov, J. Nuss, U. Wedig, M. Jansen, Z. Anorg. Allg. Chem.
strength 3 T and approximates the sum of diamagnetic core
2010, 636, 2040.
+
+
4+
2–
corrections (10χ(Cs ) + 6χ(Tl ) + χ(Si ) + 4χ(O ) = –5.628 × [19] A. Karpov, M. Jansen, Chem. Commun. 2006, 1706–1708.
–
4
–1
+
+
4+
1
0
emu·mol for Cs Tl SiO ; 10χ(Cs ) + 6χ(Tl )+ χ(Ge ) [20] G. Brauer, Handbuch der Präparativen Anorganischen Chemie,
10 6 4
2
–
–4
–1
Vol. 2, Ferdinand Enke, Stuttgart, Germany, 1978, pp. 938–942.
[21] G. Brauer, Handbuch der Präparativen Anorganischen Chemie,
Vol. 2, Ferdinand Enke, Stuttgart, Germany, 1978, pp. 953–954.
[22] G. M. Sheldrick, SADABS, Bruker AXS Area Detector Scaling
and Absorption, Version 2008/1, University of Göttingen, Ger-
many, 2008.
+
4χ(O ) = –5.692 × 10 emu·mol
for Cs Tl GeO ;
1
0
=
6
4
+
+
2+
2–
1
1
0χ(Cs )
+
6χ(Tl )
+
χ(Sn )
+
4χ(O )
–5.7 ×
–4
–1
0
emu·mol for Cs Tl SnO ) and the Larmor susceptibility
10
6
3
[
41,42]
–4
–1
of the cluster orbital electrons
(–0.8 × 10 emu·mol
–
–4
–1
Cs Tl SiO , –0.8 × 10 emu·mol – Cs Tl GeO , –0.79 ×
1
0
6
4
10
6
4
–4
–1
[23] G. M. Sheldrick, Acta Crystallogr., Sect. A 2008, 64, 112–122.
10
emu·mol – Cs Tl SnO ).
10 6 3
[
[
[
24] Bruker Suite, Version 2008/3, Bruker AXS Inc., Madison, WI,
USA, 2008.
25] J. Nuss, N. Z. Ali, M. Jansen, Acta Crystallogr., Sect. B 2007, 63,
Acknowledgement
The authors thank E. Brücher for performing the magnetic measure-
ments.
719–725.
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dratschek, U. Müller), Dordrecht, Kluwer Academic Publishers,
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27] U. Müller, Z. Anorg. Allg. Chem. 2004, 630, 1519–1537.
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Received: October 5, 2010
Published Online: December 1, 2010
1168
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© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2011, 1163–1168