Synthesis and crystal structure of Te6[MCl6] (M = Zr, Hf), containing a polymeric chalcogen cation (Te62+) n

Article abstract of DOI:10.1002/zaac.200400285

The reaction of tellurium, tellurium tetrachloride, and ZrCl₄ or HfCl₄, respectively, under the conditions of chemical vapour transport in a temperature gradient 220 → 200°C yields black crystals of Te₆[ZrCl₆] and Te₆[HfCl₆]. While Te₆[ZrCl₆] is formed almost quantitatively, Te ₆[HfCl₆] is always accompanied by neighbored phases such as Te₄[HfCl₆] and Te₈[HfCl₆]. The crystal structures of Te₆[ZrCl₆] (orthorhombic, Pbcm, a = 1095.4(1), b = 1085.2(1), c = 1324.5(1) pm) and Te₆[HfCl₆] (a = 1094.8(2), b = 1086.3(2), c = 1325.0(2) pm) are isotypic and consist of one-dimensional polymeric (Te₆²⁺)_n cations and of discrete, only slightly distorted octahedral [MCl₆]^2- anions (M = Zr, Hf). The cations are build of five membered rings which are connected via single Te atoms to a polymer -Te-Te₅-Te-Te ₅-. Out of the six Te atoms of the asymmetric unit of the chain four atoms exhibit two bonds and two atoms exhibit three bonds. The connecting, threefold coordinated Te atoms of the five membered rings carry formally the positive charges. In consistence with the assumption of the presence of throughout localized bonds eH band structure calculations for Te ₆[ZrCl₆] show semiconducting behaviour with a band gap of 1.8 eV.

Full text of DOI:10.1002/zaac.200400285

Synthesis and Crystal Structure of Te [MCl ] (M ؍ Zr, Hf), Containing a
6
6
2
؉
Polymeric Chalcogen Cation (Te )
6
n
Alexander Baumann und Johannes Beck*
Bonn, Institut für Anorganische Chemie der Universität
Received July 7th, 2004.
th
Dedicated to Professor Michael Veith on the Occasion of his 60 Birthday
Abstract. The reaction of tellurium, tellurium tetrachloride, and
ZrCl or HfCl , respectively, under the conditions of chemical vap-
our transport in a temperature gradient 220 Ǟ 200 °C yields black
crystals of Te [ZrCl ] and Te [HfCl ]. While Te [ZrCl ] is formed
almost quantitatively, Te [HfCl ] is always accompanied by neigh-
bored phases such as Te [HfCl ] and Te [HfCl ]. The crystal struc-
tures of Te [ZrCl ] (orthorhombic, Pbcm, a ϭ 1095.4(1), b ϭ
085.2(1), c ϭ 1324.5(1) pm) and Te [HfCl ] (a ϭ 1094.8(2), b ϭ
086.3(2), c ϭ 1325.0(2) pm) are isotypic and consist of one-dimen-
5 5
atoms to a polymer ϪTeϪTe ϪTeϪTe Ϫ. Out of the six Te atoms
4
4
of the asymmetric unit of the chain four atoms exhibit two bonds
and two atoms exhibit three bonds. The connecting, threefold coordi-
nated Te atoms of the five membered rings carry formally the posit-
ive charges. In consistence with the assumption of the presence of
throughout localized bonds eH band structure calculations for
6
6
6
6
6
6
6
6
4
6
8
6
6
6
Te
6 6
[ZrCl ] show semiconducting behaviour with a band gap of
1
1
6
6
1.8 eV.
2ϩ
sional polymeric (Te
torted octahedral [MCl
6
)
n
cations and of discrete, only slightly dis-
Keywords: catena-Hexatellurium(2ϩ); hexachlorozirconate(IV);
hexachlorohafnate(IV); chalcogen polycations; main group element
cluster; inorganic polymer; crystal structure
]2 anions (M ϭ Zr, Hf). The cations are
Ϫ
6
build of five membered rings which are connected via single Te
Synthese und Kristallstruktur von Te [MCl ] (M ؍ Zr, Hf) mit einem polymeren
6
6
2
؉
Kation (Te
)
6
n
Inhaltsübersicht. Die Reaktion von Tellur, Tellurtetrachlorid und
ZrCl bzw. HfCl unter den Bedingungen des chemischen Gaspha-
sentransports ergibt bei 220 Ǟ 200 °C schwarze Kristalle von
Te [ZrCl ] und Te [HfCl ]. Während Te [ZrCl ] nahezu einphasig
gebildet wird, entstehen im System Te/TeCl /HfCl die Phasen
Te [HfCl ], Te [HfCl ] und Te [HfCl ] nebeneinander. Die Kristall-
strukturen von Te [ZrCl ] (orthorhombisch, Pbcm, a ϭ 1095,4(1),
b ϭ 1085,2(1), c ϭ 1324,5(1) pm) und Te [HfCl ] (a ϭ 1094,8(2),
b ϭ 1086,3(2), c ϭ 1325,0(2) pm) sind isotyp und bestehen aus
gering verzerrt oktaedrischen [MCl
Kationen sind aus fünfgliedrigen Ringen aufgebaut, die über ein-
zelne Te-Atome zu einem Polymer ϪTeϪTe ϪTeϪTe Ϫ verknüpft
sind. Von den sechs Te-Atomen der asymmetrischen Einheit der
Kette sind vier zweibindig und zwei dreibindig. Die dreibindigen
]2Ϫ-Anionen (M ϭZr, Hf). Die
6
4
4
5
5
6
6
6
6
6
6
4
4
4
6
6
6
8
6
Te-Atome in den Te
5
-Ringen tragen formal die positiven Ladun-
6
6
gen. In Übereinstimmung mit der Annahme nur lokalisierter Bin-
6
6
6 6
dungen zeigen eH-Bandstrukturrechnungen für Te [ZrCl ] Halblei-
terverhalten mit einer Bandlücke von etwa 1,8 eV.
2ϩ
eindimensional-polymeren (Te
6
n
) -Kationen und diskreten, nur
ϩ
planar Se 2 and Te42ϩ cations were found in the structures
Introduction
4
of Se [ZrCl ], Se [HfCl ], and Te [HfCl ] [6, 7]. The octa-
4
6
4
6
4
6
The tetrahalides of group 14 metals Zr and Hf have strong
Lewis acidic properties. Predominantly discrete, octahedral
2ϩ
2ϩ
atomic chalcogen cations Se8 and Te8 are present in the
structures of the respective hexachlorozirconates and haf-
nates E [MCl ] (E ϭ Se, Te; M ϭ Zr, Hf) [8]. Te [Zr Br ]
2
Ϫ
[
MX6]
anions (M ϭ Zr, Hf; X ϭ halogen) are formed
8
6
4
2
10
which consequently exhibit only weakly basic properties.
These anions are able to stabilize “naked” polycationic clus-
ters. Several compounds made up of polycationic clusters
and group 14 halometalate anions are meanwhile known.
occurs as a polycation-containing phase in the system Te/
TeBr /ZrBr [9].
4
4
2ϩ
The fact that two different tellurium cations Te4 and
2ϩ
Te8 are formed in the system Te/TeCl /MCl (M ϭ Zr,
4
4
5
ϩ
Bi9
clusters are present in the hexagonal structures of
Hf) stimulated us to search for additional phases. We were
Bi(Bi )[MX ] (M ϭ Zr, Hf, Nb; Xϭ Cl, Br) [1Ϫ5]. Square-
9
6 3
able to isolate Te [MCl ] (M ϭ Zr, Hf) containing a novel
6
6
polymeric tellurium polycation Te62 on which we report
ϩ
here.
*
Prof. Dr. J. Beck
Inst. f. Anorg. Chemie d. Universität
Gerhard-Domagk-Str. 1
D-53121 Bonn
Experimental
Te (99,5 %, Johnson-Matthey) was molten in an evacuated glass
ampoule and decanted from oxidic impurities. The crystallized sil-
e-mail: j.beck@uni-bonn.de
2078
 2004 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
DOI: 10.1002/zaac.200400285
Z. Anorg. Allg. Chem. 2004, 630, 2078Ϫ2082

6 6
Synthesis and Crystal Structure of Te [MCl ] (M ϭ Zr, Hf)
6 6 6 6
Table 1 Crystallographic data and details of the structure refinement for Te [ZrCl ] and Te [HfCl ]. Standard deviations given in brackets
refer to the last significant digit.
Formula
Te
6
[ZrCl
6
]
6 6
Te [HfCl ]
Crystal system/space group
Lattice constants
orthorhombic Pbcm (No. 57)
a / pm
b / pm
c /pm
V /10 pm
Z
1095.4(1)
1085.2(1)
1324.5(1)
1574.4(2)
4
1094.8(2)
1086.3(2)
1325.0(2)
1575.8(3)
4
6
3
Unit cell volume
Number of formula units
Density (calculated)
Ϫ3
/ g · cm
4.51
4.88
Temperature
/ K
293(2)
6.1° < 2Θ < 56°
14340
1980, Rint ϭ 0.091
1980
67
293(2)
10.3° < 2Θ < 55.9°
14058
1955, Rint ϭ 0.117
1955
67
Range of data collection
Number of measured reflections
Number of independent reflections
Number of reflections in least squares
Number of refined parameters
Absorption correction
Numerical, description of the crystal shape by
Ϫ1
Ϫ1
1
5 faces, µ ϭ 125.8 mm
10 faces, µ ϭ 184.9 mm
Reliability factors
R(ΗFΗ) for [number] reflections with
> 4σ(F
F
o
o
)
0.028 [1903]
0.029
0.070
0.038 [1892]
0.039
0.090
all reflections
2
wR(F )
/ e/10 pm
6
3
Final difference fourier
ϩ1.08 / Ϫ1.02
ϩ2.25 / Ϫ3.39
very material was finely ground in an argon atmosphere. TeCl
prepared from purified Te and dry chlorine. It was freshly subli-
mated before use. ZrCl and HfCl (both Aldrich, 99,5 % and 98 %,
4
was
Table 2 Positional coordinates and equivalent isotropic displace-
4
2
ment parameter Beq/10 pm for the atoms in the structures of
Te [ZrCl ] and Te [HfCl ]. Standard deviations refer to the last si-
4
4
6
6
6
6
respectively) were sublimated in closed evacuated glass ampoules
before use.
6 6
gnificant digit. The respective values for Te [HfCl ] are given in
italics in the respective second line.
Te
(
(
6
[MCl
3.92 mmol), 151 mg TeCl
1.12 mmol) or 359 mg HfCl
6
] (M ؍ Zr, Hf). In an argon filled glove box 500 mg Te
(0.56 mmol), and 261 mg ZrCl
(1.12 mmol), respectively, were filled
Atom
x
y
z
B
eq
4
4
4
Te1
Te2
Te3
Te4
0.18058(3)
0.40191(3)
0.40209(4)
0.37089(3)
0.37088(4)
0.25
Ϫ0.10084(2)
Ϫ0.10088(4)
0.02268(2)
0.02304(4)
0
1.831(8)
1.47(1)
1.907(8)
1.55(1)
1.92(1)
1.56(1)
2.22(1)
1.84(1)
1.37(1)
1.35(1)
2.58(3)
2.80(5)
2.03(3)
2.10(5)
2.88(2)
2.54(3)
2.70(2)
2.34(3)
0
.18047(4)
in a glass ampoule of 15 cm length and 1.5 cm internal diameter.
The ampoules were evacuated and flame-sealed, and placed in a
horizontal tube furnace. The furnace was heated to 220 °C and the
ampoule placed asymmetrically, so a temperature gradient of 20 °C
from the hot, charged end to the empty tip of the ampoule was
established. Within 3 weeks black, shiny crystals of Te
formed in almost quantitative yield which were deposited in the
colder part of the reaction ampoule. Using HfCl always a mixture
of the phases Te [HfCl ], Te [HfCl ], and Te [HfCl ] was formed.
The visual distinction is difficult and can be made only for
Te [HfCl ] the crystals of which exhibit a typical dark violet luster.
0.38569(3)
0.38545(4)
0.01882(4)
0
.01866(6)
0.25
0
0.26536(4)
0.26554(7)
0.73864(5)
0.73876(3)
0.5695(3)
0.23851(5)
0.23846(6)
0.20112(6)
0.20100(3)
0.0556(2)
0.0569(3)
0.3384(2)
0.3378(2)
0.3291(1)
0.3283(2)
0.0731(1)
0.0735(1)
Ϫ0.25
Ϫ0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.1191(1)
0.1201(2)
0.3801(1)
0.3797(2)
Zr
Hf
Cl1
6 6
[ZrCl ]
0
.5698(3)
4
Cl2
Cl3
Cl4
0.9141(2)
0.9133(2)
0.6438(1)
4
6
6
6
8
6
0
.6442(2)
0.8435(1)
.8432(2)
4
6
0
Crystal Structure Analyses
Since all compounds are sensitive towards hydrolysis by moist air,
opening of the reaction ampoules and selection of crystals was per-
formed in an argon filled glove box. Crystals were filled into glass
capillaries, which were sealed. The crystals selected had the size
1, positional parameters in Table 2, selected bond lengths and
angles in Table 3. Further information on the crystal structure
analyses have been deposited with the FIZ Karlsruhe, D-76344
Eggenstein-Leopoldshafen form where they can be obtained by
quoting the deposit numbers CSD-414293 for Te [ZrCl ] and
0.34 · 0.30 · 0.53 mm for M ϭ Zr and 0.27 · 0.30 · 0.30 mm for
6
6
M ϭ Hf. Preliminary examinations by precession photographs re-
vealed the orthorhombic crystal system for both crystals. Data sets
were recorded at ambient temperature using a STOE IPDS dif-
fractometer with graphite monochromatized Mo-Kα radiation.
The systematic absences: 0kl only present for k ϭ 2n, and h0l only
6 6
CSD-414294 for Te [HfCl ].
Results and Discussion
Synthesis
1
present for l ϭ 2n lead to the possible space groups Pbc2 and
Pbcm of which the centrosymmetric group turned out as correct
The formation of Te [M ϭ Zr, Hf) can formally be inter-
6
through the refinement calculations. Structure models were ob-
2
preted as a comproportionation of tellurium and tellurium-
tetrachloride to a subvalent intermediate followed by a
Lewis acid base reaction. ZrCl
tained by direct methods [10] and refined against F with aniso-
tropic displacement parameters for all atoms [11]. A numerical ab-
sorption correction was applied to both data sets [12]. Crystallo-
graphic data and details of the structure analyses are given in Table
and HfCl act as Lewis ac-
4
4
ids, abstracting chloride ions from the intermediate subhal-
Z. Anorg. Allg. Chem. 2004, 630, 2078Ϫ2082
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2079

A. Baumann, J. Beck
Table 3 Selected bond lengths / pm and angles / ° in the structures
of Te [ZrCl ] and Te [HfCl ]. The values for Te [HfCl ] are given
6
6
6
6
6
6
in italics in the respective second line. Standard deviations refer to
the last significant digit. Symmetry operations are given in the le-
gend for Figure 1.
Te1ϪTe2
Te1ϪTe3
Te1ϪTe4
Te2ϪTe2I
279.97(4)
89.12(7)
276.43(4)
76.67(6)
281.24(5)
81.62(7)
269.18(7)
69.63(9)
ZrϪCl1
HfϪCl1
ZrϪCl2
HfϪCl2
ZrϪCl3
HfϪCl3
ZrϪCl4
HfϪCl4
243.4(2)
242.4(2)
243.1(2)
242.1(2)
245.3(1)
243.8(2)
249.3(1)
248.5(2)
2
2
2
2
Te2ϪTe1ϪTe3
Te3ϪTe1ϪTe4
Te2ϪTe1ϪTe
99.23(1)
9.06(2)
100.08(2)
00.01(2)
493.99(1)
4.01(2)
Te1ϪTe2ϪTe2I
Te1ϪTe3ϪTe1I
Te1ϪTe4ϪTe1III
89.24(1)
89.15(2)
100.27(2)
100.37(3)
89.25(2)
89.11(3)
9
1
9
ogenide under formation of the polycationic cluster and the
respective hexachlorometalate.
4 4 6 6
11 Te ϩ TeCl ϩ 2 MCl Ǟ 2 Te [MCl ] (M ϭ Zr, Hf)
The reaction proceeds via the gas phase in closed evacuated
ampoules. Since MCl (M ϭ Zr, Hf) are both volatile and
4
TeCl is known to be a stable gas phase species [13], chemi-
2
cal transport is achieved in a closed system with a tempera-
ture gradient from 220 Ǟ 200 °C.
2
ϩ
n 6
) cation and the [HfCl
]2Ϫ
Fig. 1 A section of the polymeric (Te
anion in the structure of Te [HfCl ]. Thermal ellipsoides are drawn
to include a probability density of 50 %.
6
6
6
A remarkable difference was observed in the reactivity of
ZrCl and HfCl . The reaction of Te, TeCl , and HfCl
1
1
4
4
4
4
2 2
Symmetry operations: I ϭ x, / Ϫ y, Ϫz; II ϭ x, y, / Ϫ z; III ϭ
1
yielded in all experiments simultaneously all three Hf/Te/Cl
phases Te [HfCl ], Te [HfCl ], Te [HfCl ], together with other
2
x, y, Ϫ / Ϫ z.
4
6
6
6
8
6
yet unidentified phases. While the crystals of Te [HfCl ]
4
6
show a typical dark violet luster, the visual distinction be-
tween the black crystals of Te [HfCl ] and Te [HfCl ] was
{
314,6(2) pm} and Te(3)····Cl(4) ϭ 314.5(1) pm {314.8(1)
6
6
8
6
pm}. These distances are shorter than the respective short-
est Te····Cl contacts in the structures of Te [HfCl ] (324.9
pm [6]) and Te [HfCl ] (322.9 pm [8]).
The cations consist of five-membered rings in a twist con-
formation which are connected by single Te atoms leading
to one-dimensional strands according to the formula
not possible. Using Te, TeCl , and ZrCl , however, the com-
4
4
4
6
pound Te [ZrCl ] is formed in almost quantitative yield.
6
6
8 6
The neighboured phases Te [ZrCl ] and Te [ZrCl ] could
4
6
8
6
not be detected.
2ϩ
(ϪTeϪTe Ϫ )n. Crystallographic twofold axes run perpen-
5
Crystal Structures
dicular to the direction of the chain through the atoms
Te(3) and the centre of the Te(2)ϪTe(2) bond. The atoms
Te(4) are located in mirror planes spread out perpendicular
to the running direction of the cationic chains. The conse-
quence is that translational equivalence within the (Te62 )n
I
Te [ZrCl ] and Te [HfCl ] crystallize isotypically. The struc-
6
6
6
6
2
ϩ
tures contain one-dimensional polycations (Te )n and dis-
crete octahedral anions [MCl6] . No significant diffences
in bond lenghts and angles are present between Te [ZrCl ]
6
2
Ϫ
ϩ
6
6
and Te [HfCl ]. Figure 1 gives a view of a section of the cat-
strand is reached only with every second Te ring. Figure 2
6
6
5
ionic chain and of the anion.
Crystallographic mirror planes bisect the anions. The
atoms M (M ϭ Zr, Hf), Cl(1) and Cl(2) are located in the
shows the unit cell and a stereoscopic view of the coordi-
nation environment of the five-membered ring of the cat-
ions. Eight anions coordinate the Te ring in form of a dis-
5
mirror planes giving the anions C symmetry. The deviation
torted cube. The structure of Te [MCl ] (M ϭ Zr, Hf) thus
S
6
6
from the ideal octahedral symmetry is significant. The
MϪCl bond lengths range from 242 to 249 pm, the
ClϪMϪCl angles from 87° to 93°. These deviations are
caused by strong cation-anion interactions. The shortest
TeϪCl distances between the Cl atoms of the anions and
the Te atoms of the cations are Te(2)····Cl(3) ϭ 313.5(1) pm
adopts the CsCl structure type. This is reflected by the lat-
tice constants, which remind of a tetragonally elongated cu-
bic cell. The elongation of the cell occurs along the c direc-
tion which is the direction of the cationic strands.
The Zintl concept can be applied to explain the relation
between charge and structure of the cation. In each
2080
 2004 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
zaac.wiley-vch.de
Z. Anorg. Allg. Chem. 2004, 630, 2078Ϫ2082

6 6
Synthesis and Crystal Structure of Te [MCl ] (M ϭ Zr, Hf)
Fig. 2 The unit cell of Te
6 6
[MCl ] (M ϭ Zr, Hf) in a view inclined
to the b-axis (top) and a stereoscopic view of the cuboidal coordi-
2
Ϫ
nation of the cationic ϪTeϪTe
5
ϪTeϪ group by eight [MCl
6
]
an-
ions (bottom).
Fig. 3 The structures of the known one-dimensional polymeric
chalcogen cations composed of linked rings. The numbers on the
left refer to a simple structure designator code (see text).
2
ϩ
(
ϪTe ϪTeϪ) section of the chain there are two threefold
5
I
coordinated Te atoms (Te(1) and Te(1) ), while all other Te
atoms are twofold coordinated. A chalcogen atom bearing
five valence electrons behaves like an atom of group 15 and
thus exhibits three bonds and carries formally a positive
charge. The bridgehead atoms Te(1) have a trigonal pyrami-
dal coordination environment typical for three bonds of p
character and a stereochemically active lone pair. The
TeϪTe bonds show a pronounced bond lengths alternation.
TeϪTe bond lengths involving the threefold coordinate
are depicted in Figure 3. The ring size varies between four
and six, the number of atoms in the connecting chains var-
2ϩ
ies between zero in (Te )n (Fig. 3a) [19] and three in
4
(Te Se )n and (Te3.15Se4.852ϩ) (Figs. 3b and 3d) [20].
2
ϩ
3
4
ϩ
n
(Te62 )n with its structure of five-membered rings connec-
ted via ϪTeϪ bridges fits in this series. A simple structure
designator code can be set up since the different chains can
unequivocally be termed by the parameters ring size and
number of connecting atoms. The first digit gives the num-
ber of atoms in the respective rings, the second digit gives
the number of bridging atoms. So for (Te62 )n the structure
designator is 5-1. In Figure 3 the respective structure desig-
nation codes are given for all known chainlike chalcogen
Te(1) and the ring linking Te(4) are ranging from 277 to
82 pm. The Te(2)ϪTe(2) distance is only 269 pm indicat-
I
2
ing partial double bond character. The TeϪTeϪTe angles
are all in the typical range between 90° and 100° (Tab. 3)
and are thus slightly smaller than in the element structure
of tellurium (103,1°) [14].
Several cationic tellurium chains are known since about
one decade [15, 16]. They can be divided in two kinds. The
first kind exhibits hypervalent bonding with square planar
coordinated Te atoms, present for example as (Te72 )n in
the structures of Te [WOBr ]Br [17], Te [NbOCl ]Cl [18] or
ϩ
polycations, ranging from 4-0 in (Te42 )n to 6-2 in (Te8 ) ,
ϩ
2ϩ
n
realized as two isomers in the structures of Te [U Br ]
8
2
10
ϩ
(Fig. 3 f) [22] and Te [Bi Cl ] (Fig. 3 g) [23]. The only other
8
4
4
reprensentative known so far having a single atom bridge
7
4
7
4
2
ϩ
2ϩ
(
Te10 )n in (Te )(Te )[Bi Cl ] [19]. The second kind con-
between the rings was (Te7 )n in the structure of
4
10
4
16
tains only twofold and threefold coordinated Te atoms. The
bonding situation can thus be interpreted by simple models.
As a common structural feature, caused by the necessity of
the presence of threefold coordinated atoms, the structures
are all made up of rings which are connected either directly
or by short chains of Te atoms. The known representatives
Te [AsF ] (Fig. 3e) [21]. The structures of Te [MCl ] (Mϭ
7
6 2
6
6
Zr, Hf) and Te [AsF ] have another unique common fea-
7
6 2
ture. They are the only representatives which contain be-
sides a polymeric chalcogen cation discrete monomeric
anions. All other compounds composed of polymeric chal-
cogen cations also contain polymeric anions.
Z. Anorg. Allg. Chem. 2004, 630, 2078Ϫ2082
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 2004 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
2081

A. Baumann, J. Beck
on the Te atoms. In line with the formal description the
effective charges on the Te atoms Te(2), Te(3), and Te(4)
are very low, not exceeding ϩ0.15 units, while the threefold
coordinated Te(1) exhibits a charge of ϩ0.83.
References
[
[
1] R. M. Friedman, J. Corbett, Inorg. Chem. 1973, 12, 1134.
2] A. N. Kuznetsov, A. V. Shevel’kov, S. I. Troyanov, B. A. Popov-
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[
[
3] A. N. Kuznetsov, A. V. Shevel’kov, B. A. Popovkin, Russ. J.
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4] A. N. Kuznetsov, P. I. Naumenko, B. A. Popovkin, L. Kloo,
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[
[
5] J. Beck, T. Hilbert, Eur. J. Inorg. Chem. 2004, 2019.
6] J. Beck, K.-J. Schlitt, Chem. Ber. 1995, 128, 763.
7] J. Beck, A. Desgrosseiliers, K. Müller-Buschbaum, K.-J.
Schlitt, Z. Anorg. Allg. Chem. 2002, 628, 1145.
8] A. Baumann, J. Beck, T. Hilbert, Z. Naturforsch. 1999, 54b,
1253.
[
6 4
Fig. 4 The total density of states (DOS) for Te [ZrCl ] as obtained
by an eH band structure calculation. The dotted line represents the
integration over all states, the broken line indicates the niveau of
the Fermi energy E .
F
[9] J. Beck, Chem. Ber. 1991, 124, 677.
[10] G. M. Sheldrick, SHELXS-97, Program for Crystal Structure
Solution, University of Göttingen, Germany, 1997.
[11] G. M. Sheldrick, SHELXL-93, Program for Crystal Structure
Refinement, University of Göttingen, Germany, 1993.
The structure of the cation (Te62ϩ) in Te [MCl ] (M ϭ
[12] The crystal shape used for the absorption correction was opti-
mized with the aid of the program HABITUS: W. Herrendorf,
H. Bärnighausen, Universities of Karlsruhe and Gießen, Ger-
many, 1993 and 1997.
[13] L. Fernholt, A. Haaland, H. V. Volden, R. Kniep, J. Mol.
Struct. 1985, 128, 29.
[14] C. Adenis, V. Langer, O. Lindqvist, Acta Crystallogr. 1989,
C45, 941.
[15] J. Beck, Coord. Chem. Rev. 1997, 163, 55.
[16] S. Brownridge, I. Krossing, J. Passmore, H. D. B. Jenkins, H.
K. Roobottom, Coord. Chem. Rev. 2000, 197, 397.
n
6
6
Zr, Hf) shows distinct differences to the cations in the struc-
tures of Te [WOCl ] [24] and Te [NbOCl ] [25]. Both the
6
4 2
6
4 2
latter compounds consist of discrete molecular Te62 cat-
ions in the form of six-membered rings which are in a
strongly bent boat conformation and remind of a trigonal
prism with two open edges. However, no simple mechanism
ϩ
2
ϩ
for a polymerisation of the discrete Te
meric strand of (Te6 )n can be set up without substantial
rearrangement of the atoms.
ions to the poly-
6
2
ϩ
[17] J. Beck, Angew. Chem. 1991, 103, 1149; Angew. Chem. Int. Ed.
Since one-dimensional infinite bonding is present in the
structure of Te [MCl ] (MϭZr, Hf) we performed band
Engl. 1991, 30, 1128.
6
6
[
[
18] J. Beck, G. Bock, Z. Anorg. Allg, Chem. 1994, 620, 1971.
19] J. Beck, A. Fischer, A. Stankowski, Z. Anorg. Allg. Chem.
structure calculations on the extended Hückel level [26] to
gain insight into the chemical bonding especially along the
polymeric Te chain. In the band structure no electronic
bands are crossing the level of the Fermi energy which was
calculated to Ϫ7.6 eV. The next and unoccupied bands are
2002, 628, 2542.
[20] J. Beck, Th. Schlörb, Phosphorus, Sulfur, Silicon, Rel. Elem.
1997, 124, 125.
[21] G. W. Drake, G. L. Schimek, J. W. Kolis, Inorg. Chem. 1996,
35, 1740.
1
.8 eV higher in energy, indicating that Te [ZrCl ] is a semi-
6 6
[
[
[
[
[
22] J. Beck, A. Fischer, Z. Anorg. Allg. Chem. 2002, 628, 369.
23] J. Beck, A. Stankowski, Z. Naturforsch. 2001, 56b, 453.
24] J. Beck, Chem. Ber. 1994, 128, 23.
25] J. Beck, G. Bock, Z. Anorg. Allg. Chem. 1994, 620, 1971.
26] G. Landrum, YAeHMOP, Yet another Extended Hückel Mo-
lecular Orbital Package, Cornell University, USA, 1995. The
following STO parameters were used for the atom orbitals
conductor. Figure 4 shows the total density of states. The
total density of states reaches zero at the Fermi level. The
projected DOS shows that the highest occupied band be-
tween Ϫ7.6 and Ϫ12 eV is mainly originated by Te p or-
bitals indicating the electron dispersion along the Te chain.
Since this band is completely filled with electrons the polyc-
ationic structure can be termed electron precise. The shape
of the first unoccupied band is very acute and corresponds
to Zr 5s orbitals. A population analysis gives the charges
1 2
(Hij[eV]/ζ /ζ ): Te 5s Ϫ19.122/2.470, 5p Ϫ9.540/2.036; Zr 5s
Ϫ5.735/1.360, 5p Ϫ3,694/1.151, 4d Ϫ8.461/2.769/1.224; Cl 3s
Ϫ29.196/2.250, 3p Ϫ13.780/1.900.
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Z. Anorg. Allg. Chem. 2004, 630, 2078Ϫ2082