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Single crystals of SnTe 3 O 8 in the millimetre range grown by chemical vapor transport reactions

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Tin(IV) trioxidotellurate(IV), SnTe 3 O 8 , is a member of the isotypic M IV Te IV 3 O 8 ( M = Ti, Zr, Hf, Sn) series crystallizing with eight formula units per unit cell in space group Ia \overline{3}. In comparison with the previous crystal structure model of SnTe 3 O 8 based on powder X-ray diffraction data [Meunier & Galy (1971). Acta Cryst. B 27 , 602–608], the current model based on single-crystal X-ray data is improved in terms of precision and accuracy. Nearly regular [SnO 6 ] octahedra (Sn site symmetry .\overline{3}.) are situated in the voids of an oxidotellurate(IV) framework built up by corner-sharing [TeO 4 ] bisphenoids (Te site symmetry 2..). A quantitative structural comparison revealed a very high degree of similarity for the structures with M = Ti, Zr, Sn in the M IV Te 3 O 8 series.
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research communications
Acta Cryst. (2021). E77 https://doi.org/10.1107/S2056989021011828 1of4
Received 5 November 2021
Accepted 8 November 2021
Edited by W. T. A. Harrison, University of
Aberdeen, Scotland
Keywords: crystal structure; oxidotellurates;
isotypism; electron lone pair.
CCDC reference:2120742
Supporting information:this article has
supporting information at journals.iucr.org/e
Single crystals of SnTe
3
O
8
in the millimetre range
grown by chemical vapor transport reactions
Michael Ketter and Matthias Weil*
Institute for Chemical Technologies and Analytics, Division of Structural Chemistry, TU Wien, Getreidemarkt 9/164-SC,
A-1060 Vienna, Austria. *Correspondence e-mail: matthias.weil@tuwien.ac.at
Tin(IV) trioxidotellurate(IV), SnTe
3
O
8
, is a member of the isotypic M
IV
Te
IV3
O
8
(M= Ti, Zr, Hf, Sn) series crystallizing with eight formula units per unit cell in
space group Ia3. In comparison with the previous crystal structure model of
SnTe
3
O
8
based on powder X-ray diffraction data [Meunier & Galy (1971). Acta
Cryst. B27, 602–608], the current model based on single-crystal X-ray data is
improved in terms of precision and accuracy. Nearly regular [SnO
6
] octahedra
(Sn site symmetry .3.) are situated in the voids of an oxidotellurate(IV)
framework built up by corner-sharing [TeO
4
] bisphenoids (Te site symmetry 2..).
A quantitative structural comparison revealed a very high degree of similarity
for the structures with M= Ti, Zr, Sn in the M
IV
Te
3
O
8
series.
1. Chemical context
The crystal chemistry of oxidotellurates(IV) is dominated by
the presence of the 5s
2
electron lone pair that, in the majority
of cases, is stereochemically active, thus enabling one-sided
coordination spheres around the Te
IV
atom (Christy et al.,
2016). This peculiar building block often results in compounds
with non-centrosymmetric structures or structures with polar
directions exhibiting interesting physical properties (Ra et al.,
2003; Kim et al., 2014). In this context, the microwave
dielectric properties of M
IV
Te
3
O
8
(M= Sn, Zr) ceramics were
investigated some time ago (Subodh & Sebastian, 2008).
The crystal structure of the isotypic series M
IV
Te
3
O
8
was
originally determined for M= Ti from a single crystal in space
group Ia3 using photographic Weissenberg X-ray data,
whereas for M= Sn, Zr and Hf, the crystal structures were
refined from powder X-ray data (Meunier & Galy, 1971). In
subsequent studies, crystal-structure refinements on the basis
of single-crystal X-ray data were reported for the mineral
winstanleyite with composition (Ti
0.96
Fe
0.04
)Te
3
O
8
(Bindi &
Cipriani, 2003), and for the synthetic compound ZrTe
3
O
8
(Noguera et al., 2003; Lu et al., 2019). A powder X-ray study of
the solid solution Sn
0.59
Ti
0.41
Te
3
O
8
crystallizing in the
M
IV
Te
3
O
8
structure type has also been reported (Ben Aribia
et al., 2008).
Single-crystal growth of oxidotellurates(IV) can be
accomplished through various crystallization methods
including, for example, experiments under hydrothermal
conditions (Weil et al., 2018), cooling from the melt (Sto
¨ger et
al., 2009), from salt melts as fluxing agents (Weil, 2019), or
from chemical vapor transport reactions (Missen et al., 2020).
The latter method (Binnewies et al., 2012) is particularly
suitable for growing large crystals of high quality and was the
ISSN 2056-9890
method of choice for crystal growth of SnTe
3
O
8
for which a
more precise and accurate structure refinement appeared to
be desirable.
2. Structural commentary
The asymmetric unit of SnTe
3
O
8
comprises one Sn
IV
atom, one
Te
IV
atom, and two oxide anions, residing on sites 8a(site
symmetry .3.), 24d(2..), 48e(1) and 16c(.3.), respectively. The
tin atom is in an almost regular octahedral coordination by
oxygen, with six equal Sn1—O1 distances, all trans angles
equal to 180,andcis angles ranging from 86.09 (4) to
93.91 (4). The Te1 site is coordinated by four O atoms in pairs
of shorter (O1) and longer distances (O2) (Table 1). The
resulting [TeO
4
] coordination polyhedron is a distorted bis-
phenoid. Considering the 5s
2
electron lone pair at the Te
IV
atom, the corresponding [Te O
4
] polyhedron has a shape
intermediate between a square pyramid and a trigonal
bipyramid with the non-bonding electron pair occupying an
equatorial position (Fig. 1). The geometry index
5
of the
[TeO
4
] polyhedron is 0.471 (
5
= 0 for an ideal square
pyramid and
5
= 1 for an ideal trigonal bipyramid; Addison et
al., 1984). The position of the electron lone pair was calculated
with the LPLoc software (Hamani et al., 2020), with resulting
fractional coordinates of x= 0.28655, y=0,z= 1/4. The radius
of the electron lone pair was calculated to be 1.07 A
˚with a
distance of 0.90 A
˚from the Te1 position. The coordination
numbers of the oxide anions are two and three: O1 coord-
inates to Sn1 and Te1 at the shorter of the two Te1—O
distances whereas O2 coordinates to three Te1 atoms at the
longer of the two Te1—O distances.
In the crystal structure of SnTe
3
O
8
, the [SnO
6
] octahedra
are isolated from each other and arranged in rows running
parallel to [100]. Each of the [TeO
4
] bisphenoids shares
corners (O2) with other [TeO
4
] bisphenoids to form a three-
dimensional oxidotellurate(IV) framework. The [SnO
6
] octa-
hedra are situated in the voids of this framework, thereby
sharing each of the six corners with an individual [TeO
4
] bis-
phenoid. The crystal structure of SnTe
3
O
8
is depicted in Fig. 2.
The unit-cell parameter afrom the previous powder X-ray
study, 11.144 (3) A
˚, as well as interatomic distances of Sn1—
O1 = 2.032 A
˚(6), Te1—O1 = 1.850 A
˚(2), Te1—O2 =
2.124 A
˚(2), and angles O1—Te1—O10= 102.9,andO2
2of4 Ketter and Weil SnTe
3
O
8
Acta Cryst. (2021). E77
research communications
Table 1
Selected geometric parameters (A
˚,).
Sn1—O1
i
2.0421 (11) Te1—O2 2.1278 (3)
Te1—O1
ii
1.8800 (11)
O1
iii
—Te1—O1
ii
102.42 (8) O2
iv
—Te1—O2 157.05 (6)
O1
iii
—Te1—O2 86.60 (6) Te1—O2—Te1
v
117.94 (2)
O1
ii
—Te1—O2 79.05 (4)
Symmetry codes: (i) xþ1
2;y;z1
2; (ii) zþ1
2;xþ1
2;yþ1
2; (iii) zþ1
2;x1
2;y;
(iv) x;y;zþ1
2; (v) z;x;y.
Figure 2
The crystal structure of SnTe
3
O
8
in polyhedral representation, showing a
projection along [100]. Displacement ellipsoids are as in Fig. 1; [TeO
4
]
polyhedra are red, [SnO
6
] octahedra are blue.
Table 2
Atom pairs and their absolute distances |u|(A
˚) in the isotypic series
MTe
3
O
8
with SnTe
3
O
8
as the reference structure, as well as degree of
lattice distortion (S), arithmetic mean of the distances (d
av
,A
˚) and
measure of similarity ().
TiTe
3
O
8a
(Ti
0.96
Fe
0.04
)Te
3
O
8b
ZrTe
3
O
8c
ZrTe
3
O
8d
M
IV
10 0 0 0
Te1 0.0475 0.0360 0.0065 0.0059
O1 0.1061 0.0834 0.0713 0.0694
O2 0.1374 0.0968 0.0543 0.0446
S0.0107 0.0102 0.0076 0.0092
d
av
0.0878 0.0668 0.0453 0.0436
0.011 0.008 0.006 0.006
Notes: (a)a= 10.956 (3) A
˚; Meunier & Galy (1971); (b)a= 10.965 (1) A
˚; Bindi &
Cipriani (2003); (c)a= 11.308 (1) A
˚; Noguera et al. (2003); (d)a= 11.340 (4) A
˚;Luet al.
(2019).
Figure 1
The coordination environment around Te1. Displacement ellipsoids are
drawn at the 90% probability level; the electron lone pair is given as a
green sphere of arbitrary radius. [Symmetry codes: (v) –z+1
2,x–1/2, y;
(vii) z+1
2,x+1
2,y+1
2; (viii) x,y,z+1
2.]
Te1 O2 0= 156.8(Meunier & Galy, 1971) agree with the
present single-crystal study (Table 1), but with lower precision
and accuracy. In comparison with the previous model based on
powder X-ray data, the values of the bond-valence sums
(Brown, 2002) using the parameters of Brese & O’Keeffe
(1991) are much closer to the expected values of 4 for Sn and
Te and 2 for O on basis of the current model [previous model:
Sn1 4.28 valence units (v.u.), Te1 4.10 v.u., O1 2.09 v.u., O2 2.08
v.u.; current model: Sn1: 4.14 v.u., Te1 3.93 v.u., O1 1.99 v.u., O2
2.00 v.u.].
The relation of the isotypic crystal structures of M
IV
Te
3
O
8
compounds with that of the fluorite structure has been
discussed previously for TiTe
3
O
8
(Meunier & Galy, 1971;
Wells, 1975). The unit-cell parameter aof cubic TiTe
3
O
8
is 2a
of cubic CaF
2
, whereby the ordered distribution of the cationic
sites leads to a doubling of the unit cell and also to a consid-
erable distortion of the respective coordination environments.
The original cubic coordination around the Ca
II
cation in the
fluorite structure is changed to an octahedral coordination of
Sn
IV
and a fourfold coordination of Te
IV
in the superstructure
of the M
IV
Te
3
O
8
compounds. Note that there are two addi-
tional O atoms at a distance of 3.2446 (19) A
˚around the M
IV
site and two pairs of additional O atoms at a distance of
2.9076 (12) and 3.3957 (13) A
˚around the Te1 site in SnTe
3
O
8
,
completing an eightfold coordination in each case. Corre-
spondingly, each of the two O sites has a fourfold coordination
in case the much longer distances are counted.
A quantitative structural comparison of the M
IV
Te
3
O
8
structures where single crystal data are available (M= Ti, Zr,
Sn) was undertaken with the program compstru (de la Flor et
al., 2016) available at the Bilbao Crystallographic Server
(Aroyo et al., 2006). Table 2 lists the degree of lattice distor-
tion (S), the maximum distance between the atomic positions
of paired atoms (|u|), the arithmetic mean of all distances, and
the measure of similarity () relative to SnTe
3
O
8
as the
reference structure. All these values show a very high simi-
larity between the crystal structures in the isotypic M
IV
Te
3
O
8
series.
3. Synthesis and crystallization
Reagent-grade chemicals were used without further purifica-
tion. SnO
2
(71 mg, 0.47 mmol) and TeO
2
(225 mg, 1.40 mmol)
were thoroughly mixed in the molar ratio 1:3 and placed in a
silica tube to which 50 mg of TeCl
4
were added as the transport
agent. The silica ampoule was then evacuated and torch-
sealed, placed in a two-zone furnace using a temperature
gradient 973 K (source) !873 K (sink) for three days. Cubic,
canary-yellow crystals had formed in the millimetre size range
in the colder sink region as the only product (Fig. 3). Powder
X-ray diffraction of the remaining material in the source
region revealed SnTe
3
O
8
as the main phase and SnO
2
as a side
phase. For the single-crystal diffraction study, a fragment was
broken from a larger crystal.
4. Refinement
Crystal data, data collection and structure refinement details
are summarized in Table 3. Atomic coordinates and the
labelling scheme were adapted from isotypic TiTe
3
O
8
(Meunier & Galy, 1971).
Acknowledgements
The X-ray centre of the Vienna University of Technology is
acknowledged for financial support and for providing access to
the single-crystal and powder X-ray diffractometers.
research communications
Acta Cryst. (2021). E77 Ketter and Weil SnTe
3
O
8
3of4
Figure 3
Photograph of Sn
3
TeO
8
single crystals grown by chemical vapor transport
reactions.
Table 3
Experimental details.
Crystal data
Chemical formula SnTe
3
O
8
M
r
629.49
Crystal system, space group Cubic, Ia3
Temperature (K) 296
a(A
˚) 11.1574 (4)
V(A
˚
3
) 1388.96 (15)
Z8
Radiation type Mo K
(mm
1
) 16.04
Crystal size (mm) 0.06 0.06 0.01
Data collection
Diffractometer Bruker APEXII CCD
Absorption correction Multi-scan (SADABS; Krause et
al., 2015)
T
min
,T
max
0.452, 0.748
No. of measured, independent and
observed [I>2(I)] reflections
14087, 735, 697
R
int
0.048
(sin /)
max
(A
˚
1
) 0.907
Refinement
R[F
2
>2(F
2
)], wR(F
2
), S0.014, 0.030, 1.07
No. of reflections 735
No. of parameters 21
max
,
min
(e A
˚
3
) 1.27, 0.86
Computer programs: APEX3 and SAINT (Bruker, 2018), SHELXL (Sheldrick, 2015),
ATOMS (Dowty, 2006) and publCIF (Westrip, 2010).
References
Addison, A. W., Rao, T. N., Reedijk, J., van Rijn, J. & Verschoor, G. C.
(1984). J. Chem. Soc. Dalton Trans. pp. 1349–1356.
Aroyo, M. I., Perez-Mato, J. M., Capillas, C., Kroumova, E.,
Ivantchev, S., Madariaga, G., Kirov, A. & Wondratschek, H.
(2006). Z. Kristallogr. 221, 15–27.
Ben Aribia, W., Loukil, M., Kabadou, A. & Ben Salah, A. (2008).
Powder Diffr. 23, 228–231.
Bindi, L. & Cipriani, C. (2003). Can. Mineral. 41, 1469–1473.
Binnewies, M., Glaum, R., Schmidt, M. & Schmidt, P. (2012).
Chemical Vapor Transport Reactions. Berlin, Boston: De Gruyter,.
Brese, N. E. & O’Keeffe, M. (1991). Acta Cryst. B47, 192–197.
Brown, I. D. (2002). The Chemical Bond in Inorganic Chemistry: The
Bond Valence Model. Oxford University Press.
Bruker (2018). APEX3 and SAINT. Bruker-AXS Inc. Madison,
Wisconsin, USA.
Christy, A. G., Mills, S. J. & Kampf, A. R. (2016). Miner. Mag. 80, 415–
545.
Dowty, E. (2006). ATOMS. Shape Software, Kingsport, Tennessee,
USA.
Flor, G. de la, Orobengoa, D., Tasci, E., Perez-Mato, J. M. & Aroyo,
M. I. (2016). J. Appl. Cryst. 49, 653–664.
Hamani, D., Masson, O. & Thomas, P. (2020). J. Appl. Cryst. 53 , 1243–
1251.
Kim, Y. H., Lee, D. W. & Ok, K. M. (2014). Inorg. Chem. 53, 5240–
5245.
Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J.
Appl. Cryst. 48, 3–10.
Lu, W., Gao, Z., Du, X., Tian, X., Wu, Q., Li, C., Sun, Y., Liu, Y. & Tao,
X. (2019). Inorg. Chem. 58, 7794–7802.
Meunier, G. & Galy, J. (1971). Acta Cryst. B27, 602–608.
Missen, O. P., Weil, M., Mills, S. J. & Libowitzky, E. (2020). Acta Cryst.
B76, 1–6.
Noguera, O., Thomas, P., Masson, O. & Champarnaud-Mesjard, J. C.
(2003). Z. Kristallogr. New Cryst. Struct. 218, 293–294.
Ra, H.-S., Ok, K. M. & Halasyamani, P. S. (2003). J. Am. Chem. Soc.
125, 7764–7765.
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8.
Sto
¨ger, B., Weil, M., Zobetz, E. & Giester, G. (2009). Acta Cryst. B65,
167–181.
Subodh, G. & Sebastian, M. T. (2008). Jpn. J. Appl. Phys. 47, 7943–
7946.
Weil, M. (2019). Acta Cryst. E75, 26–29.
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4of4 Ketter and Weil SnTe
3
O
8
Acta Cryst. (2021). E77
research communications
supporting information
sup-1
Acta Cryst. (2021). E77
supporting information
Acta Cryst. (2021). E77 [https://doi.org/10.1107/S2056989021011828]
Single crystals of SnTe3O8 in the millimetre range grown by chemical vapor
transport reactions
Michael Ketter and Matthias Weil
Computing details
Data collection: APEX3 (Bruker, 2018); cell refinement: SAINT (Bruker, 2018); data reduction: SAINT (Bruker, 2018);
program(s) used to solve structure: coordinates from previous refinement; program(s) used to refine structure: SHELXL
(Sheldrick, 2015); molecular graphics: ATOMS (Dowty, 2006); software used to prepare material for publication:
publCIF (Westrip, 2010).
Tin(IV) trioxidotellurate(IV)
Crystal data
SnTe3O8
Mr = 629.49
Cubic, Ia3
a = 11.1574 (4) Å
V = 1388.96 (15) Å3
Z = 8
F(000) = 2160
Dx = 6.021 Mg m−3
Mo radiation, λ = 0.71073 Å
Cell parameters from 5266 reflections
θ = 3.7–38.9°
µ = 16.04 mm−1
T = 296 K
Plate, light yellow
0.06 × 0.06 × 0.01 mm
Data collection
Bruker APEXII CCD
diffractometer
ω– and φ–scans
Absorption correction: multi-scan
(SADABS; Krause et al., 2015)
Tmin = 0.452, Tmax = 0.748
14087 measured reflections
735 independent reflections
697 reflections with I > 2σ(I)
Rint = 0.048
θmax = 40.2°, θmin = 3.7°
h = −18→20
k = −20→20
l = −19→20
Refinement
Refinement on F2
Least-squares matrix: full
R[F2 > 2σ(F2)] = 0.014
wR(F2) = 0.030
S = 1.07
735 reflections
21 parameters
0 restraints
w = 1/[σ2(Fo2) + (0.0127P)2 + 1.9293P]
where P = (Fo2 + 2Fc2)/3
(Δ/σ)max = 0.001
Δρmax = 1.27 e Å−3
Δρmin = −0.85 e Å−3
Extinction correction: SHELXL-2017/1
(Sheldrick 2015),
Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Extinction coefficient: 0.00046 (3)
supporting information
sup-2
Acta Cryst. (2021). E77
Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance
matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles;
correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate
(isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)
xyzU
iso*/Ueq
Sn1 0.000000 0.000000 0.000000 0.00501 (4)
Te1 0.20584 (2) 0.000000 0.250000 0.00804 (4)
O1 0.43242 (10) 0.13738 (10) 0.39972 (11) 0.0129 (2)
O2 0.16789 (10) 0.16789 (10) 0.16789 (10) 0.0078 (3)
Atomic displacement parameters (Å2)
U11 U22 U33 U12 U13 U23
Sn1 0.00501 (4) 0.00501 (4) 0.00501 (4) −0.00031 (3) −0.00031 (3) −0.00031 (3)
Te1 0.00518 (5) 0.01273 (6) 0.00620 (5) 0.000 0.000 −0.00229 (4)
O1 0.0095 (4) 0.0117 (4) 0.0174 (5) 0.0019 (3) 0.0018 (4) 0.0094 (4)
O2 0.0078 (3) 0.0078 (3) 0.0078 (3) 0.0020 (3) 0.0020 (3) 0.0020 (3)
Geometric parameters (Å, º)
Sn1—O1i2.0421 (11) Sn1—O1vi 2.0421 (11)
Sn1—O1ii 2.0421 (11) Te1—O1v1.8800 (11)
Sn1—O1iii 2.0421 (11) Te1—O1vii 1.8800 (11)
Sn1—O1iv 2.0421 (11) Te1—O2viii 2.1278 (3)
Sn1—O1v2.0421 (11) Te1—O2 2.1278 (3)
O1i—Sn1—O1ii 86.09 (4) O1iv—Sn1—O1vi 93.91 (4)
O1i—Sn1—O1iii 93.91 (4) O1v—Sn1—O1vi 86.09 (4)
O1ii—Sn1—O1iii 180.00 (9) O1v—Te1—O1vii 102.42 (8)
O1i—Sn1—O1iv 86.09 (4) O1v—Te1—O2viii 79.05 (4)
O1ii—Sn1—O1iv 93.91 (4) O1vii—Te1—O2viii 86.60 (6)
O1iii—Sn1—O1iv 86.09 (4) O1v—Te1—O2 86.60 (6)
O1i—Sn1—O1v93.91 (4) O1vii—Te1—O2 79.05 (4)
O1ii—Sn1—O1v86.09 (4) O2viii—Te1—O2 157.05 (6)
O1iii—Sn1—O1v93.91 (4) Te1ix—O1—Sn1x134.17 (6)
O1iv—Sn1—O1v180.00 (9) Te1—O2—Te1xi 117.94 (2)
O1i—Sn1—O1vi 180.00 (9) Te1—O2—Te1xii 117.94 (2)
O1ii—Sn1—O1vi 93.91 (4) Te1xi—O2—Te1xii 117.94 (2)
O1iii—Sn1—O1vi 86.09 (4)
Symmetry codes: (i) y, −z+1/2, x−1/2; (ii) −x+1/2, −y, z−1/2; (iii) x−1/2, y, −z+1/2; (iv) z−1/2, −x+1/2, −y; (v) −z+1/2, x−1/2, y; (vi) −y, z−1/2, −x+1/2;
(vii) −z+1/2, −x+1/2, −y+1/2; (viii) x, −y, −z+1/2; (ix) −y+1/2, −z+1/2, −x+1/2; (x) −x+1/2, −y, z+1/2; (xi) z, x, y; (xii) y, z, x.
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This book describes the bond valence model, a description of acid-base bonding which is becoming increasingly popular particularly in fields such as materials science and mineralogy where solid state inorganic chemistry is important. Recent improvements in crystal structure determination have allowed the model to become more quantitative. Unlike other models of inorganic chemical bonding, the bond valence model is simple, intuitive, and predictive, and can be used for analysing crystal structures and the conceptual modelling of local as well as extended structures. This is the first book to explore in depth the theoretical basis of the model and to show how it can be applied to synthetic and solution chemistry. It emphasizes the separate roles of the constraints of chemistry and of three-dimensional space by analysing the chemistry of solids. Many applications of the model in physics, materials science, chemistry, mineralogy, soil science, surface science, and molecular biology are reviewed. The final chapter describes how the bond valence model relates to and represents a simplification of other models of inorganic chemical bonding.