Largest perfluorometallate [Ti10F45]5- oligomer and polymeric ([Ti3F13]-)∞ and ([TiF5]-)∞ anions prepared as [XeF5]+ salts

Article abstract of DOI:10.1039/c6nj00955g

Reactions between XeF₂, TiF₄ and UV-irradiated elemental F₂ in anhydrous HF yielded XeF₅TiF₅ (XeF₆·TiF₄), [XeF₅]₅[Ti₁₀F₄₅] (XeF₆·2TiF₄), and [XeF₅][Ti₃F₁₃] (XeF₆·3TiF₄) upon crystallization. [XeF₅]₅[Ti₁₀F₄₅] crystallizes in two crystal modifications at low (α-phase, 150 K) and ambient (β-phase, 296 K) temperatures. The crystal structure determination of [XeF₅]₅[Ti₁₀F₄₅] reveals the largest known discrete decameric [Ti₁₀F₄₅]^5- anion built from ten TiF₆ octahedra, sharing vertices, in the shape of a double-star. [XeF₅]⁺ cations are completely ordered in the α-phase, while one of three crystallographically unique [XeF₅]⁺ cations is two-fold disordered in the β-phase. The anionic part of [XeF₅][Ti₃F₁₃] is built from tetrameric Ti₄F₂₀ and octameric Ti₈F₃₆ units sharing vertices and alternatively linked into ([Ti₃F₁₃]^-)_∞ columns. The charge balance is maintained by [XeF₅]⁺ cations which form secondary Xe?F contacts with fluorine atoms of ([Ti₃F₁₃]^-)_∞ groups. The main structural feature of XeF₅TiF₅ is an infinite chain of distorted TiF₆ octahedra joined by cis vertices.

Full text of DOI:10.1039/c6nj00955g

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Largest perfluorometallate [Ti10F45]5À oligomer
and polymeric ([Ti3F13]À)N and ([TiF5]À)N anions
prepared as [XeF5]+ salts†
Cite this:DOI: 10.1039/c6nj00955g
Zoran Mazej* and Evgeny A. Goreshnik
Reactions between XeF2, TiF4 and UV-irradiated elemental F2 in anhydrous HF yielded XeF5TiF5
(XeF6ÁTiF4), [XeF5]5[Ti10F45] (XeF6Á2TiF4), and [XeF5][Ti3F13] (XeF6Á3TiF4) upon crystallization. [XeF5]5[Ti10F45
]
crystallizes in two crystal modifications at low (a-phase, 150 K) and ambient (b-phase, 296 K) temperatures.
The crystal structure determination of [XeF5]5[Ti10F45] reveals the largest known discrete decameric
5À
anion built from ten TiF6 octahedra, sharing vertices, in the shape of a double-star. [XeF5]+
[Ti10F45
]
cations are completely ordered in the a-phase, while one of three crystallographically unique [XeF5]+
cations is two-fold disordered in the b-phase. The anionic part of [XeF5][Ti3F13] is built from tetrameric
Ti4F20 and octameric Ti8F36 units sharing vertices and alternatively linked into ([Ti3F13]À)N columns. The
charge balance is maintained by [XeF5]+ cations which form secondary XeÁ Á ÁF contacts with fluorine
atoms of ([Ti3F13]À)N groups. The main structural feature of XeF5TiF5 is an infinite chain of distorted TiF6
octahedra joined by cis vertices.
Received (in Montpellier, France)
26th March 2016,
Accepted 31st May 2016
DOI: 10.1039/c6nj00955g
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and it is rarely the coordination number which changes. The
[Mn+F6]6Àn octahedra are forced to share their F ligands instead of
Introduction
The structural chemistry of inorganic fluorine compounds is being isolated. The crystal structures of the fluorido titanates(IV)
dominated by the simple electrostatic and geometrical principles illustrate well the diversity of the possible structural motifs from
for which the coordination number of six with an octahedral the 0D (zero dimensional monomeric [TiF6]2À and oligomeric
coordination is favoured for nearly all transition metals (M).1,2 anions) to the 1D (chains, columns) and 2D architectures
Such a coordination is quite unaffected by the M :F stoichiometry (layers).4 In recent years, many new oligomeric fluorido Ti(IV)
of the compound or by the oxidation state of the metal. Excep- anions were prepared and characterized, i.e. [Ti4F19]3À, [Ti4F20]4À
tions involve metal cations of heavier elements (e.g., Zr, Hf), [Ti5F23]3À, [Ti8F36]4À, etc.5–7
,
which prefer higher coordination than six, and metal cations
XeF6 acts as a single fluoride ion donor forming [XeF5]+ or
with d8 and d9 electronic configurations, which are often found [Xe2F11]+ salts with various binary fluorides.8–10 The majority
in the square-planar coordination.1 In fluorides, the condensa- of the structural studies were conducted for the products of
tions of [Mn+F6]nÀ6 octahedra via vertices are favoured in contrast reactions between XeF6 and MF5 (M = V, Nb, Au, Ru, Pt, As, Sb),
to the higher halogen homologs where associations via edges or which are well soluble in anhydrous hydrogen fluoride (aHF) and
faces are more common.3 What if the ratio F :M is smaller than therefore single crystals are easily grown. The isolated solids
six? The metal centers prefer the coordination of six F ligands consist of [XeF5]+ or [Xe2F11]+ cations and [MF6]À or [M2F11]À
anions (depending on the XeF6 :MF5 molar ratio). Lower fluorides,
ˇ
Department of Inorganic Chemistry and Technology, Jozef Stefan Institute, Jamova 39,
1000 Ljubljana, Slovenia. E-mail: zoran.mazej@ijs.si; Tel: +386 1 477 3301
† Electronic supplementary information (ESI) available: Phases observed upon the
crystallizations and reactions of different XeF2 : TiF4 ratios (Table S1); the com-
such as MF3 and MF4, are usually polymeric and poorly or
insoluble in aHF. Well characterized are the products in the
XeF6/CrF4 system11,12 and a few compounds in XeF6/MF4
(M = Ni, Pd and Ge) and XeF6/MF3 (M = Ag, Au and B)8–10
systems. Reactions between XeF6 and MF4 in the 4 : 1 and
plete list of vibrational frequencies of XeF5TiF5, [XeF5]5[Ti10F45] and [XeF5][Ti3F13
]
(Table S2) and selected Raman spectra and X-ray powder diffraction patterns
(Fig. S1–S10) of the solids obtained after the UV-irradiated F2 reactions and 2 : 1 molar ratios always result in [MF6]2À salts of [Xe2F11]+
crystallizations of various XeF2 : TiF4 starting ratios; packing of infinite ([Ti3F13]À)N
or [XeF5]+.8–10 More interesting are the other ratios where
columns and [XeF5]+ cations in [XeF5]3[Ti3F13] (Fig. S11). Further details of the
anions with different geometries could be expected. For example,
crystal structure investigations may be obtained from FIZ Karlsruhe, 76344
3XeF6Á4TiF4 consists of [XeF5]+ and discrete tetrameric [Ti4F19]3À
Eggenstein-Leopoldshafen, Germany, upon quoting the deposition numbers,
anions.5 The reports about XeF6/MF4 (M = Ti, Mn, Pb, Sn, Zr, Hf)
CSD-431029 (b-[XeF5]5[Ti10F45]), CSD-431031 ([XeF5][Ti3F13]) and CSD-431030
(XeF5TiF5). See DOI: 10.1039/c6nj00955g
phases are limited to the determination of their compositions
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with the mass balance and elemental chemical analysis and to BXFM-ILHS microscope. Samples were excited by 632.8 nm
the characterizations using primarily vibrational spectroscopy.8–10 emission line of a He–Ne laser with a power of 20 mW which
In a short communication, published in 1976, three com- equals the power of 17 mW focused to a 1 mm spot through a
pounds described as 4XeF6ÁTiF4, XeF6ÁTiF4 and XeF6Á2TiF4 were 50Â microscope objective onto the top surface of the sample.
reported.13 Their compositions were determined with the help of Raman spectra of XeF5TiF5, [XeF5]5[Ti10F45] and [XeF5][Ti3F13]
elemental chemical analysis and compounds were investigated were acquired on randomly orientated single crystals. All crystals
using IR spectroscopy and magnetic susceptibility measurements. were first checked on a diffractometer.
In 2009, the synthesis of [XeF5]3[Ti4F19] (i.e. 3XeF6Á4TiF4), prepared
Synthetic procedures
by the reaction between XeF2, TiF4 and UV-irradiated elemental
fluorine in aHF, was reported.5
Attempted synthesis of individual XeF6/TiF4 phases in larger
Reactions between XeF2, TiF4 and UV-irradiated F2 in aHF quantities and crystal growths. Various amounts of XeF2 and
with the different starting XeF2/TiF4 molar ratios yielded TiF4 (totaling ca. 150 mg) were loaded into the reaction vessel
XeF6ÁTiF4, XeF6Á2TiF4, and XeF6Á3TiF4 upon crystallization. inside a drybox (Table S1, ESI†). aHF (6–10 ml) was condensed
Their crystal structure determinations showed that they can onto the solid at 77 K and the reaction mixture was brought to
be formulated as XeF5TiF5, [XeF5]5[Ti10F45] and [XeF5][Ti3F13]. ambient temperature. Fluorine was slowly added at ambient
The results are described in the present paper.
temperature to a pressure of 4–6 bar in the reaction vessel.
A medium pressure mercury lamp (Hg arc lamp, 450 W, Ace
Glass, USA) was used as the UV source. The reaction mixture
was left stirring for 10–20 days at ambient temperature. Clear
colourless solutions were obtained. All volatiles were slowly
pumped off at ambient temperature leaving behind colourless
solids. After characterization, powdered products were transferred
to the crystallization vessels where aHF (6–10 ml) was condensed
onto the starting material at 77 K. The crystallization mixture was
warmed to ambient temperature and the resulting clear, colorless
solution was decanted into the 6 mm o.d. side arm. Evaporation
of the solvent from this solution was carried out by maintaining a
Experimental
Caution: Anhydrous HF and some fluorides are highly toxic and
must be handled in a well-ventilated hood and protective
clothing must be worn at all times! XeF6 and all of its products
are susceptible to moisture and react with water forming shock-
sensitive XeO3, a compound that detonates easily.
Materials and methods
Reagents. Fluorine was obtained from Solvay Fluor und temperature gradient of ca. 10–20 1C between both tubes for
Derivate GmbH, Hannover, Germany, and aHF was obtained several weeks. Slow distillation of aHF from the 6 mm o.d. tube
from Linde AG, Puliach, Germany. Titanium tetrafluoride was into the 19 mm o.d. tube resulted in crystal growth inside the
synthesized by the reaction of TiCl3 (Sigma-Aldrich, 99.999%) 6 mm o.d. tube.
with elemental fluorine F2 in aHF. Purity of TiF4 was confirmed
Several solutions of dissolved products, prepared from nXeF2/
using Raman spectroscopy and elemental chemical analysis. TiF4/UV-irradiated F2/aHF mixtures in crystallization vessels, were
Xenon difluoride was prepared by photochemical reaction between left to crystallize without prior isolation and characterization.
Xe and F2 at ambient temperature.14
Crystallography
Synthetic apparatus. All manipulations were carried out under
anhydrous conditions. The volatile compounds, such as aHF and Crystals were immersed in perfluorodecalin (ABCR, 98%) inside
F2, were handled on a vacuum line constructed from nickel- a drybox, selected under a microscope, and mounted on the
Teflon and the non-volatile materials were handled in a drybox goniometer head of the diffractometer in a cold nitrogen stream.
(M. Braun) in an argon atmosphere (o0.5 pmm H2O). Syntheses Selected single crystals were transferred to 0.3 mm quartz capil-
were done in reaction vessels made of FEP (tetrafluoroethylene- laries inside the dry box and their Raman spectra were recorded
hexafluoropropylene block copolymer; Polytetra GmbH, Germany) at several random positions. Crystals sealed in quartz-glass
tubes (16 mm i.d. Â 19 mm. o.d.). Single crystals of XeF6/TiF4 capillaries were also used for structural determination at ambient
phases were grown in T-shaped crystallization vessels that com- temperature.
prised two FEP tubes (one 16 mm i.d. Â 19 mm. o.d. and the other
Single-crystal data for all the compounds were collected on a
4 mm i.d. Â 6 mm. o.d.). Each tube was heat-sealed on one end Gemini A diffractometer equipped with an Atlas CCD detector,
and joined at 901 through a Teflon T-connector. A PTFE valve was using graphite monochromated Mo–Ka radiation. Data were
connected at 1801 to the 19 mm o.d. tube. Before use, the above- treated using the CrysAlisPro software suite program package.15
mentioned reaction and crystallization vessel assemblies were Analytical absorption corrections were applied to all the data
dried under dynamic vacuum and passivated with elemental sets. Crystal structures of b-[XeF5]5[Ti10F45], [XeF5][Ti3F13], and
fluorine at 1 bar for few hours. Anhydrous HF (Linde, 99.995%) XeF5TiF5 were solved with the direct methods using the SHELXS
was treated with K2NiF6 (Advance Research Chemicals, Inc.) for program.16 Structure of a-[XeF5]5[Ti10F45] was solved with the
several hours prior to use.
charge-flipping method using the Superflip program17 (Olex
Instrumentation. Raman spectra with a resolution 0.5 cmÀ1 crystallographic software18). The electron density map, obtained
were recorded at room temperature on a HORIBA JOBIN with Superflip software, was analyzed using the EDMA program,19
YVON LabRam-HR spectrometer equipped with an Olympus which gave an initial model of the structure. Structure refinement
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Table 1 Crystal data and refinement results for a-[XeF5]5[Ti10F45], b-[XeF5]5[Ti10F45], [XeF5][Ti3F13], and XeF5TiF5 arising from XeF2/TiF4/UV-irradiated F2
systems
Chemical formula
b-[XeF5]5[Ti10F45
]
a-[XeF5]5[Ti10F45
]
[XeF5][Ti3F13
]
XeF5TiF5
FW (g molÀ1
Space group
a (Å)
b (Å)
c (Å)
)
2465.04
Cmc21
18.8980(4)
16.7388(4)
17.3542(4)
90
90
90
5489.7(2)
4
2.9595
296
2465.04
Cc
18.9017(6)
16.6334(5)
17.3336(5)
90
94.004(3)
90
5436.4(3)
4
3.0117
150
0.0886
0.2682
1.064
616.9
P1
369.16
Pbca
18.139(2)
8.5173(9)
18.1876(16)
90
90
90
2810.0(5)
16
3.491
%
9.7699(6)
11.0276(6)
13.4581(7)
89.601(5)
69.992(5)
77.717(5)
1327.82(14)
4
3.0857
150
0.0579
0.1540
a (1)
b (1)
g (1)
V (Å3)
Z
Dcalc (g cmÀ3
T (K)
)
150
a
R1
0.0350
0.0857
1.043
2.306, À1.459
0.0867
0.2289
1.054
7.688, À3.278
b
wR2
GOFc
1.001
4.392, À1.768
Drmax,min (e ÅÀ3
)
5.962, À4.831
P
P
P
P
P
a
b
2
c
2
R1 is defined as ||Fo| À |Fc|| |Fo|for I 4 2s(I). wR2 is defined as [ [w(Fo À Fc2)2]/ w(Fo2)2]1/2 for I 4 2s(I). GOF = [ [w(Fo À Fc2)2]/(No À Np)]1/2
,
where No = number of reflections and Np = number of refined parameters.
was performed using SHELXL-201420 software, implemented detected in all isolated solids. Upon crystallization of the product
in the program package WinGX.21 Figures were prepared using of 1 : 2 reaction, single crystals of [XeF5]3[Ti4F19], [XeF5]5[Ti10F45], and
DIAMOND 3.2 software.22 The corresponding crystal data and [XeF5][Ti3F13] were grown in the same batch. Raman spectra showed
refinement results are summarized in Table 1.
also the presence of TiF4. Higher amounts of TiF4 (1:3, 1:4) always
Numerous repeated attempts to improve the quality of yielded mixtures of [XeF5][Ti3F13] and TiF4, or sometimes even of
structural data of a-[XeF5]5[Ti10F45] were performed. The main (O2)Ti7F30,24 due to the moisture contamination and formation of
+
problem was reproducible Cmc21 - Cc transformation accom- O2 during the UV-reactions.
panying a change in single to twinned crystals that happened
The particular emphasis was given on the preparation of
during b-[XeF5]5[Ti10F45] to a-[XeF5]5[Ti10F45] phase transition. [XeF5]5[Ti10F45] and [XeF5][Ti3F13] in bulk quantities. Unfortunately,
Additionally, even after very slow and long-term crystal cooling the products of reactions between XeF2/nTiF4/UV-irradiated F2
from 296 K to 150 K, the diffraction pattern still contained (n = 2, 3) were of so poor crystallinity that the obtained X-ray
nearly 30% reflections belonging to the b-phase. Overlapping of diffraction patterns were practically useless (Fig. S8–S10, ESI†).
the reflections of both a-phase domains and of the reflections Very broad bands were observed in the Raman spectrum of the
of the remains of the b-phase was the main reason for the very XeF6/3TiF4 product (Fig. S2, ESI†), while the Raman spectrum of
poor quality of a-[XeF5]5[Ti10F45] structural data.
the XeF6/2TiF4 product didn’t match with that of [XeF5]5[Ti10F45]
measured on a single crystal (Fig. S1, ESI†).
Raman spectroscopy has found to be the most appropriate
method for the identification of various perfluorotitanate(IV)
phases obtained during the syntheses or upon the crystallizations.
With the exception of [TiF6]2À, the Raman bands of symmetric
in-phase Ti–Ft stretching modes are found in the 700–800 cmÀ1
region6,7 and therefore they do not overlap with vibrational modes
of [XeF5]+ cations.5 The frequency of the band increases with
increasing TiF4 content and decreasing anion charge. Corres-
ponding bands were observed at 733 cmÀ1 for XeF5TiF5, at
742 cmÀ1 for [XeF5]3[Ti4F19],5 at 780 cmÀ1 for [XeF5]5[Ti10F45]
and at 784 cmÀ1 for [XeF5][Ti3F13] (Fig. 1 and Table S2, ESI†).
In the Raman spectra of (O2)2(Ti7F30) and TiF4 they are found at
768 cmÀ1 and 805 cmÀ1, respectively.7,24
Results and discussion
Synthesis
With the exception of [XeF5]3[Ti4F19],5 which can be synthesized
from the n(XeF2) : n(TiF4) = 3 : 4 starting mixture with the use
of UV-irradiated F2, all other combinations led to mixtures of
various compounds (Table S1, Fig. S3–S7, ESI†). The same
happened upon the crystallizations. With a larger amount of
XeF2 (n(XeF2) : n(TiF4) = 1 : 1, 1.5 : 1, 2 : 1, 3 : 1, 4 : 1), XeF5TiF5
was observed in all isolated solids and [XeF5]3[Ti4F19] in the
majority of them (Table S1, ESI†). Products of 2 : 1, 3 : 1 and
4 : 1 reactions contained also some XeF4. Reactions between
XeF2 and various binary fluorides (MFx) in the presence of
UV-irradiated F2 in aHF proceed to [XeF5]+ or [Xe2F11]+ salts.
Without the presence of MFx the oxidation (fluorination) of
Crystal structures
XeF2 takes place only to form XeF4.23 The same happens if more [XeF5]5[Ti10F45] crystallizes in two crystal modifications at low
XeF2 is available than requested for the formation of nXeF6ÁMFx (a-phase, 150 K) and ambient (b-phase, 296 K) temperatures.
where the highest value of n depends on the capability of parti- b-[XeF5]5[Ti10F45] crystallizes in the orthorhombic space group
cular MFx.8–10 When the amount of TiF4 was increased above Cmc21 with unit cell parameters a = 18.8980(4) Å, b = 16.7388(4) Å,
a 1 : 1.33 (3 : 4) ratio (i.e. 1 : 2, 1 : 3, 1 : 4), [XeF5][Ti3F13] was c = 17.3542(4) Å, V = 5489.7(2) Å3, Z = 4. Crystal structures of
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Fig. 1 Raman spectra of XeF5TiF5, [XeF5]5[Ti10F45], and [XeF5][Ti3F13] recorded
at room temperature on randomly orientated single-crystals.
b-[XeF5]5[Ti10F45] consists of [XeF5]+ cations and largest observed
discrete perfluometallate decameric [Ti10F45]5À anions constructed
from ten TiF6 octahedral units (Fig. 2 and 3). Previously, the largest
examples were octameric [Ti8F36]4À and [Al8F35]11À 7,25
Each of
.
ten TiF6 octahedra shares three fac-vertices with adjacent TiF6
units resulting in a double star-like geometry of the [Ti10F45]5À
anion (Fig. 2).
5À
Fig. 3 Packing of [XeF5]+ cations and [Ti10F45
]
anions in the crystal
structure of b-[XeF5]5[Ti10F45]. The disorder of [XeF5]+ cations is omitted
There are six crystallographically independent Ti atoms
in the unit cell of b-[XeF5]5[Ti10F45]. The length distribution of
Ti–Ft (Ft = terminal F atom) and Ti–Fb (Fb = bridging F atom)
falls in the range of 1.728(7)–1.823(6) Å and 1.916(6)–2.006(6) Å,
respectively. The [Ti10F45]5À anion is coordinated to five [XeF5]+
cations (Fig. 2) through the sixteen XeÁ Á ÁF secondary contacts
(2.492(6)–2.848(7) Å). Each of the three [XeF5]+ cations forms
four secondary contacts with the same [Ti10F45]5À anion, mean-
while two [XeF5]+ cations are coordinated to two [Ti10F45]5À
anions with two secondary contacts with each of them. The
low temperature phase a-[XeF5]5[Ti10F45] is monoclinic (Cc) at
150 K with a = 18.9017(6) Å, b = 16.6334(5) Å, c = 17.3336(5) Å,
for clarity.
b = 94.004(3)1, V = 5436.4(3) Å3, Z = 4. Unfortunately, even after
multiple and repeated attempts, the quality of collected X-ray
diffraction data was very low. Therefore, this structure is not
further discussed. The main difference between both [Ti10F45]5À
phases is that [XeF5]+ cations are completely ordered in the a-phase,
while one of the three crystallographically unique [XeF5]+ cations is
two-fold disordered in the b-phase.
The second crystalline phase, obtained during this work,
corresponds to the molar ratio XeF6:TiF4 = 1:3, i.e. [XeF5][Ti3F13]. The
anionic part is built from tetrameric Ti4F20 and octameric Ti8F36
units sharing vertexes and alternatively linked into ([Ti3F13]À)N
columns (Fig. 4 and 5, and Fig. S11, ESI†). The negative charge of
the anions is balanced with [XeF5]+ counter cations interacting with
secondary XeÁ Á ÁF bonds. At 150 K, [XeF5][Ti3F13] crystallizes in
%
the triclinic P1 space group with a = 9.7699(6) Å, b = 11.0276(6) Å,
c = 13.4581(7) Å, a = 89.601(5)1 b = 69.992(5)1, g = 77.717(5)1,
V = 1327.82(14) Å3 and Z = 4. The Ti–Ft bond lengths range from
1.728(5) to 1.813(5) Å and are significantly shorter than the
Ti–Fb bonds (1.942(4)–2.049(5) Å).
The largest proportion of [XeF5]+ cations is observed in XeF6ÁTiF4
(XeF5TiF5). This phase was detected in the majority of the samples
prepared by molar ratios XeF6 : TiF4 4 1 (Table S1, ESI†). Very
small, needle-like, single crystals were always grown. The numerous
repeated attempts to obtain the good-quality X-ray diffraction
data were unsuccessful. The structure refinement did not lead
to the satisfactory results. Because of the unresolvable twinning,
the R factors of the final model were very high and large residual
electron-density maxima were found at the physically unreason-
able positions. Therefore, the given structure is to be understood
Fig. 2 [XeF5]+ cations and [Ti10F45
in b-[XeF5]5[Ti10F45] (ellipsoids are drawn at 50% probability).
]
5À anions, composed of ten TiF6 octahedra,
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to XeF5CrF5.12 The crystal structure consists of infinite ([TiF5]À)N
chains built of TiF6 octahedra sharing cis-vertices (Fig. 6). This is
in contrast to ([TiF5]À)N chains in H3OTiF5 and NH4TiF5 where
TiF6 octahedra share fluorine atoms in trans-positions.26,27
Conclusions
Reactions between the various ratios of XeF2 and TiF4 in the
presence of UV-irradiated F2 in aHF confirmed the existence of
two previously reported phases, i.e. XeF6ÁTiF4 and XeF6Á2TiF4.13
With the applied UV-synthesis it is not possible to prepare and
confirm the existence of 4XeF6ÁTiF4.13 Since this phase most
likely corresponds to [Xe2F11]2[TiF6] no further attempts were
made to prepare it by reaction between a large excess of XeF6
and TiF4.13 The UV-approach resulted in two new phases, i.e.
Fig. 4 Part of the infinite ([Ti3F13]À)N column in [XeF5][Ti3F13] (ellipsoids
are drawn at 50% probability).
5
3XeF6Á4TiF4 and XeF6Á3TiF4.
XeF6ÁTiF4, XeF6Á2TiF4 and XeF6Á3TiF4 are more correctly
described as XeF5TiF5, [XeF5]5[Ti10F45] and [XeF5][Ti3F13]. The
crystal structure of [XeF5]5[Ti10F45] consists of [XeF5]+ cations
and the largest known example of discrete oligomeric perfluor-
ometallate [Ti10F45]5À anions. This new anion has taken the
crown from [Al8F35]11À and [Ti8F36]4À, previous examples with
the highest rate of association of [Mn+F6]nÀ6 octahedra.7,25 Also
in the case of heavier transition metals (Zr, Hf, etc.), where the
coordination numbers higher than six are more common,
no such large oligomeric perfluorometallate species have been
reported so far.
Acknowledgements
The authors gratefully acknowledge the Slovenian Research
Agency (ARRS) for financial support of the present work. They
are also very grateful to Prof. Florian Kraus for measuring the
X-ray powder diffraction patterns.
Fig. 5 Packing of ([Ti3F13]À)N columns and [XeF5]+ cations in the crystal
structure of [XeF5][Ti3F13].
as merely modelling connectivity. The best result was obtained
for a small crystal (max size 0.17 mm, mid size 0.035 mm,
min size 0.028) for which data were collected over 120 hours.
XeF5TiF5 crystallizes in the orthorhombic Pbca space group
with unit cell parameters a = 18.139(2) Å, b = 8.5173(9) Å,
c = 18.1876(16) Å, V = 2810.0(5) Å3 and Z = 16, and it is isostructural
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