Crystal structure and proton conductivity of a new Cs3(H2PO4)(HPO4)·2H2O phase in the caesium di- and monohydrogen orthophosphate system

Article abstract of DOI:10.1107/S2053229617012335

The M_xH_y(AO₄)_z acid salts (M = Cs, Rb, K, Na, Li, NH₄; A = S, Se, As, P) exhibit ferroelectric properties. The solid acids have low conductivity values and are of interest with regard to their thermal properties and proton conductivity. The crystal structure of caesium dihydrogen orthophosphate monohydrogen orthophosphate dihydrate, Cs₃(H_1.5PO₄)₂·2H₂O, has been solved. The compound crystallizes in the space group Pbca and forms a structure with strong hydrogen bonds connecting phosphate tetrahedra that agrees well with the IR spectra. The dehydration of Cs₃(H_1.5PO₄)₂·2H₂O with the loss of two water molecules occurs at 348-433K. Anhydrous Cs₃(H_1.5PO₄)₂ is stable up to 548K and is then converted completely into caesium pyrophosphate (Cs₄P₂O₇) and CsPO₃. Anhydrous Cs₃(H_1.5PO₄)₂ crystallizes in the monoclinic C2 space group, with the unit-cell parameters a = 11.1693(4), b = 6.4682(2), c = 7.7442(3)? and β = 71.822(2)°. The conductivities of both compounds have been measured. In contrast to crystal hydrate Cs₃(H_1.5PO₄)₂·2H₂O, the dehydrated form has rather low conductivity values of 6 × 10^-6-10^-8 S cm^-1 at 373-493K, with an activation energy of 0.91 eV.

Full text of DOI:10.1107/S2053229617012335

research papers
Crystal structure and proton conductivity of a new
Cs3(H2PO4)(HPO4)ꢁ2H2O phase in the caesium di-
and monohydrogen orthophosphate system
ISSN 2053-2296
Valentina Ponomareva,a,b* Irina Bagryantseva,a,b Boris Zakharov,a,b Natalia
Bulina,a Galina Lavrovaa and Elena Boldyrevaa,b
Received 10 July 2017
aInstitute of Solid State Chemistry and Mechanochemistry SB RAS, Kutateladze 18, Novosibirsk 630128, Russian
Federation, and bNovosibirsk State University, Pirogova 2, Novosibirsk 630090, Russian Federation. *Correspondence
e-mail: ponomareva@solid.nsc.ru
Accepted 24 August 2017
Edited by P. Fanwick, Purdue University, USA
The MxHy(AO4)z acid salts (M = Cs, Rb, K, Na, Li, NH4; A = S, Se, As, P) exhibit
ferroelectric properties. The solid acids have low conductivity values and are of
interest with regard to their thermal properties and proton conductivity. The
crystal structure of caesium dihydrogen orthophosphate monohydrogen
orthophosphate dihydrate, Cs3(H1.5PO4)2ꢁ2H2O, has been solved. The com-
pound crystallizes in the space group Pbca and forms a structure with strong
hydrogen bonds connecting phosphate tetrahedra that agrees well with the IR
spectra. The dehydration of Cs3(H1.5PO4)2ꢁ2H2O with the loss of two water
molecules occurs at 348–433 K. Anhydrous Cs3(H1.5PO4)2 is stable up to 548 K
and is then converted completely into caesium pyrophosphate (Cs4P2O7) and
CsPO3. Anhydrous Cs3(H1.5PO4)2 crystallizes in the monoclinic C2 space group,
Keywords: acid salt; proton conductivity;
caesium dihydrogen phosphate; orthophos-
phate; crystal structure; ferroelectric properties;
thermal properties; mechanochemistry.
CCDC reference: 1555937
Supporting information: this article has
supporting information at journals.iucr.org/c
˚
with the unit-cell parameters a = 11.1693 (4), b = 6.4682 (2), c = 7.7442 (3) A and
ꢀ = 71.822 (2)ꢂ. The conductivities of both compounds have been measured. In
contrast to crystal hydrate Cs3(H1.5PO4)2ꢁ2H2O, the dehydrated form has rather
low conductivity values of ꢃ6 ꢄ 10ꢅ6–10ꢅ8 S cmꢅ1 at 373–493 K, with an
activation energy of 0.91 eV.
1. Introduction
The family of acid salts with the general structural formula
MxHy(AO4)z (M = Cs, Rb, K, Na, Li, NH4; A = S, Se, As, P) has
been studied intensively due to their ferroelectric properties,
which are promising for optical devices (Busch & Scherrer,
1935; Frazer & Pepinsky, 1953; Reese & May, 1967; Busch,
1987). The solid acids have low conductivity values (ꢃ10ꢅ6
–
10ꢅ9 S cmꢅ1 at room temperature) which are associated with
proton hopping in the crystal structures with ordered
hydrogen bonds related to the presence of local defects.
Superionic phase transitions with a significant entropy change
were detected in these systems in the 1980s and 1990s. High-
temperature superionic phases are characterized by structural
disordering of the hydrogen-bond network, resulting in high
mobility of the protons and an increase in the proton
conductivity up to ꢁ ꢃ 10ꢅ3–10ꢅ2 S cmꢅ1 at 373–523 K
(Baranov et al., 1982, 1988; Preisinger et al., 1994).
Caesium dihydrogen phosphate in its superionic phase has
one of the highest conductivity values among the numerous
salts of the family (Preisinger et al., 1994). A phase transition
from the monoclinic (P21/m) to the superionic cubic (Pm3m)
phase of CsH2PO4 is observed at 502 K. In the superionic
phase, all H+ ions participate in proton transfer, accounting for
the high conductivity value, ꢁ503 K = 6 ꢄ 10ꢅ2 S cmꢅ1 (Prei-
singer et al., 1994). Due to the high proton conductivity,
# 2017 International Union of Crystallography
Acta Cryst. (2017). C73
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CsH2PO4 is promising as a material for proton membranes in
electrochemical devices, in particular, in intermediate-
temperature fuel cells (ITFCs). High electrochemical char-
acteristics have been achieved for ITFCs with the CsH2PO4
membrane (Boysen et al., 2004; Uda & Haile, 2005). For the
disubstituted phosphate analogue, i.e. Cs2HPO4ꢁ2H2O, the
crystal structure, thermal properties and conductivity have
Table 1
Experimental details.
Crystal data
Chemical formula
Mr
Crystal system, space group
Temperature (K)
˚
a, b, c (A)
Cs3(H2PO4)(HPO4)ꢁ2H2O
627.73
Orthorhombic, Pbca
296
7.4721 (5), 11.4369 (8),
14.8509 (11)
1269.12 (15)
4
Mo Kꢂ
8.85
¨
been reported recently (Stoger & Weil, 2014; Lavrova et al.,
3
˚
V (A )
2016; Ponomareva et al., 2017). Cs2HPO4ꢁ2H2O crystallizes in
Z
Radiation type
the monoclinic space group P21/c, with lattice parameters a =
ꢂ
ꢃ (mmꢅ1
Crystal size (mm)
)
˚
˚
˚
7.4761 A, b = 14.2125 A, c = 7.9603 A, ꢀ = 116.914 , V =
0.20 ꢄ 0.05 ꢄ 0.02
3
754.20 A and Z = 4. The distorted tetrahedra of the HPO4
2ꢅ
˚
˚
Data collection
Diffractometer
anions are linked by short hydrogen bonds (Oꢁ ꢁ ꢁO = 2.579 A),
forming a chain along the c axis. Two symmetry-independent
water molecules connect the chains into a three-dimensional
Agilent Xcalibur Ruby Gemini
ultra
Absorption correction
Multi-scan (CrysAlis PRO; Rigaku
OD, 2016)
0.453, 1.000
˚
hydrogen-bonding network (Oꢁ ꢁ ꢁO = 2.740–2.753 A). Cs2-
Tmin, Tmax
HPO4ꢁ2H2O dehydrates in two stages with losses of 0.5 and 1.5
water molecules per asymmetric unit at temperatures of 333–
373 and 373–433 K, respectively. Anhydrous Cs2HPO4 is
stable up to 673 K; at 603 K, it is completely converted to
caesium pyrophosphate, Cs4P2O7 (Lavrova et al., 2016).
The conductivity measurements for Cs2HPO4ꢁ2H2O agree
with the thermogravimetry and IR spectroscopy data (Pono-
mareva et al., 2017). The proton conductivity of Cs2HPO4
(ꢃ6 ꢄ 10ꢅ6–10ꢅ9 S cmꢅ1 at 363–523 K) is comparable with the
values for the low-temperature phase of CsH2PO4. Investi-
gation of the (1 ꢅ x)CsH2PO4–xCs2HPO4ꢁyH2O system in a
wide range of compositions allowed us to find Cs3-
(H1.5PO4)2ꢁyH2O, a previously unreported phase at x = 0.5.
The existence of this phase affects markedly the transport and
thermodynamic properties of the composite proton electro-
lytes based on these salts.
No. of measured, independent and
observed [I > 2ꢁ(I)] reflections
Rint
17880, 1298, 1176
0.086
0.625
ꢅ1
˚
(sin ꢄ/ꢅ)max (A
)
Refinement
R[F2 > 2ꢁ(F2)], wR(F2), S
No. of reflections
0.030, 0.074, 1.05
1298
79
1
Only H-atom coordinates refined
No. of parameters
No. of restraints
H-atom treatment
ꢅ3
˚
Áꢆmax, Áꢆmin (e A
)
0.85, ꢅ1.14
Computer programs: CrysAlis PRO (Rigaku OD, 2016), SHELXS97 (Sheldrick, 2008),
SHELXL2016 (Sheldrick, 2015), shelXle (Hu¨bschle et al., 2011) and DIAMOND
(Brandenburg & Putz, 1999).
The present work aims to study the crystal structure of the
new Cs3(H1.5PO4)2ꢁyH2O compound in relation to its thermal
properties and proton conductivity.
2. Experimental
2.1. Synthesis and crystallization
Single crystals of the starting Cs2HPO4ꢁ2H2O and CsH2PO4
compounds were grown by isothermal evaporation at 308 K
and at room temperature from aqueous solutions of Cs2CO3
(special purity grade) and H3PO4 (special purity grade) taken
in molar ratios of 1:1 and 1:2, respectively. Single crystals of
Cs3(H1.5PO4)2ꢁyH2O were grown in a similar way, i.e. by the
isothermal evaporation of aqueous solutions of Cs2HPO4ꢁ-
2H2O and CsH2PO4 taken in an equimolar ratio at 308 K.
2.2. PXRD and EDS analysis
The phase composition of the parent salts was investigated
by powder X-ray diffraction (PXRD). PXRD patterns were
collected on a Bruker D8 Advance diffractometer with Cu Kꢂ
radiation (one-dimensional Lynx-Eye detector and Kꢀ filter).
The PXRD patterns of the initially synthesized salts are
¨
completely in agreement with previous results (Stoger & Weil,
2014; Lavrova et al., 2016; Ueso & Kobayashi, 1976; Matsu-
naga et al., 1980; Preisinger et al., 1994). The ratio of caesium
to phosphorus in the crystals was estimated by energy-
Figure 1
Electron microscopy photograph (top) and EDS spectrum (bottom) of
the Cs3(H1.5PO4)2ꢁ2H2O single crystal.
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dispersive X-ray spectroscopy (EDS) using a Thermo Scien-
tific EDS Spectrometer with a Silicon Drift UltraDry 30
detector on a Hitachi 3400N scanning electron microscope.
The EDS spectra were processed using the Thermo Scientific
NSS software package. An analysis of the spectrum showed
the content of Cs atoms in the synthesized compound to be 1.5
times higher than the content of P atoms (Fig. 1), corre-
sponding to the Cs3(H1.5PO4)2ꢁ2H2O formula. The content of
crystal water in a single crystal was estimated from the
thermogravimetric data. IR absorption spectra of the powders
were registered using a Digilab Excalibur 3100 spectrometer
parameters for Cs3(H1.5PO4)2 were carried out from the PXRD
pattern created by the TOPAS software (Coelho et al., 2011).
2.4. Conductivity measurements
For conductivity measurements, the samples were pressed
with silver electrodes into pellets (diameter 7 mm, thickness
ꢃ2.3 mm), with a relative density of 96–98%. The conductivity
was measured in the frequency range 1–3.3 MHz by a two-
electrode circuit alternating current impedance meter IPU-
1RLC-1/2008, an instrument for the precise measurements of
electrochemical characteristics developed by the Institute of
Control Sciences of the Russian Academy of Sciences. The
higher frequency minimum/intercept along the x axis (real Z)
of the impedance plots was used to calculate the bulk resis-
with a ZnSe crystal in the frequency range 4000–600 cmꢅ1
.
Differential scanning calorimetry (DSC) and thermo-
gravimetry (TGA) data were obtained using a NETZSCH
STA 449 F/1/1 JUPITER thermoanalytical complex in the
temperature range 293–713 K at a heating rate of 2 K minꢅ1
under argon with a flow rate of 30 ml minꢅ1
.
2.3. Refinement
The crystal structure of Cs3(H1.5PO4)2ꢁ2H2O has been
determined from single-crystal X-ray diffraction (SC-XRD).
All heavy atoms were refined anisotropically without
restraints. H-atom coordinates were refined, with Uiso(H) =
1.2Ueq(O). The H2 atom is involved in a strong O—Hꢁ ꢁ ꢁO
hydrogen bond and was refined freely; its central position
suggested the symmetric nature of the hydrogen bond. We
selected this model with the H atom lying at a symmetry
centre instead of that with the H atom statistically disordered
between general positions since it gives 0.5–1% lower R factor
values and the only peak in the difference electron-density
map is midway between the donor and acceptor O2 atoms. A
˚
distance restraint of 0.82 (2) A was used for the O3—H3 bond
in a phosphate anion. Data collection and refinement para-
meters, as well as crystal data, for Cs3(H1.5PO4)2ꢁ2H2O are
summarized in Table 1. Indexing and refinement of the lattice
Figure 2
PXRD pattern of Cs3(H1.5PO4)2ꢁ2H2O. The black solid line with circles is
the observed pattern, the red solid line is the calculated pattern and the
vertical markers are the positions of the Bragg reflections for
Cs3(H1.5PO4)2ꢁ2H2O.
Figure 3
(a) The cb and (b) the ab projection of the Cs3(H1.5PO4)2ꢁ2H2O crystal
structure.
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tance of the samples. The measurements were carried out on
heating and on cooling, with a rate of ꢃ0.5–1.0 K minꢅ1, as
well as during long-term storage at 513 K for at least 1–2 h in
air with ꢃ10–15% relative humidity (RH). In the latter case,
the steady-state values of the conductivity were reached.
The hydrogen phosphate species have typical tetrahedral
˚
geometry, with an average P—O distance of 1.534 A, which
agrees with the length expected for a P—O bond. All four O
atoms participate in hydrogen-bond formation. The P—O1
˚
distance is 1.513 (4) A and atom O1 forms two medium-
strength hydrogen bonds with two hydrate water molecules.
The P—O2 distance corresponds to the oxygen apex of the
[PO4] tetrahedron that is involved in the strong symmetric
hydrogen bond, i.e. O2—H2ꢁ ꢁ ꢁO2i (see Table 2 for hydrogen-
bond details and symmetry codes). The shortest [P—O4 =
3. Results and discussion
Fig. 2 presents the PXRD pattern of the synthesized Cs3-
(H1.5PO4)2ꢁ2H2O compound. A single-crystal diffraction
analysis showed that this compound crystallizes in the ortho-
rhombic space group Pbca. A fragment of the crystal structure
is shown schematically in Fig. 3. The asymmetric unit contains
two Cs atoms. Cs1 is twleve-coordinated to O atoms, with
˚
˚
1.498 (4) A] and longest [P—O3 = 1.590 (4) A] distances
˚
Cs—O distances ranging from 3.146 (4) to 3.712 (5) A, and the
coordination sphere of Cs2 is defined by eight O atoms, with
˚
Cs—O distances ranging from 3.130 (5) to 3.479 (4) A. The
coordination environments of the Cs1 and Cs2 atoms are
˚
located at mean distances of 3.380 and 3.258 A, respectively,
˚
which agree with the mean radius of 1.88 A for twelve-
+
coordinated and 1.74 A for eight-coordinated Cs ions
˚
˚
(Shannon, 1976), assuming an oxygen-anion radius of 1.40 A.
The two symmetry-independent Cs+ cations are located in the
layers parallel to (001) or in the voids in the [PO3(OH)]ꢅ
layers.
Unlike in the known mixed divalent cation phosphates
MBa2(HPO4)2(H2PO4)2 (M = Ca, Cd, Mn) (Ben Tahar et al.,
1999; Taher et al., 2001; Sun et al., 2012), only one type of
phosphate tetrahedron was observed in Cs3(H1.5PO4)2ꢁ2H2O.
Figure 4
Figure 5
Schematic representation of the network of hydrogen bonds in an ac
projection of the Cs3(H1.5PO4)2ꢁ2H2O structure. Hydrogen bonds are
shown as dashed lines.
The IR spectra of Cs3(H1.5PO4)2ꢁ2H2O, 1, and Cs2HPO4ꢁ2H2O, 2, showing
(a) the region of hydrogen bonds and (b) the region of phosphate
tetrahedra.
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Bratos, 1976). Three bands (ꢃ2790, 2350 and 1745 cmꢅ1) are
observed in the O—H stretching and bending region of the IR
spectrum, confirming the presence of strong hydrogen bonds.
These spectral characteristics have been observed in a variety
of strong hydrogen-bonded solids having Oꢁ ꢁ ꢁO distances
Table 2
Hydrogen-bond geometry (A, ).
ꢂ
˚
D—Hꢁ ꢁ ꢁA
D—H
Hꢁ ꢁ ꢁA
Dꢁ ꢁ ꢁA
D—Hꢁ ꢁ ꢁA
O2—H2ꢁ ꢁ ꢁO2i
O3—H3ꢁ ꢁ ꢁO4ii
O5—H5Aꢁ ꢁ ꢁO1iii
O5—H5Bꢁ ꢁ ꢁO1iv
1.22 (1)
0.80 (2)
0.82 (8)
0.90 (8)
1.22 (1)
1.75 (2)
1.90 (8)
1.82 (8)
2.445 (7)
2.549 (5)
2.713 (6)
2.725 (6)
180 (1)
177 (6)
175 (7)
176 (7)
˚
varying from 2.4 to 2.6 A (Taher et al., 2001; Sun et al., 2012;
Marchon & Novak, 1983; Baran et al., 1989). The band with a
maximum lying at 2350 cmꢅ1 and a shoulder around
2200 cmꢅ1 may be related to the presence of two different
types of hydrogen bonds with different lengths. The broad
band at ꢃ750 cmꢅ1 is characterized by out-of-plane-bending
vibrations, in accordance with the literature (Marchon &
Novak, 1983; Baran et al., 1989).
1
2
1
2
Symmetry codes: (i) ꢅx þ 2; ꢅy; ꢅz; (ii) x ꢅ ; ꢅy þ ; ꢅz; (iii) x ꢅ 1; y; z; (iv)
1
2
1
2
x ꢅ ; y; ꢅz þ .
correspond to the formation of an O3—H3ꢁ ꢁ ꢁO4ii hydrogen
bond. The symmetry of the [PO4] groups is close to tetra-
hedral, as is evidenced by small (less than 5ꢂ) deviations of the
O—P—O angles from the value of 109.28ꢂ for an ideal
tetrahedron. The crystal structure is formed by tetrahedra
connected via strong O2—H2ꢁ ꢁ ꢁO2i and O3—H3ꢁ ꢁ ꢁO4ii
hydrogen bonds, forming undulating sheets parallel to (001)
(Fig. 3). Adjacent sheets are bound to each other via medium-
strength hydrogen bonds involving two symmetrically-
equivalent water molecules, forming a three-dimensional
network. The overall hydrogen-bonding scheme in Cs3-
(H1.5PO4)2ꢁ2H2O is illustrated in Fig. 4. The IR spectra (Fig. 5)
agree with the existence of a network of strong hydrogen
bonds. The broad band at ꢃ3145 cmꢅ1 is associated with the
stretching vibrations of the crystal water molecules involved in
the hydrogen-bond network. The ABC-type broad bands of
high-frequency H-atom vibrations have been interpreted as
O—H stretching modes in Fermi resonance with a combina-
tion involving mainly the O—H bending vibrations (Hadzi &
The differential scanning calorimetry (DSC) and thermo-
gravimetry (TGA) data are shown in Fig. 6. TGA and DSC
curves for Cs2HPO4ꢁ2H2O are also shown for comparison.
According to the TGA, Cs3(H1.5PO4)2ꢁ2H2O is stable up to
343 K; only a slight weight loss (less than ꢃ0.15%) occurs until
343 K, which is related to the removal of adsorbed water from
the surface of the hygroscopic compound when stored in air.
Three endothermic effects are observed on dehydration of
Cs3(H1.5PO4)2ꢁ2H2O and its further thermal decomposition.
The first effect, with an onset temperature of ꢃ318 K, is
associated with the removal of crystalline water and agrees
with the theoretical weight loss of 5.73%. Anhydrous
Cs3(H1.5PO4)2 is stable up to 548 K. Its thermal decomposi-
tion, with the formation Cs4P2O7 and CsPO3, occurs in two
stages. The first stage is observed at 548–598 K and the second
in the temperature range 613–673 K, with a total weight loss of
4.56%. The observed total weight loss of the sample heated to
703 K is 10.2%, which agrees well with the theoretical value
for Cs3(H1.5PO4)2ꢁ2H2O (10.29%). Comparing the DSC and
TGA data for the two crystal hydrates, i.e. Cs3(H1.5PO4)2ꢁ-
2H2O and Cs2HPO4ꢁ2H2O, one can see that the dehydration
proceeds in one and two stages, respectively, in accordance
with the nonequivalence of Cs2HPO4ꢁ2H2O crystal water
molecules. The region of thermal stability of the dehydrated
Figure 6
Figure 7
PXRD pattern of Cs3(H1.5PO4)2 at 433 K. Vertical lines represent the
positions of the Bragg reflections in a monoclinic C2 cell.
DSC and TGA curves for the powders of Cs3(H1.5PO4)2ꢁ2H2O, 1, and
Cs2HPO4ꢁ2H2O, 2.
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compounds differs markedly and is 383 K narrower for the
Cs3(H1.5PO4)2 salt.
ꢃ0.91 eV. The processes defining the temperature dependence
of conductivity are consistent with the DSC and TGA data.
The proton conductivity of Cs3(H1.5PO4)2 is comparable with
that of the low-temperature (P21/m) phase of CsH2PO4
(Baranov et al., 1988; Preisinger et al., 1994; Ueso &
Kobayashi, 1976; Matsunaga et al., 1980) and of Cs2HPO4
The space group and unit-cell parameters of anhydrous
Cs3(H1.5PO4)2 at 433 K were also defined. TOPAS (Coelho et
al., 2011) was used to index the diffraction pattern and
refine the unit-cell parameters. The PXRD pattern of
Cs3(H1.5PO4)2 (Fig. 7) was indexed as a monoclinic C2 cell,
¨
(putative structure in the C2/c group) (Stoger & Weil, 2014;
˚
˚
with unit-cell parameters a = 11.1693 (4) A, b = 6.4682 (2) A,
ꢂ
Ponomareva et al., 2017). In these phases, the activation
energy of conductivity is determined by the energy of the
formation of proton defects and by their mobility according to
the de Grotthuss mechanism (de Grotthuss, 1806; Kreuer,
1997a). A similar mechanism of proton transfer is likely for
Cs3(H1.5PO4)2.
˚
c = 7.7442 (3) A and ꢀ = 71.822 (2) .
The temperature dependence of the proton conductivity
agrees with the structural and thermodynamic characteristics
(Fig. 8). The dehydration of Cs3(H1.5PO4)2ꢁ2H2O starts above
348 K and is accompanied by crystal fragmentation; therefore,
the conductivity was measured for polycrystalline samples.
The conductivity of the initial Cs3(H1.5PO4)2ꢁ2H2O at room
temperature is ꢃ6 ꢄ 10ꢅ5 S cmꢅ1 (RH ꢃ10%). This rather
high conductivity value is related to the presence of crystal
water molecules in the structure. The proton conductivity
values at low temperatures depended significantly on the RH.
This is common for crystal hydrates (Colomban, 1992; Kreuer,
1997b). At T > 348 K, the conductivity increased sharply,
reaching ꢃ8 ꢄ 10ꢅ3–10ꢅ2 S cmꢅ1. This increase is related to
the dehydration of the weakly bound water molecules, which
are trapped in the bulk of the sample down to ꢃ453 K,
providing conductive channels and accounting for the high
proton conductivity. The removal of the crystal water from the
dense Cs3(H1.5PO4)2ꢁ2H2O samples is slow, and this leads to
values of the conductivity as high as 10ꢅ2 S cmꢅ1 when heating
the samples at 373–453 K. A further increase in temperature
and long-term storage at 493 K results in a conductivity
decrease of more than three orders of magnitude, as the
dehydration is completed. The conductivity of anhydrous
Cs3(H1.5PO4)2 is characterized by linear Arrhenius depen-
dence, with the low and reproducible values in subsequent
4. Conclusion
A new compound, Cs3(H1.5PO4)2ꢁ2H2O, has been synthesized
and its crystal structure has been determined for the first time.
Cs3(H1.5PO4)2ꢁ2H2O crystallizes in the Pbca space group and
is characterized by a three-dimensional hydrogen-bond
network that consists of undulating sheets of tetrahedra
connected via medium-strength hydrogen bonds involving two
symmetrically equivalent water molecules. Phosphate tetra-
hedra in the sheets were shown to be bonded by strong
˚
hydrogen bonds with lengths of 2.445 (7) and 2.549 (5) A. Two
symmetrically independent twelve- and eight-coordinated Cs+
cations are located in layers parallel to (001) or in the voids in
[PO3(OH)]ꢅ layers. The hydrogen bonds in the crystal struc-
ture are strong and ordered, which was confirmed by IR
spectroscopic analysis. The anhydrous Cs3(H1.5PO4)2 phase
was determined to belong to the monoclinic C2 space group.
The proton conductivities of the new compound, Cs3-
(H1.5PO4)2ꢁ2H2O, and of its dehydrated form are related to
their crystal structures. The proton conductivity of Cs3-
(H1.5PO4)2ꢁ2H2O is 10ꢅ5 S cmꢅ1 at T = 303 K. On heating, as
dehydration starts, the proton conductivity first increases
sharply, reaching a value of ꢃ8 ꢄ 10ꢅ3–10ꢅ2 S cmꢅ1, as water
is trapped in the sample, but then decreases to 6 ꢄ 10ꢅ6–10ꢅ8 S
cmꢅ1 at 373–493 K; dehydration to the anhydrous
Cs3(H1.5PO4)2 phase is complete at T > 433 K.
heating–cooling cycles at 373–493 K (Fig. 8) being ꢃ6 ꢄ 10ꢅ6
–
10ꢅ8 S cmꢅ1 and the activation energy of conductivity being
Acknowledgements
The authors thank K. B. Gerasimov [Institute of Solid State
Chemistry and Mechanochemistry SB RAS (ISSCM SB
RAS)] for experiments on thermal properties and A. A.
Matvienko for EDS measurements (ISSCM SB RAS).
Funding information
Funding for this research was provided by: Integration
Program of the Siberian Branch of RAS II.2P ‘Integration and
Development’ (award No. II.2P/V.47-2).
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Figure 8
The temperature dependencies of conductivity for Cs3(H1.5PO4)2ꢁyH2O
(heating mode) and Cs3(H1.5PO4)2 (cooling mode).
ꢀ
6 of 7 Ponomareva et al. Proton conductivity of Cs3(H2PO4)(HPO4)ꢁ2H2O
Acta Cryst. (2017). C73

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Acta Cryst. (2017). C73
Ponomareva et al.
Proton conductivity of Cs3(H2PO4)(HPO4)ꢁ2H2O 7 of 7

supporting information
supporting information
Acta Cryst. (2017). C73 [https://doi.org/10.1107/S2053229617012335]
Crystal structure and proton conductivity of a new Cs3(H2PO4)(HPO4)·2H2O
phase in the caesium di- and monohydrogen orthophosphate system
Valentina Ponomareva, Irina Bagryantseva, Boris Zakharov, Natalia Bulina, Galina Lavrova and
Elena Boldyreva
Computing details
Data collection: CrysAlis PRO (Rigaku OD, 2016); cell refinement: CrysAlis PRO (Rigaku OD, 2016); data reduction:
CrysAlis PRO (Rigaku OD, 2016); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to
refine structure: SHELXL2016 (Sheldrick, 2015) and ShelXle (Hübschle et al., 2011); molecular graphics: DIAMOND
(Brandenburg & Putz, 1999); software used to prepare material for publication: SHELXL2016 (Sheldrick, 2015).
(I)
Crystal data
Cs3(H2PO4)(HPO4)·2H2O
Mr = 627.73
Dx = 3.285 Mg m−3
Mo Kα radiation, λ = 0.71073 Å
Cell parameters from 9404 reflections
θ = 2.7–29.2°
µ = 8.85 mm−1
T = 296 K
Block, colourless
Orthorhombic, Pbca
a = 7.4721 (5) Å
b = 11.4369 (8) Å
c = 14.8509 (11) Å
V = 1269.12 (15) Å3
Z = 4
0.20 × 0.05 × 0.02 mm
F(000) = 1128
Data collection
Agilent Xcalibur Ruby Gemini ultra
diffractometer
Radiation source: sealed X-ray tube
Detector resolution: 10.3457 pixels mm-1
ω scan
17880 measured reflections
1298 independent reflections
1176 reflections with I > 2σ(I)
Rint = 0.086
θ
max = 26.4°, θmin = 3.5°
Absorption correction: multi-scan
(CrysAlis PRO; Rigaku OD, 2016)
h = −9→9
k = −14→14
l = −18→18
T
min = 0.453, Tmax = 1.000
Refinement
Refinement on F2
Least-squares matrix: full
R[F2 > 2σ(F2)] = 0.030
wR(F2) = 0.074
S = 1.05
1298 reflections
79 parameters
1 restraint
Primary atom site location: structure-invariant
direct methods
Secondary atom site location: difference Fourier
map
Hydrogen site location: difference Fourier map
Only H-atom coordinates refined
w = 1/[σ2(Fo2) + (0.0383P)2 + 3.3232P]
where P = (Fo2 + 2Fc2)/3
Acta Cryst. (2017). C73
sup-1

supporting information
(Δ/σ)max = 0.001
Δρmax = 0.85 e Å−3
Δρmin = −1.14 e Å−3
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)
x
y
z
Uiso*/Ueq
Cs1
Cs2
P1
O1
O2
H2
O3
H3
0.07728 (4)
0.000000
0.99034 (15)
1.0725 (5)
0.9101 (5)
1.000000
0.82817 (3)
0.500000
0.17285 (10)
0.1525 (4)
0.0612 (3)
0.000000
0.2562 (3)
0.262 (5)
0.17311 (2)
0.000000
0.09057 (8)
0.1823 (3)
0.0501 (3)
0.000000
0.1086 (2)
0.066 (3)
0.02937 (14)
0.03806 (17)
0.0220 (3)
0.0364 (10)
0.0389 (9)
0.047*
0.8240 (5)
0.759 (7)
0.0337 (8)
0.040*
O4
O5
H5A
H5B
1.1154 (5)
0.3745 (7)
0.282 (10)
0.445 (9)
0.2333 (4)
0.0228 (4)
0.061 (6)
0.0270 (3)
0.2003 (3)
0.198 (5)
0.0426 (9)
0.0423 (10)
0.051*
0.066 (6)
0.237 (5)
0.051*
Atomic displacement parameters (Å2)
U11
U22
U33
U12
U13
U23
Cs1
Cs2
P1
O1
O2
O3
O4
O5
0.0299 (2)
0.0458 (3)
0.0209 (6)
0.028 (2)
0.037 (2)
0.0289 (19)
0.049 (2)
0.046 (2)
0.0290 (2)
0.0320 (3)
0.0258 (6)
0.051 (2)
0.0306 (19)
0.042 (2)
0.046 (2)
0.032 (2)
0.0292 (2)
−0.00062 (11)
0.00700 (19)
−0.0006 (4)
0.0072 (16)
−0.0061 (15)
0.0121 (15)
−0.0098 (19)
0.0103 (19)
0.00038 (12)
−0.0036 (2)
0.0015 (4)
−0.0026 (14)
0.0049 (17)
−0.0054 (15)
0.0127 (18)
−0.017 (2)
0.00102 (11)
0.00316 (18)
−0.0018 (5)
0.0015 (17)
−0.0183 (17)
−0.0126 (16)
−0.0004 (18)
−0.0093 (19)
0.0363 (3)
0.0194 (6)
0.030 (2)
0.049 (2)
0.030 (2)
0.033 (2)
0.049 (3)
Geometric parameters (Å, º)
Cs1—O1i
Cs1—O5ii
Cs1—O3iii
Cs1—O5iv
Cs1—O1v
Cs1—O4v
Cs1—O4vi
Cs1—O3i
Cs1—O2vii
Cs1—O5iii
3.146 (4)
Cs2—O5viii
Cs2—O4vi
Cs2—O4ix
Cs2—O2iii
Cs2—O2viii
Cs2—O3vi
Cs2—O3ix
Cs2—P1vi
Cs2—P1ix
P1—O4
3.130 (5)
3.170 (5)
3.253 (4)
3.284 (4)
3.302 (4)
3.341 (4)
3.376 (4)
3.424 (4)
3.465 (4)
3.534 (4)
3.194 (4)
3.194 (4)
3.230 (4)
3.230 (4)
3.479 (4)
3.479 (4)
3.9767 (12)
3.9767 (12)
1.498 (4)
Acta Cryst. (2017). C73
sup-2

supporting information
Cs1—O2vi
Cs1—O1vii
Cs2—O5iii
3.549 (4)
3.712 (5)
3.130 (5)
P1—O1
P1—O2
P1—O3
1.513 (4)
1.533 (4)
1.590 (4)
O1i—Cs1—O5ii
O1i—Cs1—O3iii
O5ii—Cs1—O3iii
O1i—Cs1—O5iv
O5ii—Cs1—O5iv
O3iii—Cs1—O5iv
O1i—Cs1—O1v
O5ii—Cs1—O1v
O3iii—Cs1—O1v
O5iv—Cs1—O1v
O1i—Cs1—O4v
O5ii—Cs1—O4v
O3iii—Cs1—O4v
O5iv—Cs1—O4v
O1v—Cs1—O4v
O1i—Cs1—O4vi
O5ii—Cs1—O4vi
O3iii—Cs1—O4vi
O5iv—Cs1—O4vi
O1v—Cs1—O4vi
O4v—Cs1—O4vi
O1i—Cs1—O3i
O5ii—Cs1—O3i
O3iii—Cs1—O3i
O5iv—Cs1—O3i
O1v—Cs1—O3i
O4v—Cs1—O3i
O4vi—Cs1—O3i
O1i—Cs1—O2vii
O5ii—Cs1—O2vii
O3iii—Cs1—O2vii
O5iv—Cs1—O2vii
O1v—Cs1—O2vii
O4v—Cs1—O2vii
O4vi—Cs1—O2vii
O3i—Cs1—O2vii
O1i—Cs1—O5iii
O5ii—Cs1—O5iii
O3iii—Cs1—O5iii
O5iv—Cs1—O5iii
O1v—Cs1—O5iii
O4v—Cs1—O5iii
O4vi—Cs1—O5iii
O3i—Cs1—O5iii
127.65 (11)
73.22 (10)
149.39 (10)
83.00 (11)
76.96 (9)
85.11 (11)
82.24 (11)
82.35 (10)
126.06 (10)
138.97 (11)
118.72 (10)
80.16 (11)
111.11 (9)
155.38 (11)
44.33 (9)
O2viii—Cs2—P1vi
O3vi—Cs2—P1vi
O3ix—Cs2—P1vi
O5iii—Cs2—P1ix
O5viii—Cs2—P1ix
O4vi—Cs2—P1ix
O4ix—Cs2—P1ix
O2iii—Cs2—P1ix
O2viii—Cs2—P1ix
O3vi—Cs2—P1ix
O3ix—Cs2—P1ix
P1vi—Cs2—P1ix
O5iii—Cs2—Cs1x
O5viii—Cs2—Cs1x
O4vi—Cs2—Cs1x
O4ix—Cs2—Cs1x
O2iii—Cs2—Cs1x
O2viii—Cs2—Cs1x
O3vi—Cs2—Cs1x
O3ix—Cs2—Cs1x
P1vi—Cs2—Cs1x
P1ix—Cs2—Cs1x
O5iii—Cs2—Cs1xi
O5viii—Cs2—Cs1xi
O4vi—Cs2—Cs1xi
O4ix—Cs2—Cs1xi
O2iii—Cs2—Cs1xi
O2viii—Cs2—Cs1xi
O3vi—Cs2—Cs1xi
O3ix—Cs2—Cs1xi
P1vi—Cs2—Cs1xi
P1ix—Cs2—Cs1xi
Cs1x—Cs2—Cs1xi
O4—P1—O1
96.25 (7)
23.42 (6)
156.58 (6)
76.26 (8)
103.74 (8)
159.35 (7)
20.65 (7)
96.25 (7)
83.75 (7)
156.58 (6)
23.42 (6)
180.00 (4)
135.51 (9)
44.49 (9)
47.57 (8)
132.43 (8)
51.24 (8)
128.76 (8)
69.65 (6)
110.35 (6)
53.948 (17)
126.052 (18)
44.49 (9)
135.51 (9)
132.43 (8)
47.57 (8)
128.76 (8)
51.24 (8)
110.35 (6)
69.65 (6)
126.052 (17)
53.948 (17)
180.0
108.40 (9)
123.86 (11)
45.19 (9)
116.64 (11)
104.34 (10)
69.74 (3)
43.73 (9)
84.10 (10)
114.61 (10)
73.77 (11)
69.13 (9)
112.88 (9)
151.03 (9)
136.30 (9)
77.26 (10)
72.97 (9)
67.31 (10)
140.87 (9)
98.91 (9)
112.7 (2)
112.4 (2)
112.6 (3)
108.5 (2)
104.9 (2)
105.1 (2)
57.93 (16)
56.54 (16)
146.05 (15)
108.83 (14)
57.03 (16)
62.76 (9)
O4—P1—O2
O1—P1—O2
O4—P1—O3
O1—P1—O3
139.62 (9)
47.72 (11)
127.44 (7)
82.97 (11)
130.65 (5)
46.61 (10)
71.53 (10)
86.45 (11)
68.44 (10)
O2—P1—O3
O4—P1—Cs1xii
O1—P1—Cs1xii
O2—P1—Cs1xii
O3—P1—Cs1xii
O4—P1—Cs1vi
Acta Cryst. (2017). C73
sup-3

supporting information
O2vii—Cs1—O5iii
O1i—Cs1—O2vi
O5ii—Cs1—O2vi
O3iii—Cs1—O2vi
O5iv—Cs1—O2vi
O1v—Cs1—O2vi
O4v—Cs1—O2vi
O4vi—Cs1—O2vi
O3i—Cs1—O2vi
O2vii—Cs1—O2vi
O5iii—Cs1—O2vi
O1i—Cs1—O1vii
O5ii—Cs1—O1vii
O3iii—Cs1—O1vii
O5iv—Cs1—O1vii
O1v—Cs1—O1vii
O4v—Cs1—O1vii
O4vi—Cs1—O1vii
O3i—Cs1—O1vii
O2vii—Cs1—O1vii
O5iii—Cs1—O1vii
O2vi—Cs1—O1vii
O5iii—Cs2—O5viii
O5iii—Cs2—O4vi
O5viii—Cs2—O4vi
O5iii—Cs2—O4ix
O5viii—Cs2—O4ix
O4vi—Cs2—O4ix
O5iii—Cs2—O2iii
O5viii—Cs2—O2iii
O4vi—Cs2—O2iii
O4ix—Cs2—O2iii
O5iii—Cs2—O2viii
O5viii—Cs2—O2viii
O4vi—Cs2—O2viii
O4ix—Cs2—O2viii
O2iii—Cs2—O2viii
O5iii—Cs2—O3vi
O5viii—Cs2—O3vi
O4vi—Cs2—O3vi
O4ix—Cs2—O3vi
O2iii—Cs2—O3vi
O2viii—Cs2—O3vi
O5iii—Cs2—O3ix
O5viii—Cs2—O3ix
O4vi—Cs2—O3ix
O4ix—Cs2—O3ix
O2iii—Cs2—O3ix
149.01 (10)
150.96 (9)
81.37 (10)
80.78 (9)
107.78 (10)
103.57 (9)
59.38 (9)
O1—P1—Cs1vi
160.89 (15)
63.79 (17)
93.97 (14)
114.88 (3)
115.50 (16)
47.43 (16)
132.10 (16)
58.82 (13)
67.79 (2)
149.62 (3)
48.76 (16)
116.25 (18)
131.13 (17)
60.45 (15)
70.21 (2)
O2—P1—Cs1vi
O3—P1—Cs1vi
Cs1xii—P1—Cs1vi
O4—P1—Cs1xiii
O1—P1—Cs1xiii
O2—P1—Cs1xiii
O3—P1—Cs1xiii
Cs1xii—P1—Cs1xiii
Cs1vi—P1—Cs1xiii
O4—P1—Cs2xiv
O1—P1—Cs2xiv
O2—P1—Cs2xiv
O3—P1—Cs2xiv
Cs1xii—P1—Cs2xiv
Cs1vi—P1—Cs2xiv
Cs1xiii—P1—Cs2xiv
O4—P1—Cs1xv
O1—P1—Cs1xv
O2—P1—Cs1xv
O3—P1—Cs1xv
Cs1xii—P1—Cs1xv
Cs1vi—P1—Cs1xv
Cs1xiii—P1—Cs1xv
Cs2xiv—P1—Cs1xv
P1—O1—Cs1xiii
P1—O1—Cs1xii
Cs1xiii—O1—Cs1xii
P1—O1—Cs1xv
Cs1xiii—O1—Cs1xv
Cs1xii—O1—Cs1xv
P1—O2—Cs2xvi
P1—O2—Cs1xv
Cs2xvi—O2—Cs1xv
P1—O2—Cs1vi
42.57 (9)
164.55 (8)
40.78 (11)
117.14 (9)
127.56 (6)
45.60 (9)
104.76 (9)
45.34 (10)
127.89 (7)
110.79 (9)
103.69 (9)
101.96 (9)
41.17 (8)
70.71 (2)
83.12 (2)
121.58 (17)
61.79 (17)
52.45 (16)
129.64 (16)
102.09 (3)
107.94 (3)
100.53 (3)
169.71 (3)
111.82 (19)
100.98 (19)
85.50 (11)
97.16 (19)
131.82 (13)
126.80 (10)
129.92 (19)
107.01 (19)
107.25 (10)
93.40 (18)
83.54 (9)
169.82 (10)
71.25 (8)
180.00 (15)
96.92 (11)
83.08 (11)
83.08 (11)
96.92 (11)
180.00 (14)
92.72 (11)
87.28 (11)
64.26 (10)
115.74 (10)
87.28 (11)
92.72 (11)
115.74 (10)
64.26 (10)
180.0
Cs2xvi—O2—Cs1vi
Cs1xv—O2—Cs1vi
P1—O3—Cs1xi
139.22 (11)
157.2 (2)
97.79 (15)
81.91 (8)
96.13 (17)
106.39 (10)
99.49 (9)
105.11 (9)
74.89 (9)
43.86 (9)
136.14 (9)
106.96 (9)
73.04 (9)
P1—O3—Cs1xiii
Cs1xi—O3—Cs1xiii
P1—O3—Cs2xiv
Cs1xi—O3—Cs2xiv
Cs1xiii—O3—Cs2xiv
P1—O4—Cs2xiv
P1—O4—Cs1xii
Cs2xiv—O4—Cs1xii
P1—O4—Cs1vi
74.89 (9)
110.6 (2)
105.11 (9)
136.14 (9)
43.86 (9)
99.74 (19)
87.54 (10)
101.11 (19)
88.48 (10)
73.04 (9)
Cs2xiv—O4—Cs1vi
Acta Cryst. (2017). C73
sup-4

supporting information
O2viii—Cs2—O3ix
O3vi—Cs2—O3ix
O5iii—Cs2—P1vi
O5viii—Cs2—P1vi
O4vi—Cs2—P1vi
O4ix—Cs2—P1vi
O2iii—Cs2—P1vi
106.96 (9)
180.0
Cs1xii—O4—Cs1vi
Cs2xvi—O5—Cs1xvii
Cs2xvi—O5—Cs1xviii
Cs1xvii—O5—Cs1xviii
Cs2xvi—O5—Cs1xi
Cs1xvii—O5—Cs1xi
Cs1xviii—O5—Cs1xi
158.85 (12)
91.74 (11)
110.45 (13)
85.42 (11)
86.75 (11)
138.66 (14)
133.48 (14)
103.74 (8)
76.26 (8)
20.65 (7)
159.35 (7)
83.75 (7)
O4—P1—O1—Cs1xiii
O2—P1—O1—Cs1xiii
O3—P1—O1—Cs1xiii
Cs1xii—P1—O1—Cs1xiii
Cs1vi—P1—O1—Cs1xiii
Cs2xiv—P1—O1—Cs1xiii
Cs1xv—P1—O1—Cs1xiii
O4—P1—O1—Cs1xii
O2—P1—O1—Cs1xii
O3—P1—O1—Cs1xii
Cs1vi—P1—O1—Cs1xii
Cs1xiii—P1—O1—Cs1xii
Cs2xiv—P1—O1—Cs1xii
Cs1xv—P1—O1—Cs1xii
O4—P1—O1—Cs1xv
O2—P1—O1—Cs1xv
O3—P1—O1—Cs1xv
Cs1xii—P1—O1—Cs1xv
Cs1vi—P1—O1—Cs1xv
Cs1xiii—P1—O1—Cs1xv
Cs2xiv—P1—O1—Cs1xv
O4—P1—O2—Cs2xvi
O1—P1—O2—Cs2xvi
O3—P1—O2—Cs2xvi
Cs1xii—P1—O2—Cs2xvi
Cs1vi—P1—O2—Cs2xvi
Cs1xiii—P1—O2—Cs2xvi
Cs2xiv—P1—O2—Cs2xvi
Cs1xv—P1—O2—Cs2xvi
O4—P1—O2—Cs1xv
O1—P1—O2—Cs1xv
O3—P1—O2—Cs1xv
Cs1xii—P1—O2—Cs1xv
Cs1vi—P1—O2—Cs1xv
Cs1xiii—P1—O2—Cs1xv
Cs2xiv—P1—O2—Cs1xv
O4—P1—O2—Cs1vi
O1—P1—O2—Cs1vi
O3—P1—O2—Cs1vi
Cs1xii—P1—O2—Cs1vi
104.4 (2)
−127.1 (2)
−13.4 (2)
89.52 (19)
158.0 (4)
50.6 (2)
−140.7 (2)
14.9 (2)
143.33 (17)
−102.95 (18)
68.5 (6)
−89.52 (19)
−38.89 (16)
129.74 (15)
−114.8 (2)
13.6 (2)
127.31 (17)
−129.74 (15)
−61.3 (6)
140.7 (2)
−168.64 (4)
−115.2 (3)
116.2 (3)
O4—P1—O3—Cs1xi
O1—P1—O3—Cs1xi
O2—P1—O3—Cs1xi
163.2 (5)
−76.1 (5)
42.8 (5)
−135.3 (4)
106.7 (5)
−87.6 (5)
171.9 (5)
−10.6 (6)
−109.2 (2)
11.5 (2)
130.43 (19)
−47.68 (13)
−165.66 (8)
−100.49 (12)
77.06 (16)
−8.7 (2)
112.02 (19)
−129.08 (19)
52.81 (11)
−65.17 (8)
100.49 (12)
177.55 (6)
−105.7 (2)
125.8 (2)
Cs1xii—P1—O3—Cs1xi
Cs1vi—P1—O3—Cs1xi
Cs1xiii—P1—O3—Cs1xi
Cs2xiv—P1—O3—Cs1xi
Cs1xv—P1—O3—Cs1xi
O4—P1—O3—Cs1xiii
O1—P1—O3—Cs1xiii
O2—P1—O3—Cs1xiii
Cs1xii—P1—O3—Cs1xiii
Cs1vi—P1—O3—Cs1xiii
Cs2xiv—P1—O3—Cs1xiii
Cs1xv—P1—O3—Cs1xiii
O4—P1—O3—Cs2xiv
O1—P1—O3—Cs2xiv
O2—P1—O3—Cs2xiv
Cs1xii—P1—O3—Cs2xiv
Cs1vi—P1—O3—Cs2xiv
Cs1xiii—P1—O3—Cs2xiv
Cs1xv—P1—O3—Cs2xiv
O1—P1—O4—Cs2xiv
O2—P1—O4—Cs2xiv
O3—P1—O4—Cs2xiv
Cs1xii—P1—O4—Cs2xiv
Cs1vi—P1—O4—Cs2xiv
Cs1xiii—P1—O4—Cs2xiv
Cs1xv—P1—O4—Cs2xiv
O1—P1—O4—Cs1xii
O2—P1—O4—Cs1xii
O3—P1—O4—Cs1xii
Cs1vi—P1—O4—Cs1xii
Cs1xiii—P1—O4—Cs1xii
Cs2xiv—P1—O4—Cs1xii
Cs1xv—P1—O4—Cs1xii
O1—P1—O4—Cs1vi
O2—P1—O4—Cs1vi
O3—P1—O4—Cs1vi
Cs1xii—P1—O4—Cs1vi
2.6 (3)
179.36 (6)
−84.4 (2)
63.9 (3)
−61.2 (3)
131.3 (3)
113.4 (2)
−15.1 (2)
−128.78 (17)
48.0 (3)
144.24 (16)
−67.4 (2)
167.51 (6)
−30.8 (2)
−159.38 (16)
86.98 (17)
−96.2 (3)
10.0 (2)
−91.03 (17)
92.57 (19)
−53.5 (2)
−175.58 (5)
−14.7 (2)
−143.19 (18)
101.07 (18)
−176.4 (2)
37.52 (18)
91.03 (17)
−84.55 (15)
161.71 (19)
33.2 (2)
−82.53 (19)
176.4 (2)
Acta Cryst. (2017). C73
sup-5

supporting information
Cs1xiii—P1—O2—Cs1vi
Cs2xiv—P1—O2—Cs1vi
Cs1xv—P1—O2—Cs1vi
148.33 (11)
23.27 (19)
−144.24 (16)
Cs1xiii—P1—O4—Cs1vi
Cs2xiv—P1—O4—Cs1vi
Cs1xv—P1—O4—Cs1vi
−146.08 (7)
−92.57 (19)
91.85 (15)
Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) x, y+1, z; (iii) −x+1/2, y+1/2, z; (iv) x−1/2, y+1, −z+1/2; (v) −x+3/2, y+1/2, z; (vi) −x+1, −y+1, −z; (vii) x−1,
y+1, z; (viii) x−1/2, −y+1/2, −z; (ix) x−1, y, z; (x) x−1/2, −y+3/2, −z; (xi) −x+1/2, y−1/2, z; (xii) −x+3/2, y−1/2, z; (xiii) −x+1, y−1/2, −z+1/2; (xiv) x+1, y,
z; (xv) x+1, y−1, z; (xvi) x+1/2, −y+1/2, −z; (xvii) x, y−1, z; (xviii) x+1/2, y−1, −z+1/2.
Hydrogen-bond geometry (Å, º)
D—H···A
D—H
H···A
D···A
D—H···A
O2—H2···O2xix
O3—H3···O4viii
O5—H5A···O1ix
O5—H5B···O1xx
1.22 (1)
0.80 (2)
0.82 (8)
0.90 (8)
1.22 (1)
1.75 (2)
1.90 (8)
1.82 (8)
2.445 (7)
2.549 (5)
2.713 (6)
2.725 (6)
180 (1)
177 (6)
175 (7)
176 (7)
Symmetry codes: (viii) x−1/2, −y+1/2, −z; (ix) x−1, y, z; (xix) −x+2, −y, −z; (xx) x−1/2, y, −z+1/2.
Acta Cryst. (2017). C73
sup-6