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A room-temperature structural model of titanium pyrophos­phate, TiP2O7, has been determined from synchrotron X-ray data. The structure consists of TiO6 octahedra and PO4 tetrahedra sharing corners in a three-dimensional network. The PO4 tetrahedra form P2O7 groups connecting the TiO6 octahedra. The 3 × 3 × 3 superstructure differs substantially from the parent AB2O7 structure. The P-O-P bonding angles of the pyrophosphate group are between 141.21 (12) and 144.51 (13)° for those groups not located on the threefold axis. The individual TiO6 octahedra and PO4 tetrahedra are somewhat distorted.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100018709/br1307sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270100018709/br1307Isup2.hkl
Contains datablock I

Comment top

The parent structure of AB2O7 was originally described by Levi & Peyronel (1935) with AIV = Si, Ti, Zr, Sn or Hf and BV = P. From powder studies a small cubic unit cell in the space group Pa3 and a = 7.80 (1) Å was found for TiP2O7. Further powder studies have expanded the family to include among others, ZrV2O7 (Peyronel, 1942), UP2O7, ThP2O7 (Burdese & Borlera, 1963), AP2O7 (A = Si, Ge, Sn, Pb, Ti, Zr, Hf, Ce, U) (Völlenke et al., 1963), AP2O7 (A = Ge, Zr, U) (Hagmann & Kierkegaard, 1969), HfV2O7 (Baran, 1976), ReP2O7 (Banks & Sacks, 1982), MoP2O7 (Kinomura et al., 1985) and NbP2O7 (Fukuoka et al., 1995). These materials have recently attained a renewed interest because of their small thermal expansion, Korthuis et al. (1995) found that ZrV2O7 and the mixed phase of ZrV2 - xPxO7, with x up to 0.3, have negative expansion coefficient above 375 K. The materials could also be of use in HPLC as a biocompatible packing material as suggested by Inoue & Ohtaki (1993). \sch

Evidence of a possible 3 × 3 × 3 superstructure at room temperature was first proposed by Völlenke et al. (1963) after careful examination of powder diffraction data for GeP2O7. The small AB2O7 parent structure had in most cases an unrealistic short B—O—B bridging bond distance in the B2O7-group, built by two connected BO4-tetrahedra. In the smaller parent structure, all B2O7-groups are forced to a 180° B—O—B bonding angle since they are located on a threefold axis. The expansions to a 3 × 3 × 3 superstructure removes 96 of the 108 B2O7-groups in the unit cell from the threefold axis, allowing them to adopt B—O—B angles less then 180°. The ability to bend the B—O—B angle increases the bond distances for the B—O bonds connecting the BO4-tetrahedra. For most AB2O7 materials, a phase transition occurs at elevated temperatures from the superstructure to the small cubic structure. ZrV2O7 has, for example, two phase transitions, first to an incommensurate phase at 350 K (Withers et al., 1998), and then to the AB2O7 parent structure at 375 K (Korthuis et al., 1995).

Most of the structural studies of the superstructure have been based on powder diffraction data. So far, only two single-crystal investigations of the superstructures have been published. The SiP2O7 superstructure suggested by Tillmanns et al. (1973) was limited by low resolution and therefore restricted to an isotropic model. Evans et al. (1998) studied the ZrV2O7 structure using synchrotron X-rays resulting in a model closely related to the parent AB2O7 structure. High resolution neutron powder studies of ZrP2O7 by Khosrovani et al. (1996) gave P—O—P angles in the range of 134–162° that are far from the 180° of the parent structure. This structural model also contains a wide range of P—O bond distances, in the range 1.44 (1)–1.66 (1) Å. Recent X-ray powder studies combined with NMR data of TiP2O7 by Sanz et al. (1997) and further NMR studies by Helluy et al. (2000) shows a distorted structure that is less correlated to the smaller substructure. The model obtained in the powder study by Sanz et al. (1997) was geometrically constrained and only six isotropic displacement parameters were refined for the 50 atoms.

Small, high quality crystals of TiP2O7 were prepared in our search for new modifications and isomorphic materials in the KTP family of compounds (KTP = potassium titanyl phosphate, KTiOPO4; Tordjman et al., 1974) to improve the crystal growth and decrease the ionic conductivity. Our preparation method differs from the usual way of obtaining powder/crystals of TiP2O7, which is by reaction of TiO2 and H3PO4 in an autoclave at temperatures around 500 K forming the hydrated phosphate α-Ti(HPO4)2·H2O. Further calcination at temperatures around 900 K results in the formation of TiP2O7 (Soria et al., 1993). The good quality of our crystals, prepared by the method described below, prompted us to collect TiP2O7 single-crystal data at the MAX II synchrotron radiation facility at Lund University, Sweden.

The TiP2O7 structure is built up by TiO6-octahedra and PO4-tetrahedra. The TiO6-octahedra are connected by pyrophosphate groups in a three-dimensional network. Fig. 1 shows the refined TiP2O7 room-temperature superstructure together with the smaller parent structure of AB2O7 in the (001) plane. The selected distances and angles are listed in Table 1.

The highest intensity of a superlattice reflection for ZrV2O7 (Evans et al., 1998) were about 1% of the strongest sublattice reflection, while our data collected for TiP2O7 shows much stronger superlattice reflections. Table 2 gives hkl statistics for the TiP2O7 data generated by SAINT+ (Bruker, 1999). The mean I/σ(I) is 114.96 for the sublattice and 41.95 for the superlattice, so a rather high proportion of the superlattice reflections has intensities comparable to the sublattice reflections. The highest intensity of a superlattice reflection is approximately 30% of the strongest sublattice reflection.

The TiP2O7 superstructure differs considerably from the parent AB2O7 structure as indicated by the high intensity of the superlattice reflection (h,k,l ≠ 3n), while the ZrV2O7 superstructure (Evans et al., 1998) is closely related to the parent AB2O7 substructure. The TiO6-octahedra and PO4-tetrahedra in TiP2O7 are slightly more distorted then the ZrO6-octahedra and VO4-tetrahedra in ZrV2O7. The largest difference between the TiP2O7 and ZrV2O7 superstructure are the B—O—B bridging angles of the B2O7-groups located outside a threefold axis. All Ti—O bonds are in the range 1.8884 (16)–1.9453 (16) Å with a mean bonding distance of 1.915 (14) Å. The O—Ti—O angles are between 86.75 (7) and 92.81 (8)°, while the P—O bonds in the Ti—O—P chain are in the range 1.4893 (18)–1.5069 (17) Å with a mean bonding distance of 1.500 (5) Å. The PO4 tetrahedra bond angles are between 104.16 (10) and 113.61 (10)°.

There are six independent P2O7-groups in the unit cell, two of them are constrained to a 180° P—O—P bridging angle, while the other four have P—O—P angles of 141.21 (12)–144.51 (13)° between the PO4-tetrahedra. This is in good agreement with the combined X-ray powder diffraction/NMR study on TiP2O7 by (Sanz et al., 1997), who reported bridging P—O—P angles in the range 139–145°. The mean P—O bond in the bridging P—O—P is for the four unconstrained pyrophosphate groups 1.575 (5) Å compered to 1.536 (4) Å for the constrained ones. The oxygen atoms O5 and O6 bridging PO4-tetrahedra in the two pyrophosphate group located at a threefold axis show enlarged displacement parameters compared to all other oxygen atoms, as can be seen in Fig. 2, indicating the structural disorder previously suggested by Sanz et al. (1997). The P9—O5—P10 pyrophosphate group seems to have a unlimited numbers of possible bond configurations as shown by the shape of the displacement parameter, while P11—O6—P11 has two possible bond configurations as can be seen in the displacement plot in Fig. 2. The ZrV2O7 (Evans et al., 1998) superstructure does not show any enlarged displacement parameters for the oxygen atoms at a threefold axis and has V—O—V angles in the range 159.3 (2)–167.6 (2)°.

Related literature top

For related literature, see: Banks & Sacks (1982); Baran (1976); Bruker (1999); Burdese & Borlera (1963); Cerenius et al. (2000); Evans et al. (1998); Fukuoka et al. (1995); Hagmann & Kierkegaard (1969); Hall et al. (2000); Helluy et al. (2000); Inoue & Ohtaki (1993); Khosrovani et al. (1996); Kinomura et al. (1985); Korthuis et al. (1995); Levi & Peyronel (1935); Peyronel (1942); Sanz et al. (1997); Sasaki (1989, 1990); Sheldrick (1997); Soria et al. (1993); Tillmanns et al. (1973); Tordjman et al. (1974); Völlenke et al. (1963); Withers et al. (1998); Zachariasen (1967).

Experimental top

The crystals were obtained by spontaneous crystallization from a flux, in a platinum crucible, containing Zn3(PO4)2, P2O5, ZnO and TiO2 carefully mixed together in the molar ratios 1.00:1.55:0.55:1.10. The flux were first dehydrated at 523 K for 15 h and then heated to 1373 K, after which the temperature was decreased to 1073 K by 2.3 K/h. The flux was dissolved in 6 M HCl and the result was a crystalline powder with a weak orange colour. EDX analysis (Electro-scan S4–8DV equipped with a Link eX1 EDX system) indicates no zinc on any of the small, well developed crystals faces.

Refinement top

The X-ray beam at the MAX II beamline 711 (Cerenius et al., 2000) was focused, vertically by a bendable quartz mirror coated with Pt, and horizontally by an asymmetrically cut Si(111) monochromator (an asymmetric angle of 7° is used). A 100 µm collimator with an inherent ionization chamber/counting device and the program SAINT+ (Bruker, 1999) was used to adjust for the intensity changes during the data collection. The different series of frames are later normalized with SADABS (part of the SAINT+ package). The X-ray wavelength was calibrated against Si-powder. A total of eight series of frames were collected over 11 h, with a nominal measuring time of 2 sec per frame. The systematic absences (0kl, k = 2n + 1 and 00 l, l = 2n+1) suggested the space group Pa3 (# 205). The structure was solved by direct methods in SHELXS97 (Sheldrick, 1997) and further least-squares refinement was carried out with the Xtal3.7 software package (Hall et al., 2000). 200 weak reflections with F<4σ(F), that had no effect on the final structural model except for improving the s.u. of some atoms, were added during the final least-squares refinement. Anomalous scattering factors for neutral atoms for the appropriate wavelength were taken from Sasaki (1989). The linear absorption coefficient µ was calculated using mass attenuation coefficients for neutral atoms at the wavelength 0.8522 Å (Sasaki, 1990). About 0.5% of the reflections were affected by extinction (Zachariasen, 1967) with a maximum correction of y = 0.76 for the 006 reflection (the observed structure factor is Fobs = yFkin, were Fkin is the kinematic value of the structure factor).

Computing details top

Data collection: SMART-NT (Bruker, 1998); cell refinement: SAINT+ (Bruker, 1999); data reduction: SAINT+ (Bruker, 1999), Xtal3.7 (Hall et al., 2000) DIFDAT ADDREF ABSORB SORTRF; program(s) used to refine structure: SHELXS97 (Sheldrick, 1997), Xtal3.7 (Hall et al., 2000) CRYLSQ; molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: Xtal3.7 (Hall et al., 2000) BONDLA ATABLE CIFIO.

Figures top
[Figure 1] Fig. 1. Two polyhedra layers of (a) the TiP2O7 superstructure and (b) the substructure (Levi & Peyronel, 1935) in the (001) plane.
[Figure 2] Fig. 2. ORTEPIII (Burnett & Johnson, 1996) views of different pyrophosphate groups. (a) shows a normal bent P2O7 group while (b) and (c) show two kinds of statistical disorder on the threefold symmetry axis. Displacement ellipsoids are drawn at the 80% probability level. [Symmetry codes: (i) 1 - x, - y, - z; (ii) 1 - z, 1 - x, - y; (iii) z + 1/2, - x + 1/2, - y; (iv) 1 - z, - x, - y; (v) 1 - z, x - 1/2, - y + 1/2; (vi) y + 1/2, - z + 1/2, 1 - x; (vii) z + 1/2, x, -y + 1/2; (viii) x + 1/2, y, - z + 1/2; (ix) y + 1/2, z, - x + 1/2; (x) - z + 1/2, x - 1/2, y; (xi) - y + 1/2, - z, x - 1/2.]
(I) top
Crystal data top
TiP2O7Melting point: not measured K
Mr = 221.82Synchrotron x-ray vertical wiggler radiation, λ = 0.8522 (5) Å
Cubic, Pa3Cell parameters from 7382 reflections
Hall symbol: -P 2ac 2ab 3θ = 3.6–43.5°
a = 23.5340 (5) ŵ = 3.74 mm1
V = 13034.3 (5) Å3T = 293 K
Z = 108Rectangular, colourless
F(000) = 116640.06 × 0.02 × 0.02 mm
Dx = 3.052 Mg m3
Data collection top
Bruker SMART area 1000 CCD
diffractometer
8970 independent reflections
Radiation source: MAX II beamline 7118363 reflections with F > 4σ(F)
Si(111) assymetric crystal monochromatorRint = 0.099
area detector scansθmax = 43.5°, θmin = 1.8°
Absorption correction: multi-scan
SADABS (Bruker, 1998)
h = 3026
Tmin = 0.619, Tmax = 0.928k = 3635
82262 measured reflectionsl = 3420
Refinement top
Refinement on F0 constraints
Least-squares matrix: full w = 1/σ2(F)
R[F2 > 2σ(F2)] = 0.046(Δ/σ)max = 0.002
wR(F2) = 0.059Δρmax = 1.14 e Å3
S = 2.78Δρmin = 1.29 e Å3
8563 reflectionsExtinction correction: Gaussian (Zachariasen, 1967), Eq22 p292 "Cryst. Comp." Munksgaard 1970
408 parametersExtinction coefficient: 2303 (43)
0 restraints
Crystal data top
TiP2O7Z = 108
Mr = 221.82Synchrotron x-ray vertical wiggler radiation, λ = 0.8522 (5) Å
Cubic, Pa3µ = 3.74 mm1
a = 23.5340 (5) ÅT = 293 K
V = 13034.3 (5) Å30.06 × 0.02 × 0.02 mm
Data collection top
Bruker SMART area 1000 CCD
diffractometer
8970 independent reflections
Absorption correction: multi-scan
SADABS (Bruker, 1998)
8363 reflections with F > 4σ(F)
Tmin = 0.619, Tmax = 0.928Rint = 0.099
82262 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.046408 parameters
wR(F2) = 0.0590 restraints
S = 2.78Δρmax = 1.14 e Å3
8563 reflectionsΔρmin = 1.29 e Å3
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Ti10.656509 (16)0.160871 (16)0.169981 (16)0.00674 (16)
Ti20.840233 (16)0.003435 (15)0.178285 (16)0.00642 (16)
Ti30.151885 (16)0.007970 (16)0.164157 (16)0.00642 (16)
Ti40.498987 (15)0.004946 (16)0.163064 (16)0.00632 (17)
Ti50.834060 (15)0.334060 (15)0.165940 (15)0.00629 (11)
Ti61000.00581 (15)
P10.78869 (2)0.12394 (2)0.13763 (2)0.0062 (2)
P20.86374 (2)0.20085 (2)0.20655 (2)0.0063 (2)
P30.62838 (2)0.02533 (2)0.20162 (2)0.0066 (2)
P40.71337 (2)0.03675 (2)0.13010 (2)0.0061 (2)
P50.79039 (2)0.03176 (2)0.03638 (2)0.0064 (2)
P60.87058 (2)0.02133 (2)0.04500 (2)0.0061 (2)
P70.28624 (2)0.02618 (2)0.19636 (2)0.0066 (2)
P80.36998 (2)0.03562 (2)0.12360 (2)0.0064 (2)
P90.12310 (2)0.12310 (2)0.12310 (2)0.00695 (15)
P100.69856 (2)0.19856 (2)0.30144 (2)0.00702 (15)
P110.53761 (2)0.03761 (2)0.03761 (2)0.00635 (16)
O10.81178 (8)0.17684 (7)0.17166 (8)0.0169 (9)
O20.68668 (7)0.00194 (8)0.17786 (8)0.0154 (8)
O30.81727 (7)0.01098 (8)0.02117 (7)0.0124 (8)
O40.31292 (7)0.00797 (8)0.14586 (7)0.0162 (8)
O50.66089 (10)0.16089 (10)0.33911 (10)0.0573 (16)
O60.5000.037 (2)
O70.72509 (7)0.12814 (7)0.14237 (8)0.0140 (8)
O80.87117 (7)0.07744 (7)0.19154 (7)0.0139 (8)
O90.80986 (8)0.07093 (7)0.16541 (7)0.0141 (8)
O100.85824 (8)0.26433 (7)0.20113 (7)0.0138 (8)
O110.68105 (8)0.23322 (7)0.14212 (8)0.0168 (9)
O120.18132 (8)0.08233 (7)0.17883 (8)0.0165 (8)
O130.63414 (7)0.08882 (7)0.20247 (8)0.0140 (8)
O140.58070 (7)0.00588 (7)0.16380 (7)0.0122 (8)
O150.12347 (7)0.00010 (7)0.23995 (7)0.0113 (7)
O160.77582 (7)0.03918 (7)0.14399 (7)0.0113 (7)
O170.86788 (7)0.31319 (7)0.09470 (7)0.0135 (8)
O180.50743 (7)0.07451 (7)0.20365 (8)0.0135 (8)
O190.49292 (7)0.03666 (7)0.23141 (7)0.0101 (7)
O200.90446 (7)0.03269 (7)0.21170 (7)0.0131 (8)
O210.17576 (7)0.01031 (7)0.08536 (7)0.0127 (8)
O220.87816 (7)0.00015 (7)0.10491 (6)0.0096 (7)
O230.91957 (7)0.00688 (7)0.00682 (7)0.0111 (7)
O240.08364 (7)0.04439 (8)0.14278 (8)0.0150 (8)
O250.22335 (7)0.02472 (7)0.18604 (7)0.0137 (8)
O260.58611 (7)0.19490 (8)0.19196 (8)0.0156 (8)
O270.80249 (7)0.00473 (7)0.24998 (7)0.0125 (8)
O280.41758 (7)0.01881 (7)0.16290 (7)0.0103 (7)
O290.48794 (7)0.06470 (7)0.12126 (7)0.0100 (7)
O300.62209 (7)0.14061 (8)0.09873 (7)0.0145 (8)
O310.12114 (8)0.06545 (8)0.14993 (8)0.0184 (9)
O320.69123 (9)0.17878 (9)0.24157 (8)0.0216 (10)
O330.50739 (7)0.04426 (7)0.09319 (7)0.0117 (7)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ti10.00690 (16)0.00628 (16)0.00703 (16)0.00027 (11)0.00021 (10)0.00070 (10)
Ti20.00659 (16)0.00629 (16)0.00638 (16)0.00045 (10)0.00027 (11)0.00023 (10)
Ti30.00605 (16)0.00696 (16)0.00625 (16)0.00054 (11)0.00036 (10)0.00019 (10)
Ti40.00680 (17)0.00659 (16)0.00557 (16)0.00062 (10)0.00006 (10)0.00011 (10)
Ti50.00629 (11)0.00629 (11)0.00629 (11)0.00012 (10)0.00012 (10)0.00012 (10)
Ti60.00581 (15)0.00581 (15)0.00581 (15)0.00071 (14)0.00071 (14)0.00071 (14)
P10.0056 (2)0.0065 (2)0.0066 (2)0.00068 (15)0.00019 (15)0.00043 (15)
P20.0065 (2)0.0057 (2)0.0068 (2)0.00061 (15)0.00077 (15)0.00029 (15)
P30.0061 (2)0.0073 (2)0.0065 (2)0.00030 (15)0.00012 (15)0.00052 (16)
P40.0056 (2)0.0070 (2)0.0057 (2)0.00077 (15)0.00060 (15)0.00073 (15)
P50.0062 (2)0.0078 (2)0.0053 (2)0.00040 (15)0.00021 (15)0.00003 (15)
P60.0057 (2)0.0068 (2)0.0058 (2)0.00011 (15)0.00013 (15)0.00036 (15)
P70.0060 (2)0.0079 (2)0.0060 (2)0.00090 (15)0.00048 (15)0.00061 (15)
P80.0063 (2)0.0074 (2)0.0056 (2)0.00016 (15)0.00005 (15)0.00051 (15)
P90.00695 (15)0.00695 (15)0.00695 (15)0.00039 (16)0.00039 (16)0.00039 (16)
P100.00702 (15)0.00702 (15)0.00702 (15)0.00015 (15)0.00015 (15)0.00015 (15)
P110.00635 (16)0.00635 (16)0.00635 (16)0.0006 (5)0.0006 (5)0.0006 (5)
O10.0126 (8)0.0127 (8)0.0252 (9)0.0005 (6)0.0083 (6)0.0082 (6)
O20.0073 (7)0.0219 (9)0.0168 (8)0.0019 (6)0.0022 (6)0.0094 (6)
O30.0087 (7)0.0205 (8)0.0080 (7)0.0052 (6)0.0009 (5)0.0030 (5)
O40.0085 (8)0.0306 (10)0.0096 (8)0.0070 (6)0.0001 (5)0.0068 (6)
O50.0573 (16)0.0573 (16)0.0573 (16)0.0250 (11)0.0250 (11)0.0250 (11)
O60.037 (2)0.037 (2)0.037 (2)0.030 (4)0.030 (4)0.030 (4)
O70.0059 (7)0.0146 (8)0.0216 (9)0.0001 (5)0.0017 (5)0.0038 (6)
O80.0166 (8)0.0090 (7)0.0160 (8)0.0046 (5)0.0006 (6)0.0024 (5)
O90.0198 (9)0.0088 (7)0.0138 (8)0.0054 (6)0.0008 (6)0.0041 (5)
O100.0176 (8)0.0071 (7)0.0168 (8)0.0011 (5)0.0041 (6)0.0016 (5)
O110.0179 (9)0.0072 (8)0.0252 (9)0.0044 (6)0.0021 (6)0.0025 (6)
O120.0224 (9)0.0094 (8)0.0176 (8)0.0059 (6)0.0023 (6)0.0025 (6)
O130.0176 (8)0.0071 (7)0.0172 (8)0.0008 (5)0.0021 (6)0.0027 (5)
O140.0069 (7)0.0196 (8)0.0101 (7)0.0008 (5)0.0020 (5)0.0006 (5)
O150.0176 (8)0.0108 (7)0.0054 (7)0.0025 (5)0.0011 (5)0.0020 (5)
O160.0063 (7)0.0143 (8)0.0133 (7)0.0007 (5)0.0019 (5)0.0027 (5)
O170.0147 (8)0.0161 (8)0.0097 (7)0.0011 (6)0.0026 (5)0.0059 (5)
O180.0153 (8)0.0098 (7)0.0155 (8)0.0050 (5)0.0042 (6)0.0057 (5)
O190.0134 (7)0.0107 (7)0.0062 (7)0.0009 (5)0.0026 (5)0.0004 (5)
O200.0064 (7)0.0175 (8)0.0153 (8)0.0021 (5)0.0014 (5)0.0033 (6)
O210.0127 (8)0.0187 (8)0.0066 (7)0.0010 (6)0.0040 (5)0.0009 (5)
O220.0106 (7)0.0130 (7)0.0051 (7)0.0014 (5)0.0010 (5)0.0008 (5)
O230.0066 (7)0.0169 (8)0.0099 (7)0.0003 (5)0.0021 (5)0.0008 (5)
O240.0087 (8)0.0195 (9)0.0166 (8)0.0023 (6)0.0020 (5)0.0003 (6)
O250.0061 (7)0.0188 (8)0.0161 (8)0.0015 (5)0.0009 (5)0.0032 (6)
O260.0112 (8)0.0185 (9)0.0172 (8)0.0042 (6)0.0063 (6)0.0017 (6)
O270.0168 (8)0.0126 (8)0.0081 (7)0.0016 (5)0.0037 (5)0.0019 (5)
O280.0082 (7)0.0136 (7)0.0090 (7)0.0015 (5)0.0021 (5)0.0016 (5)
O290.0138 (7)0.0065 (7)0.0097 (7)0.0034 (5)0.0010 (5)0.0006 (5)
O300.0160 (8)0.0196 (8)0.0080 (7)0.0023 (6)0.0025 (6)0.0040 (6)
O310.0214 (9)0.0133 (8)0.0207 (9)0.0090 (6)0.0099 (7)0.0083 (6)
O320.0265 (10)0.0254 (10)0.0128 (9)0.0065 (7)0.0082 (7)0.0101 (7)
O330.0144 (8)0.0127 (8)0.0080 (7)0.0058 (5)0.0055 (5)0.0040 (5)
Geometric parameters (Å, º) top
Ti1—O71.9028 (17)P2—O11.578 (2)
Ti1—O111.9138 (18)P2—O101.5051 (17)
Ti1—O131.9333 (17)P2—O121.4938 (18)
Ti1—O261.9114 (18)P2—O111.4982 (18)
Ti1—O301.9224 (17)P3—O21.5805 (18)
Ti1—O321.919 (2)P3—O131.5003 (17)
Ti2—O81.9135 (17)P3—O141.5037 (17)
Ti2—O201.9042 (17)P3—O15i1.5040 (17)
Ti2—O221.9453 (16)P4—O21.5770 (19)
Ti2—O271.9070 (17)P4—O161.5068 (17)
Ti2—O91.9145 (17)P4—O171.5008 (18)
Ti2—O161.9122 (17)P4—O18ii1.4968 (18)
Ti3—O121.9137 (18)P5—O31.5726 (17)
Ti3—O211.9385 (17)P5—O19ii1.5047 (16)
Ti3—O241.8887 (18)P5—O201.5042 (17)
Ti3—O251.9197 (17)P5—O211.4893 (17)
Ti3—O311.9031 (19)P6—O31.5707 (18)
Ti3—O151.9141 (16)P6—O231.5008 (17)
Ti4—O141.9398 (17)P6—O221.5059 (16)
Ti4—O181.9057 (18)P6—O241.5000 (18)
Ti4—O191.8884 (16)P7—O41.5662 (19)
Ti4—O281.9434 (16)P7—O251.5004 (17)
Ti4—O291.9293 (16)P7—O271.5067 (17)
Ti4—O331.8972 (17)P7—O261.5013 (18)
Ti5—O101.9243 (17)P8—O41.5815 (18)
Ti5—O101.9243 (17)P8—O281.5056 (17)
Ti5—O101.9243 (17)P8—O301.5064 (17)
Ti5—O171.9199 (17)P8—O291.5069 (17)
Ti5—O171.9199 (17)P9—O51.541 (2)
Ti5—O171.9199 (17)P9—O311.4970 (19)
Ti6—O231.9065 (16)P9—O31iii1.4970 (19)
Ti6—O231.9065 (16)P9—O31iv1.4970 (19)
Ti6—O231.9065 (16)P10—O51.536 (2)
Ti6—O231.9065 (16)P10—O321.494 (2)
Ti6—O231.9065 (16)P10v—O321.494 (2)
Ti6—O231.9065 (16)P10v—O321.494 (2)
P1—O11.5770 (19)P11—O61.5332 (5)
P1—O71.5041 (17)P11—O331.4972 (17)
P1—O81.4952 (18)P11—O331.4972 (17)
P1—O91.4940 (18)P11—O33ii1.4972 (17)
O7—Ti1—O1189.27 (8)O8—P1—O9112.02 (10)
O7—Ti1—O1390.62 (8)O1—P2—O10104.16 (10)
O7—Ti1—O26175.73 (8)O1—P2—O12109.11 (10)
O7—Ti1—O3087.66 (8)O1—P2—O11108.04 (10)
O7—Ti1—O3291.58 (8)O10—P2—O12112.56 (10)
O11—Ti1—O13176.46 (8)O10—P2—O11112.40 (10)
O11—Ti1—O2688.94 (8)O12—P2—O11110.26 (11)
O11—Ti1—O3092.81 (8)O2—P3—O13105.85 (10)
O11—Ti1—O3288.68 (8)O2—P3—O14109.41 (10)
O13—Ti1—O2691.40 (8)O2—P3—O15i104.57 (10)
O13—Ti1—O3090.73 (8)O13—P3—O14112.25 (10)
O13—Ti1—O3287.78 (8)O13—P3—O15i113.01 (10)
O26—Ti1—O3088.55 (8)O14—P3—O15i111.26 (10)
O26—Ti1—O3292.26 (8)O2—P4—O16104.83 (10)
O30—Ti1—O32178.32 (8)O2—P4—O17109.64 (10)
O8—Ti2—O2092.12 (7)O2—P4—O18ii107.21 (10)
O8—Ti2—O2290.36 (7)O16—P4—O17111.40 (10)
O8—Ti2—O2791.05 (7)O16—P4—O18ii110.87 (10)
O8—Ti2—O9179.46 (9)O17—P4—O18ii112.51 (10)
O8—Ti2—O1688.28 (7)O3—P5—O19ii104.76 (9)
O20—Ti2—O2289.12 (7)O3—P5—O20105.89 (10)
O20—Ti2—O2790.66 (7)O3—P5—O21110.24 (9)
O20—Ti2—O987.34 (8)O19ii—P5—O20110.81 (10)
O20—Ti2—O16179.36 (7)O19ii—P5—O21111.04 (10)
O22—Ti2—O27178.58 (7)O20—P5—O21113.61 (10)
O22—Ti2—O989.68 (7)O3—P6—O23106.87 (9)
O22—Ti2—O1690.37 (7)O3—P6—O22105.60 (9)
O27—Ti2—O988.91 (7)O3—P6—O24107.59 (10)
O27—Ti2—O1689.84 (7)O23—P6—O22113.25 (9)
O9—Ti2—O1692.26 (8)O23—P6—O24112.14 (10)
O12—Ti3—O2192.40 (8)O22—P6—O24110.93 (10)
O12—Ti3—O2486.61 (8)O4—P7—O25105.12 (10)
O12—Ti3—O2590.05 (8)O4—P7—O27106.65 (10)
O12—Ti3—O31178.86 (8)O4—P7—O26109.13 (10)
O12—Ti3—O1592.68 (7)O25—P7—O27112.03 (10)
O21—Ti3—O2488.79 (8)O25—P7—O26110.78 (10)
O21—Ti3—O2590.81 (7)O27—P7—O26112.72 (10)
O21—Ti3—O3188.15 (8)O4—P8—O28108.67 (9)
O21—Ti3—O15174.61 (7)O4—P8—O30105.84 (10)
O24—Ti3—O25176.62 (8)O4—P8—O29105.63 (9)
O24—Ti3—O3192.40 (8)O28—P8—O30113.37 (10)
O24—Ti3—O1589.71 (8)O28—P8—O29111.50 (9)
O25—Ti3—O3190.94 (8)O30—P8—O29111.33 (10)
O25—Ti3—O1590.99 (7)O5—P9—O31107.30 (12)
O31—Ti3—O1586.75 (7)O5—P9—O31iii107.30 (12)
O14—Ti4—O1890.28 (7)O5—P9—O31iv107.30 (11)
O14—Ti4—O1989.96 (7)O31iii—P9—O31111.55 (11)
O14—Ti4—O28177.84 (8)O31iii—P9—O31iv111.55 (11)
O14—Ti4—O2991.53 (7)O31iv—P9—O31111.55 (11)
O14—Ti4—O3388.20 (7)O5—P10—O32iii107.33 (12)
O18—Ti4—O1991.52 (7)O5—P10—O32iv107.33 (12)
O18—Ti4—O2887.69 (7)O5—P10—O32107.33 (12)
O18—Ti4—O29178.10 (8)O32iii—P10—O32iv111.53 (11)
O18—Ti4—O3390.25 (7)O32iii—P10—O32111.53 (11)
O19—Ti4—O2890.82 (7)O32iv—P10—O32111.53 (11)
O19—Ti4—O2989.06 (7)O6—P11—O33106.89 (7)
O19—Ti4—O33177.45 (8)O6—P11—O33106.89 (7)
O28—Ti4—O2990.50 (7)O6—P11—O33ii106.89 (7)
O28—Ti4—O3391.09 (7)O33—P11—O33111.93 (10)
O29—Ti4—O3389.23 (7)O33—P11—O33ii111.93 (10)
O10—Ti5—O1090.71 (8)O33—P11—O33ii111.93 (10)
O10—Ti5—O1090.71 (8)P1—O1—P2144.51 (13)
O10—Ti5—O17177.28 (8)P3—O2—P4143.04 (12)
O10—Ti5—O1789.15 (7)P5—O3—P6141.21 (12)
O10—Ti5—O1792.01 (7)P7—O4—P8143.41 (12)
O10—Ti5—O1090.71 (8)P9i—O5—P10180.0 (2)
O10—Ti5—O1792.01 (8)P11—O6—P11180
O10—Ti5—O17177.28 (8)Ti1—O7—P1153.63 (12)
O10—Ti5—O1789.15 (7)Ti2—O8—P1160.44 (12)
O10—Ti5—O1789.15 (8)P1—O9—Ti2163.15 (12)
O10—Ti5—O1792.01 (8)Ti5—O10—P2155.30 (12)
O10—Ti5—O17177.28 (9)Ti1—O11—P2165.23 (13)
O17—Ti5—O1788.14 (7)Ti3—O12—P2169.56 (13)
O17—Ti5—O1788.14 (7)Ti1—O13—P3153.23 (12)
O17—Ti5—O1788.14 (7)Ti4—O14—P3141.73 (11)
O23—Ti6—O2390.37 (7)P3—O15—Ti3149.73 (11)
O23—Ti6—O2390.37 (7)P4—O16—Ti2148.01 (11)
O23—Ti6—O23180P4—O17—Ti5155.94 (12)
O23—Ti6—O2389.63 (7)Ti4—O18—P4151.12 (12)
O23—Ti6—O2389.63 (7)Ti4—O19—P5144.35 (10)
O23—Ti6—O2390.37 (7)Ti2—O20—P5143.55 (11)
O23—Ti6—O2389.63 (7)Ti3—O21—P5154.83 (11)
O23—Ti6—O23180Ti2—O22—P6139.78 (10)
O23—Ti6—O2389.63 (7)Ti6—O23—P6146.34 (11)
O23—Ti6—O2389.63 (7)Ti3—O24—P6153.08 (12)
O23—Ti6—O2389.63 (7)Ti3—O25—P7156.46 (12)
O23—Ti6—O23180Ti1—O26—P7vi156.41 (12)
O23—Ti6—O2390.37 (7)Ti2—O27—P7i148.43 (11)
O23—Ti6—O2390.37 (7)Ti4—O28—P8141.15 (10)
O23—Ti6—O2390.37 (7)Ti4—O29—P8vi139.57 (10)
O1—P1—O7104.68 (10)Ti1—O30—P8ii153.01 (12)
O1—P1—O8108.25 (10)Ti3—O31—P9152.29 (13)
O1—P1—O9108.78 (10)Ti1—O32—P10161.00 (14)
O7—P1—O8112.02 (10)Ti4—O33—P11139.09 (11)
O7—P1—O9110.75 (10)
Symmetry codes: (i) x+1/2, y, z+1/2; (ii) z+1/2, x+1/2, y; (iii) y, z, x; (iv) z, x, y; (v) x+1/2, y+1/2, z; (vi) y+1/2, z, x+1/2.

Experimental details

Crystal data
Chemical formulaTiP2O7
Mr221.82
Crystal system, space groupCubic, Pa3
Temperature (K)293
a (Å)23.5340 (5)
V3)13034.3 (5)
Z108
Radiation typeSynchrotron x-ray vertical wiggler, λ = 0.8522 (5) Å
µ (mm1)3.74
Crystal size (mm)0.06 × 0.02 × 0.02
Data collection
DiffractometerBruker SMART area 1000 CCD
diffractometer
Absorption correctionMulti-scan
SADABS (Bruker, 1998)
Tmin, Tmax0.619, 0.928
No. of measured, independent and
observed [F > 4σ(F)] reflections
82262, 8970, 8363
Rint0.099
(sin θ/λ)max1)0.808
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.059, 2.78
No. of reflections8563
No. of parameters408
Δρmax, Δρmin (e Å3)1.14, 1.29

Computer programs: SMART-NT (Bruker, 1998), SAINT+ (Bruker, 1999), Xtal3.7 (Hall et al., 2000) DIFDAT ADDREF ABSORB SORTRF, SHELXS97 (Sheldrick, 1997), Xtal3.7 (Hall et al., 2000) CRYLSQ, ORTEPIII (Burnett & Johnson, 1996), Xtal3.7 (Hall et al., 2000) BONDLA ATABLE CIFIO.

Selected geometric parameters (Å, º) top
P1—O11.5770 (19)P7—O41.5662 (19)
P2—O11.578 (2)P8—O41.5815 (18)
P3—O21.5805 (18)P9—O51.541 (2)
P4—O21.5770 (19)P10—O51.536 (2)
P5—O31.5726 (17)P11—O61.5332 (5)
P6—O31.5707 (18)
P1—O1—P2144.51 (13)P7—O4—P8143.41 (12)
P3—O2—P4143.04 (12)P9i—O5—P10180.0 (2)
P5—O3—P6141.21 (12)P11—O6—P11180
Symmetry code: (i) x+1/2, y, z+1/2.
Intensity statistics for all measured reflections. top
I/σ(I) intervallNumber of supperlatticeNumber of sublattice
(h,k,l ≠ 3n) reflections(h,k,l = 3n) reflections
0.00 - 1.007467231
1.00 - 2.00457258
2.00 - 4.00825789
4.00 - 8.0011641135
8.00 - 16.0017509330
16.00 - 32.0018779525
32.00 - 64.009022591
64.00 - 128.001957652
128.00 - 256.0028419
 

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