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Crystals of pentalanthanum pentatitanium heptadecaoxide (La5Ti5O17 with 0.3% oxy­gen excess, or LaTiO3.41) have been synthesized by floating-zone melting, and the structure has been solved using single-crystal X-ray diffraction intensities. The monoclinic (P21/c) structure consists of perovskite-like slabs of vertex-sharing TiO6 octahedra, which are separated by additional oxy­gen layers. The slabs are five octahedra wide. Due to the adjustment of the TiO6 octahedra to meet the coordination requirements of the La3+ cations, a superstructure develops along the a axis.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102023612/bc1002sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270102023612/bc1002Isup2.hkl
Contains datablock I

Comment top

A group of compounds with the chemical formula AnBnO3n+2 (A is Sr, La or Ca, and B is Nb or Ti) have been studied recently because of their interesting electronic properties (Lichtenberg et al., 2001; Kuntscher, Schuppler et al., 2002; Kuntscher, van der Marel et al., 2002). The crystal structures of the members of this family consist of (110) slabs of the perovskite structure that are separated by layers of additional O atoms. The width of the slabs in terms of the number of octahedra corresponds to the value of n in the chemical formula. The ideal formula of the n = 5 member in the LaTiOx system is La5Ti5O17, or LaTiO3.40, but this compound exists in the homogeneity range 3.40 < x < 3.42, as revealed by powder X-ray diffraction, high-resolution electron microscopy and thermogravimetry (Lichtenberg et al., 1991). The composition of the title compound, LaTiO3.41 (0.3% oxygen excess), has been determined by thermogravimetric oxidation (Lichtenberg et al., 2001). It is not clear if this nonstoichiometry corresponds to cation deficiency or oxygen excess, but there are indications for the latter in related niobates with n = 4 (Lichtenberg et al., 2001).

The single-crystal used for the present X-ray diffraction data collection was broken off a larger piece of material synthesized by floating zone melting, with a composition of LaTiO3.41 (Lichtenberg et al., 2001). Due to its layered structure, the material shows a perfect (001) cleavage, leading to the production of extremely thin plates when preparing single crystals. This property makes the correction for absorption effects indispensable and leads to an increased mosaic spread of crystals. In conjunction with the large cell dimension in the c direction, the mosaic spread limits the number of scans useful for obtaining integrated intensities. Depending on the scan direction in reciprocal space, some scans contained intensity from more than one reflection. These scans were recognized and discarded.

The chemical composition of the compound is slightly non-stoichiometric, but the presence of cation vacancies, or alternatively of excess oxygen, could not be analyzed with the data presented here. The anisotropic displacement parameters describe very oblate ellipsoids, which is due either to the absence of some reflections or to insufficient absorption correction. Hence, the physical meaning of the displacement parameters cannot be discussed. Their strong correlation with occupancy parameters also prohibits the refinement of the latter.

The refinement of the crystal structure shows that it consists of perovskite-type slabs five octahedra wide (Fig. 1). The topology proposed by Williams et al. (1991), based on electron microscopic observations, is confirmed, and the position estimates of Williams et al. (1991) are replaced by more precise values referring to the correct unit cell and symmetry. The unit-cell volume of LaTiO3.41 is approximately twice as large as that of SrNbO3.41 (Abrahams et al., 1998), while the symmetry is monoclinic for the former compared with orthorhombic for the latter. The differences between these two isotypic structures can be understood from the different chemical compositions. Divalent Sr is replaced by trivalent La, and nearly tetravalent Ti replaces approximately pentavalent Nb, thus transferring bond strength from the octahedral sites to the A sites. This substitution, in conjunction with differences in radii, distorts the oxygen environment of the metal atoms, causing local strain. This strain, in turn, is relieved by a commensurate modulation of the structure, leading to a twofold superstructure in the [100] direction of LaTiO3.41 as compared with SrNbO3.41. Indeed, the reflections with odd h indices have only 20% of the intensities of the reflections with even h indices. This is reflected by the atomic coordinates, whereby a counterpart near (x + 1/2, y, z) can be found for every atom site at (x, y, z).

The difference between orthorhombic SrNbO3.41 and monoclinic LaTiO3.41 can best be seen in the coordination of the A sites. Surprisingly, the major differences are not found for atoms near the additional oxygen layer, but for those in positions intermediate between the oxygen layer and the centre of the octahedral slab, i.e. atoms La2 and La3 (Fig. 1). While in SrNbO3.41 the Sr atoms in this position are all symmetry equivalent and occupy the centre of the coordinating cuboctahedron (Fig. 2a), atoms La2 and La3 in LaTiO3.41 are shifted away from the centres of their coordination polyhedra (Fig. 2 b). The shifts of the La2 and La3 positions are accompanied by rotations of the octahedra, in agreement with the lower symmetry of the La compound.

The distortions of the coordination polyhedra can be analyzed in terms of average metal-oxygen bond lengths and angles and their standard deviations (Table 1). The TiO6 octahedra in the centre of the perovskite slabs are virtually undistorted with respect to bond lengths and angles. The distortion grows as the octahedra approach the rim of the slab, as shown by the increasing standard deviations of the mean Ti—O bond lengths (Table 1). No such significant difference can be found with respect to the average O—Ti—O angles. This agrees well with the situation found in SrNbO3.41 (Abrahams et al., 1998), where the bond-length distortion of the corresponding NbO6 octahedra is almost identical and the angular distortion grows only by a small amount when approaching the rim of the perovskite slab. While the La sites within the octahedral slabs (La1, La2, and La3) allow the description of their coordination by a distorted cuboctahedron, such a description is useless for La4 and La5. The latter are at the rim of the slabs, and consequently, two of the twelve O atoms of the cuboctahedron are missing. The actual positions of La4 and La5 are shifted away from the would be centre of the cuboctahedron into the direction of the opposite slab. The resulting irregular coordination is similar to that of Sr in Sr2Nb2O7 (Daniels et al., 2002) and is tenfold for La4 and [seven + three]-fold for La5.

Experimental top

Please provide brief details of compound synthesis and crystal growth.

Refinement top

In the difference Fourier synthesis, the highest peak (3.22 e Å−1) is at 0.8322, 0.5566, 0.1985 [0.56 Å from La5] and the deepest hole (−3.16 e Å−1) is at 0.3587, 0.4674, 0.1929 [0.59 Å from La4].

Computing details top

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: HELENA (Spek, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The crystal structure of LaTiO3.41 viewed along b. Large grey spheres represent La, smaller light-grey spheres are Ti, and the smallest and dark-grey spheres represent O atoms. The unit cell is outlined.
[Figure 2] Fig. 2. The coordination of (a) Sr3 in SrNbO3.41 viewed along a* and (b) La2 and La3 in LaTiO3.41 viewed along c*. The view directions relative to the topology are the same in both cases; only the unit-cell settings are different.
pentalanthanum pentatitanium heptadecaoxide top
Crystal data top
La5Ti5O17F(000) = 2124
Mr = 1205.90Dx = 5.906 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71069 Å
Hall symbol: -p 2ybcCell parameters from 25 reflections
a = 7.8580 (11) Åθ = 18.0–22.7°
b = 5.5281 (9) ŵ = 18.25 mm1
c = 31.449 (5) ÅT = 293 K
β = 97.166 (16)°Irregular plate, dark-blue-black
V = 1355.5 (4) Å30.10 × 0.08 × 0.01 mm
Z = 4
Data collection top
Enraf-Nonius MACH3
diffractometer
5164 reflections with I > 2σ(I)
Radiation source: Nonius rotating anode generatorRint = 0.053
Graphite monochromatorθmax = 36.9°, θmin = 1.3°
ω/2θ scansh = 1212
Absorption correction: ψ scan
(Herrendorf, 1992)
k = 79
Tmin = 0.31, Tmax = 0.89l = 5350
21243 measured reflections3 standard reflections every 60 min
6456 independent reflections intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.039 w = 1/[σ2(Fo2) + (0.0238P)2 + 11.7499P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.082(Δ/σ)max = 0.002
S = 1.13Δρmax = 3.22 e Å3
6456 reflectionsΔρmin = 3.16 e Å3
248 parametersExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.00024 (2)
Crystal data top
La5Ti5O17V = 1355.5 (4) Å3
Mr = 1205.90Z = 4
Monoclinic, P21/cMo Kα radiation
a = 7.8580 (11) ŵ = 18.25 mm1
b = 5.5281 (9) ÅT = 293 K
c = 31.449 (5) Å0.10 × 0.08 × 0.01 mm
β = 97.166 (16)°
Data collection top
Enraf-Nonius MACH3
diffractometer
5164 reflections with I > 2σ(I)
Absorption correction: ψ scan
(Herrendorf, 1992)
Rint = 0.053
Tmin = 0.31, Tmax = 0.893 standard reflections every 60 min
21243 measured reflections intensity decay: none
6456 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0390 restraints
wR(F2) = 0.082 w = 1/[σ2(Fo2) + (0.0238P)2 + 11.7499P]
where P = (Fo2 + 2Fc2)/3
S = 1.13Δρmax = 3.22 e Å3
6456 reflectionsΔρmin = 3.16 e Å3
248 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
La10.25173 (3)0.00052 (5)0.502664 (9)0.00695 (6)
La20.29695 (3)0.00424 (5)0.092757 (9)0.00526 (6)
La30.79311 (3)0.00169 (5)0.087115 (9)0.00665 (6)
La40.35508 (4)0.04768 (6)0.294718 (10)0.00941 (6)
La50.14382 (3)0.08565 (5)0.284710 (10)0.00608 (6)
Ti10.50000.00000.00000.00393 (19)
Ti20.00000.00000.00000.00390 (19)
Ti30.54528 (10)0.50568 (16)0.09322 (3)0.00388 (13)
Ti40.04726 (10)0.50697 (16)0.09266 (3)0.00387 (13)
Ti50.08704 (11)0.03592 (16)0.17749 (3)0.00440 (14)
Ti60.59026 (11)0.03939 (16)0.17870 (3)0.00419 (14)
O10.5508 (5)0.2810 (7)0.03715 (12)0.0084 (6)
O20.0135 (5)0.2795 (7)0.03752 (12)0.0081 (6)
O30.5060 (5)0.7765 (7)0.05044 (12)0.0072 (6)
O40.0445 (5)0.7748 (7)0.04998 (13)0.0090 (7)
O50.0914 (4)0.2992 (7)0.21231 (12)0.0063 (6)
O60.6208 (5)0.3106 (7)0.20898 (14)0.0100 (7)
O70.1230 (4)0.8153 (7)0.22172 (12)0.0057 (6)
O80.6013 (4)0.8224 (7)0.22483 (12)0.0057 (6)
O90.0476 (4)0.1963 (7)0.12086 (12)0.0061 (6)
O100.5725 (4)0.1943 (6)0.12080 (12)0.0053 (6)
O110.3366 (4)0.0700 (8)0.17234 (12)0.0095 (7)
O120.8350 (4)0.0361 (7)0.16952 (12)0.0070 (6)
O130.1136 (5)0.7135 (7)0.13701 (12)0.0085 (6)
O140.5240 (5)0.7083 (7)0.13823 (13)0.0093 (7)
O150.7944 (5)0.5414 (7)0.08964 (13)0.0097 (7)
O160.2904 (4)0.4432 (7)0.08152 (12)0.0068 (6)
O170.7499 (4)0.9488 (7)0.00103 (12)0.0080 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
La10.00592 (11)0.00706 (12)0.00789 (12)0.00014 (9)0.00090 (8)0.00118 (10)
La20.00332 (10)0.00592 (12)0.00659 (11)0.00016 (8)0.00076 (8)0.00086 (9)
La30.00390 (11)0.00764 (12)0.00849 (12)0.00017 (9)0.00110 (8)0.00144 (9)
La40.00330 (11)0.00955 (13)0.01566 (14)0.00069 (9)0.00225 (9)0.00421 (10)
La50.00309 (10)0.00519 (11)0.01000 (12)0.00014 (9)0.00094 (8)0.00143 (9)
Ti10.0026 (4)0.0045 (5)0.0046 (4)0.0007 (4)0.0001 (3)0.0002 (4)
Ti20.0028 (4)0.0038 (5)0.0049 (4)0.0007 (4)0.0001 (3)0.0003 (4)
Ti30.0038 (3)0.0032 (3)0.0047 (3)0.0001 (3)0.0005 (2)0.0006 (3)
Ti40.0039 (3)0.0032 (3)0.0046 (3)0.0003 (3)0.0005 (2)0.0002 (3)
Ti50.0044 (3)0.0035 (3)0.0054 (3)0.0005 (3)0.0010 (2)0.0004 (3)
Ti60.0047 (3)0.0029 (3)0.0049 (3)0.0005 (3)0.0004 (2)0.0001 (3)
O10.0083 (15)0.0084 (16)0.0084 (16)0.0001 (12)0.0009 (12)0.0003 (13)
O20.0107 (15)0.0073 (16)0.0063 (16)0.0004 (12)0.0005 (12)0.0026 (13)
O30.0092 (15)0.0066 (15)0.0059 (15)0.0011 (12)0.0011 (11)0.0006 (13)
O40.0089 (15)0.0101 (17)0.0080 (16)0.0001 (13)0.0006 (12)0.0026 (14)
O50.0060 (14)0.0036 (15)0.0096 (17)0.0005 (11)0.0018 (11)0.0018 (12)
O60.0032 (14)0.0083 (17)0.018 (2)0.0021 (12)0.0001 (12)0.0042 (15)
O70.0048 (14)0.0059 (15)0.0064 (16)0.0008 (11)0.0001 (11)0.0036 (12)
O80.0047 (14)0.0061 (15)0.0065 (16)0.0005 (11)0.0018 (11)0.0009 (12)
O90.0050 (14)0.0064 (15)0.0071 (16)0.0018 (11)0.0012 (11)0.0023 (12)
O100.0071 (14)0.0010 (13)0.0078 (16)0.0008 (11)0.0011 (11)0.0002 (12)
O110.0010 (13)0.0179 (19)0.0093 (16)0.0015 (13)0.0005 (11)0.0003 (14)
O120.0019 (13)0.0107 (16)0.0086 (15)0.0010 (12)0.0012 (10)0.0014 (13)
O130.0122 (16)0.0064 (15)0.0067 (16)0.0009 (13)0.0005 (12)0.0021 (13)
O140.0105 (16)0.0086 (16)0.0088 (17)0.0031 (13)0.0008 (12)0.0003 (13)
O150.0054 (14)0.0099 (17)0.0136 (17)0.0013 (12)0.0004 (12)0.0001 (14)
O160.0038 (13)0.0079 (16)0.0089 (15)0.0008 (11)0.0015 (11)0.0001 (13)
O170.0026 (13)0.0094 (16)0.0119 (17)0.0002 (12)0.0000 (12)0.0010 (14)
Geometric parameters (Å, º) top
La1—O1i2.435 (4)Ti3—O12.162 (4)
La1—O2ii2.450 (4)Ti3—La2xviii3.3378 (10)
La1—O17i2.479 (4)Ti3—La3xviii3.3825 (10)
La1—O16iii2.480 (4)Ti3—La1xiv3.4343 (11)
La1—O1iii2.743 (4)Ti3—La1v3.5832 (10)
La1—O2iii2.756 (4)Ti4—O131.827 (4)
La1—O4iii2.791 (4)Ti4—O91.932 (4)
La1—O3iii2.801 (4)Ti4—O15xii1.987 (4)
La1—O15i2.889 (4)Ti4—O41.997 (4)
La1—O17iv3.050 (4)Ti4—O162.016 (4)
La1—O4ii3.081 (4)Ti4—O22.147 (4)
La1—O3i3.088 (4)Ti4—La2xviii3.3391 (10)
La1—Ti1v3.3879 (5)Ti4—La3xix3.3781 (10)
La1—Ti2vi3.3915 (5)Ti4—La1xiv3.4248 (10)
La1—Ti1i3.3926 (5)Ti4—La3xii3.4256 (10)
La2—O102.489 (4)Ti4—La1vi3.5709 (11)
La2—O162.498 (4)Ti5—O51.819 (4)
La2—O92.506 (4)Ti5—O7vii1.845 (4)
La2—O112.517 (4)Ti5—O91.979 (4)
La2—O3vii2.547 (4)Ti5—O111.996 (4)
La2—O4vii2.564 (4)Ti5—O12xii2.005 (4)
La2—O13vii2.636 (4)Ti5—O13vii2.215 (4)
La2—O14vii2.668 (4)Ti5—La5ii3.3820 (10)
La2—O17viii2.879 (4)Ti5—La3xii3.4366 (11)
La2—O16vii3.075 (4)Ti5—La4ii3.4678 (10)
La2—O23.221 (4)Ti5—La4vi3.5700 (10)
La2—O13.224 (4)Ti6—O61.776 (4)
La2—Ti53.3117 (10)Ti6—O8vii1.876 (4)
La2—Ti63.3350 (11)Ti6—O111.986 (4)
La2—Ti3vii3.3378 (10)Ti6—O102.001 (4)
La3—O102.391 (3)Ti6—O122.024 (3)
La3—O9ix2.399 (4)Ti6—O14vii2.253 (4)
La3—O15vii2.546 (4)Ti6—La5i3.3737 (10)
La3—O122.580 (4)Ti6—La4ii3.4479 (10)
La3—O3vii2.705 (4)Ti6—La4vi3.5206 (10)
La3—O4x2.723 (4)Ti6—La4ix3.6204 (11)
La3—O17vii2.766 (4)O1—La1v2.435 (4)
La3—O2ix2.773 (4)O1—La1xiv2.743 (4)
La3—O12.781 (4)O2—La1vi2.450 (4)
La3—O152.985 (4)O2—La1xiv2.756 (4)
La3—O13x3.218 (4)O2—La3xii2.773 (4)
La3—O14vii3.246 (4)O3—Ti1xviii2.007 (4)
La3—Ti13.3521 (7)O3—La2xviii2.547 (4)
La3—Ti2ix3.3557 (6)O3—La3xviii2.705 (4)
La3—Ti4x3.3781 (10)O3—La1xiv2.801 (4)
La4—O7ii2.453 (4)O3—La1v3.088 (4)
La4—O6ii2.456 (4)O4—Ti2xviii2.001 (4)
La4—O8ii2.476 (4)O4—La2xviii2.564 (4)
La4—O8xi2.512 (4)O4—La3xix2.723 (4)
La4—O5ii2.519 (4)O4—La1xiv2.791 (4)
La4—O14ii2.774 (4)O4—La1vi3.081 (4)
La4—O11ii2.834 (4)O5—La5vi2.445 (4)
La4—O13ii2.834 (4)O5—La4vi2.519 (4)
La4—O6xii3.048 (4)O5—La5ii4.362 (4)
La4—O11vi3.065 (4)O6—La5v2.384 (4)
La4—Ti6vi3.4479 (10)O6—La4vi2.456 (4)
La4—Ti5vi3.4678 (10)O6—La4ix3.048 (4)
La4—Ti6ii3.5206 (10)O6—La5i4.408 (4)
La4—Ti5ii3.5700 (10)O7—Ti5xviii1.845 (4)
La4—Ti6xii3.6204 (11)O7—La5vi2.438 (4)
La5—O6i2.384 (4)O7—La4vi2.453 (4)
La5—O7ii2.438 (4)O7—La5xviii2.471 (4)
La5—O8i2.442 (3)O8—Ti6xviii1.876 (4)
La5—O5ii2.445 (4)O8—La5v2.442 (3)
La5—O7vii2.471 (4)O8—La4vi2.476 (4)
La5—O12v2.532 (4)O8—La4xx2.512 (4)
La5—O52.552 (4)O9—La3xii2.399 (4)
La5—Ti53.3572 (10)O9—La4vi3.880 (4)
La5—Ti6v3.3737 (10)O9—La5vi4.102 (4)
La5—Ti5vi3.3820 (10)O10—La4vi3.864 (4)
La5—O14i3.401 (4)O10—La5v4.102 (4)
La5—O13ii3.449 (4)O11—La4vi2.834 (4)
La5—O12i3.722 (4)O11—La4ii3.065 (4)
La5—Ti6i3.7696 (10)O11—La4ix4.286 (4)
La5—Ti5ii3.8050 (10)O12—Ti5ix2.005 (3)
Ti1—O1xiii1.955 (4)O12—La5i2.532 (4)
Ti1—O11.955 (4)O12—La5v3.722 (4)
Ti1—O17viii1.989 (3)O12—La5ix4.156 (4)
Ti1—O17vii1.989 (3)O12—La4ix4.407 (4)
Ti1—O3vii2.007 (4)O13—Ti5xviii2.215 (4)
Ti1—O3viii2.007 (4)O13—La2xviii2.636 (4)
Ti1—La3xiii3.3521 (7)O13—La4vi2.834 (4)
Ti1—La1i3.3879 (5)O13—La3xix3.218 (4)
Ti1—La1xiv3.3879 (5)O13—La5vi3.449 (4)
Ti1—La1v3.3926 (5)O14—Ti6xviii2.253 (4)
Ti1—La1xv3.3926 (5)O14—La2xviii2.668 (4)
Ti2—O21.955 (4)O14—La4vi2.774 (4)
Ti2—O2xvi1.955 (4)O14—La3xviii3.246 (4)
Ti2—O17xi1.982 (3)O14—La5v3.401 (4)
Ti2—O17viii1.982 (3)O15—Ti4ix1.987 (4)
Ti2—O4vii2.001 (4)O15—La3xviii2.546 (4)
Ti2—O4xvii2.001 (4)O15—La1v2.889 (4)
Ti2—La3xii3.3557 (6)O15—La5v3.928 (4)
Ti2—La3xiii3.3557 (6)O16—La1xiv2.480 (4)
Ti2—La1xiv3.3915 (5)O16—La2xviii3.075 (4)
Ti2—La1ii3.3915 (5)O16—La4vi3.905 (4)
Ti2—La1xv3.3962 (5)O17—Ti2xx1.982 (3)
Ti2—La1vi3.3962 (5)O17—Ti1xviii1.989 (3)
Ti3—O141.829 (4)O17—La1v2.479 (4)
Ti3—O101.927 (4)O17—La3xviii2.766 (4)
Ti3—O151.984 (4)O17—La2viii2.879 (4)
Ti3—O32.011 (4)O17—La1xxi3.050 (4)
Ti3—O162.021 (4)
O1i—La1—O2ii88.92 (13)O17viii—Ti2—O4vii90.03 (15)
O1i—La1—O17i119.30 (12)O2—Ti2—O4xvii88.00 (17)
O2ii—La1—O17i119.09 (12)O2xvi—Ti2—O4xvii92.00 (17)
O1i—La1—O16iii124.76 (12)O17xi—Ti2—O4xvii90.03 (15)
O2ii—La1—O16iii124.66 (12)O17viii—Ti2—O4xvii89.97 (15)
O17i—La1—O16iii83.98 (12)O4vii—Ti2—O4xvii180.00 (15)
O1i—La1—O1iii81.56 (14)O14—Ti3—O10102.39 (17)
O2ii—La1—O1iii170.17 (12)O14—Ti3—O1599.73 (17)
O17i—La1—O1iii64.54 (12)O10—Ti3—O1593.40 (16)
O16iii—La1—O1iii63.73 (12)O14—Ti3—O392.33 (17)
O1i—La1—O2iii170.48 (12)O10—Ti3—O3164.85 (16)
O2ii—La1—O2iii81.85 (13)O15—Ti3—O387.59 (16)
O17i—La1—O2iii64.20 (11)O14—Ti3—O1693.53 (16)
O16iii—La1—O2iii63.34 (12)O10—Ti3—O1688.93 (15)
O1iii—La1—O2iii107.56 (12)O15—Ti3—O16165.70 (17)
O1i—La1—O4iii117.00 (13)O3—Ti3—O1686.53 (15)
O2ii—La1—O4iii62.86 (12)O14—Ti3—O1175.03 (17)
O17i—La1—O4iii123.67 (12)O10—Ti3—O180.89 (15)
O16iii—La1—O4iii62.75 (12)O15—Ti3—O183.71 (16)
O1iii—La1—O4iii123.89 (12)O3—Ti3—O184.20 (16)
O2iii—La1—O4iii60.52 (11)O16—Ti3—O182.74 (15)
O1i—La1—O3iii62.99 (12)O13—Ti4—O9102.77 (17)
O2ii—La1—O3iii116.87 (12)O13—Ti4—O15xii99.51 (17)
O17i—La1—O3iii124.01 (11)O9—Ti4—O15xii92.94 (16)
O16iii—La1—O3iii62.74 (11)O13—Ti4—O491.61 (17)
O1iii—La1—O3iii60.65 (11)O9—Ti4—O4165.15 (17)
O2iii—La1—O3iii123.52 (11)O15xii—Ti4—O488.27 (16)
O4iii—La1—O3iii80.83 (11)O13—Ti4—O1693.18 (16)
O1i—La1—O15i61.99 (12)O9—Ti4—O1688.69 (15)
O2ii—La1—O15i61.89 (12)O15xii—Ti4—O16166.50 (17)
O17i—La1—O15i84.33 (12)O4—Ti4—O1686.79 (16)
O16iii—La1—O15i168.31 (12)O13—Ti4—O2174.82 (16)
O1iii—La1—O15i110.90 (11)O9—Ti4—O280.65 (16)
O2iii—La1—O15i111.04 (11)O15xii—Ti4—O284.09 (16)
O4iii—La1—O15i124.75 (11)O4—Ti4—O284.75 (16)
O3iii—La1—O15i124.98 (11)O16—Ti4—O282.95 (15)
O10—La2—O1667.37 (12)O5—Ti5—O7vii94.89 (17)
O10—La2—O9111.33 (12)O5—Ti5—O999.93 (17)
O16—La2—O966.96 (11)O7vii—Ti5—O9165.18 (17)
O10—La2—O1165.26 (12)O5—Ti5—O1191.63 (16)
O16—La2—O1188.68 (13)O7vii—Ti5—O1193.66 (16)
O9—La2—O1165.31 (12)O9—Ti5—O1185.96 (15)
O10—La2—O3vii78.78 (12)O5—Ti5—O12xii100.27 (16)
O16—La2—O3vii113.61 (12)O7vii—Ti5—O12xii91.09 (16)
O9—La2—O3vii168.12 (12)O9—Ti5—O12xii86.29 (15)
O11—La2—O3vii126.12 (12)O11—Ti5—O12xii166.77 (17)
O10—La2—O4vii168.01 (12)O5—Ti5—O13vii173.51 (15)
O16—La2—O4vii113.36 (12)O7vii—Ti5—O13vii83.39 (16)
O9—La2—O4vii78.93 (12)O9—Ti5—O13vii81.88 (15)
O11—La2—O4vii126.24 (12)O11—Ti5—O13vii82.26 (16)
O3vii—La2—O4vii90.37 (12)O12xii—Ti5—O13vii86.03 (15)
O10—La2—O13vii125.63 (12)O6—Ti6—O8vii97.77 (19)
O16—La2—O13vii131.14 (12)O6—Ti6—O1192.80 (17)
O9—La2—O13vii64.72 (12)O8vii—Ti6—O1194.68 (16)
O11—La2—O13vii65.13 (12)O6—Ti6—O1096.66 (18)
O3vii—La2—O13vii115.15 (12)O8vii—Ti6—O10165.56 (16)
O4vii—La2—O13vii63.70 (12)O11—Ti6—O1085.22 (15)
O10—La2—O14vii65.08 (12)O6—Ti6—O12100.57 (16)
O16—La2—O14vii131.78 (12)O8vii—Ti6—O1291.45 (15)
O9—La2—O14vii125.07 (12)O11—Ti6—O12164.41 (17)
O11—La2—O14vii64.70 (12)O10—Ti6—O1285.29 (15)
O3vii—La2—O14vii64.19 (12)O6—Ti6—O14vii174.17 (16)
O4vii—La2—O14vii114.80 (12)O8vii—Ti6—O14vii84.40 (16)
O13vii—La2—O14vii74.77 (12)O11—Ti6—O14vii81.61 (16)
O10—La2—O17viii107.76 (11)O10—Ti6—O14vii81.29 (15)
O16—La2—O17viii75.82 (12)O12—Ti6—O14vii84.75 (15)
O9—La2—O17viii107.36 (11)Ti1—O1—Ti3157.0 (2)
O11—La2—O17viii164.50 (13)Ti1—O1—La1v100.63 (16)
O3vii—La2—O17viii62.43 (11)Ti3—O1—La1v102.25 (15)
O4vii—La2—O17viii62.02 (11)Ti1—O1—La1xiv90.71 (14)
O13vii—La2—O17viii125.60 (11)Ti3—O1—La1xiv88.06 (13)
O14vii—La2—O17viii126.44 (11)La1v—O1—La1xiv98.44 (13)
O10—La3—O9ix102.40 (12)Ti1—O1—La388.33 (14)
O10—La3—O15vii115.56 (12)Ti3—O1—La386.56 (13)
O9ix—La3—O15vii115.77 (12)La1v—O1—La397.59 (12)
O10—La3—O1266.41 (12)La1xiv—O1—La3163.84 (16)
O9ix—La3—O1266.24 (12)Ti2—O2—Ti4158.0 (2)
O15vii—La3—O1283.57 (13)Ti2—O2—La1vi100.27 (16)
O10—La3—O3vii77.40 (12)Ti4—O2—La1vi101.72 (15)
O9ix—La3—O3vii178.87 (12)Ti2—O2—La1xiv90.46 (13)
O15vii—La3—O3vii63.46 (12)Ti4—O2—La1xiv87.69 (13)
O12—La3—O3vii112.72 (11)La1vi—O2—La1xiv98.15 (13)
O10—La3—O4x178.81 (12)Ti2—O2—La3xii88.66 (14)
O9ix—La3—O4x77.70 (12)Ti4—O2—La3xii87.27 (13)
O15vii—La3—O4x63.43 (12)La1vi—O2—La3xii97.43 (12)
O12—La3—O4x112.64 (11)La1xiv—O2—La3xii164.30 (16)
O3vii—La3—O4x102.48 (12)Ti1xviii—O3—Ti3166.9 (2)
O10—La3—O17vii119.08 (11)Ti1xviii—O3—La2xviii99.61 (15)
O9ix—La3—O17vii118.82 (11)Ti3—O3—La2xviii93.43 (14)
O15vii—La3—O17vii85.71 (12)Ti1xviii—O3—La3xviii89.43 (13)
O12—La3—O17vii169.28 (12)Ti3—O3—La3xviii90.41 (14)
O3vii—La3—O17vii62.13 (11)La2xviii—O3—La3xviii96.68 (13)
O4x—La3—O17vii61.72 (11)Ti1xviii—O3—La1xiv88.14 (13)
O10—La3—O2ix118.74 (12)Ti3—O3—La1xiv89.51 (13)
O9ix—La3—O2ix61.01 (12)La2xviii—O3—La1xiv94.41 (11)
O15vii—La3—O2ix124.80 (12)La3xviii—O3—La1xiv168.90 (15)
O12—La3—O2ix126.84 (11)Ti4—O4—Ti2xviii167.3 (2)
O3vii—La3—O2ix120.08 (11)Ti4—O4—La2xviii93.30 (15)
O4x—La3—O2ix62.37 (11)Ti2xviii—O4—La2xviii99.41 (15)
O17vii—La3—O2ix60.14 (11)Ti4—O4—La3xix90.05 (14)
O10—La3—O161.32 (12)Ti2xviii—O4—La3xix89.16 (14)
O9ix—La3—O1118.37 (12)La2xviii—O4—La3xix96.35 (13)
O15vii—La3—O1124.92 (12)Ti4—O4—La1xiv89.77 (14)
O12—La3—O1127.25 (11)Ti2xviii—O4—La1xiv88.67 (14)
O3vii—La3—O162.54 (11)La2xviii—O4—La1xiv94.28 (12)
O4x—La3—O1119.71 (11)La3xix—O4—La1xiv169.35 (16)
O17vii—La3—O160.17 (11)Ti5—O5—La5vi125.72 (18)
O2ix—La3—O176.07 (11)Ti5—O5—La4vi109.71 (16)
O10—La3—O1562.82 (11)La5vi—O5—La4vi106.52 (14)
O9ix—La3—O1562.61 (11)Ti5—O5—La598.97 (16)
O15vii—La3—O15176.71 (17)La5vi—O5—La5107.71 (13)
O12—La3—O1593.14 (12)La4vi—O5—La5106.71 (14)
O3vii—La3—O15118.10 (11)Ti6—O6—La5v129.39 (19)
O4x—La3—O15118.15 (11)Ti6—O6—La4vi111.59 (17)
O17vii—La3—O1597.58 (11)La5v—O6—La4vi108.05 (16)
O2ix—La3—O1557.40 (11)Ti5xviii—O7—La5vi103.43 (15)
O1—La3—O1557.29 (11)Ti5xviii—O7—La4vi106.73 (16)
O7ii—La4—O6ii164.16 (13)La5vi—O7—La4vi108.84 (14)
O7ii—La4—O8ii98.99 (12)Ti5xviii—O7—La5xviii101.14 (16)
O6ii—La4—O8ii71.46 (13)La5vi—O7—La5xviii110.59 (13)
O7ii—La4—O8xi97.95 (12)La4vi—O7—La5xviii123.88 (14)
O6ii—La4—O8xi70.83 (13)Ti6xviii—O8—La5v101.96 (14)
O8ii—La4—O8xi94.00 (7)Ti6xviii—O8—La4vi103.93 (15)
O7ii—La4—O5ii70.67 (12)La5v—O8—La4vi105.56 (14)
O6ii—La4—O5ii114.12 (13)Ti6xviii—O8—La4xx110.34 (17)
O8ii—La4—O5ii159.82 (12)La5v—O8—La4xx110.41 (13)
O8xi—La4—O5ii71.14 (12)La4vi—O8—La4xx122.57 (14)
O7ii—La4—O14ii113.96 (12)Ti4—O9—Ti5143.3 (2)
O6ii—La4—O14ii73.87 (13)Ti4—O9—La3xii104.01 (16)
O8ii—La4—O14ii63.85 (12)Ti5—O9—La3xii103.01 (15)
O8xi—La4—O14ii142.91 (11)Ti4—O9—La2100.83 (14)
O5ii—La4—O14ii135.91 (12)Ti5—O9—La294.45 (14)
O7ii—La4—O11ii129.31 (11)La3xii—O9—La2106.91 (14)
O6ii—La4—O11ii61.61 (12)Ti3—O10—Ti6141.5 (2)
O8ii—La4—O11ii131.69 (11)Ti3—O10—La3104.15 (15)
O8xi—La4—O11ii81.55 (12)Ti6—O10—La3103.92 (15)
O5ii—La4—O11ii61.22 (11)Ti3—O10—La2101.04 (15)
O14ii—La4—O11ii91.60 (11)Ti6—O10—La295.30 (14)
O7ii—La4—O13ii61.29 (12)La3—O10—La2107.06 (14)
O6ii—La4—O13ii133.89 (13)Ti6—O11—Ti5165.4 (2)
O8ii—La4—O13ii114.72 (12)Ti6—O11—La294.84 (14)
O8xi—La4—O13ii145.94 (11)Ti5—O11—La293.69 (14)
O5ii—La4—O13ii76.27 (12)Ti6—O11—La4vi92.15 (14)
O14ii—La4—O13ii70.08 (11)Ti5—O11—La4vi93.70 (15)
O11ii—La4—O13ii91.46 (11)La2—O11—La4vi120.66 (16)
O6i—La5—O7ii171.72 (13)Ti5ix—O12—Ti6152.0 (2)
O6i—La5—O8i73.28 (13)Ti5ix—O12—La5i95.70 (14)
O7ii—La5—O8i114.89 (13)Ti6—O12—La5i94.89 (14)
O6i—La5—O5ii99.56 (13)Ti5ix—O12—La396.31 (14)
O7ii—La5—O5ii72.17 (12)Ti6—O12—La397.02 (14)
O8i—La5—O5ii170.91 (13)La5i—O12—La3128.99 (16)
O6i—La5—O7vii69.75 (14)Ti4—O13—Ti5xviii154.5 (2)
O7ii—La5—O7vii106.16 (7)Ti4—O13—La2xviii95.14 (15)
O8i—La5—O7vii101.47 (12)Ti5xviii—O13—La2xviii85.65 (13)
O5ii—La5—O7vii70.37 (12)Ti4—O13—La4vi118.45 (18)
O6i—La5—O12v118.96 (13)Ti5xviii—O13—La4vi85.82 (12)
O7ii—La5—O12v67.17 (12)La2xviii—O13—La4vi103.49 (12)
O8i—La5—O12v68.33 (12)Ti3—O14—Ti6xviii153.9 (2)
O5ii—La5—O12v120.63 (12)Ti3—O14—La2xviii93.99 (16)
O7vii—La5—O12v161.52 (12)Ti6xviii—O14—La2xviii84.88 (13)
O6i—La5—O5113.99 (13)Ti3—O14—La4vi119.40 (18)
O7ii—La5—O569.12 (11)Ti6xviii—O14—La4vi85.94 (12)
O8i—La5—O571.71 (12)La2xviii—O14—La4vi104.28 (12)
O5ii—La5—O5107.16 (8)Ti3—O15—Ti4ix167.3 (2)
O7vii—La5—O565.00 (12)Ti3—O15—La3xviii95.81 (15)
O12v—La5—O596.73 (12)Ti4ix—O15—La3xviii95.57 (15)
O1xiii—Ti1—O1180.00 (19)Ti3—O15—La1v92.77 (14)
O1xiii—Ti1—O17viii89.67 (15)Ti4ix—O15—La1v92.28 (14)
O1—Ti1—O17viii90.33 (15)La3xviii—O15—La1v92.71 (13)
O1xiii—Ti1—O17vii90.33 (15)Ti3—O15—La384.38 (13)
O1—Ti1—O17vii89.67 (15)Ti4ix—O15—La384.58 (14)
O17viii—Ti1—O17vii180.0La3xviii—O15—La3176.71 (17)
O1xiii—Ti1—O3vii88.06 (16)La1v—O15—La384.00 (11)
O1—Ti1—O3vii91.94 (16)Ti4—O16—Ti3151.4 (2)
O17viii—Ti1—O3vii90.05 (15)Ti4—O16—La1xiv98.71 (15)
O17vii—Ti1—O3vii89.95 (15)Ti3—O16—La1xiv98.96 (14)
O1xiii—Ti1—O3viii91.94 (16)Ti4—O16—La298.73 (14)
O1—Ti1—O3viii88.06 (16)Ti3—O16—La298.10 (15)
O17viii—Ti1—O3viii89.95 (15)La1xiv—O16—La2105.27 (14)
O17vii—Ti1—O3viii90.05 (15)Ti2xx—O17—Ti1xviii163.5 (2)
O3vii—Ti1—O3viii180.00 (13)Ti2xx—O17—La1v98.38 (14)
O2—Ti2—O2xvi180.0 (3)Ti1xviii—O17—La1v98.05 (14)
O2—Ti2—O17xi89.67 (16)Ti2xx—O17—La3xviii88.35 (13)
O2xvi—Ti2—O17xi90.33 (16)Ti1xviii—O17—La3xviii88.09 (13)
O2—Ti2—O17viii90.33 (16)La1v—O17—La3xviii97.25 (13)
O2xvi—Ti2—O17viii89.67 (16)Ti2xx—O17—La2viii90.22 (13)
O17xi—Ti2—O17viii180.0 (2)Ti1xviii—O17—La2viii89.88 (13)
O2—Ti2—O4vii92.00 (17)La1v—O17—La2viii94.93 (12)
O2xvi—Ti2—O4vii88.00 (17)La3xviii—O17—La2viii167.82 (16)
O17xi—Ti2—O4vii89.97 (15)
Symmetry codes: (i) x+1, y1/2, z+1/2; (ii) x, y1/2, z+1/2; (iii) x, y+1/2, z+1/2; (iv) x+1, y3/2, z+1/2; (v) x+1, y+1/2, z+1/2; (vi) x, y+1/2, z+1/2; (vii) x, y1, z; (viii) x+1, y+1, z; (ix) x+1, y, z; (x) x+1, y1, z; (xi) x1, y1, z; (xii) x1, y, z; (xiii) x+1, y, z; (xiv) x, y+1/2, z1/2; (xv) x, y1/2, z1/2; (xvi) x, y, z; (xvii) x, y+1, z; (xviii) x, y+1, z; (xix) x1, y+1, z; (xx) x+1, y+1, z; (xxi) x+1, y+3/2, z+1/2.

Experimental details

Crystal data
Chemical formulaLa5Ti5O17
Mr1205.90
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)7.8580 (11), 5.5281 (9), 31.449 (5)
β (°) 97.166 (16)
V3)1355.5 (4)
Z4
Radiation typeMo Kα
µ (mm1)18.25
Crystal size (mm)0.10 × 0.08 × 0.01
Data collection
DiffractometerEnraf-Nonius MACH3
diffractometer
Absorption correctionψ scan
(Herrendorf, 1992)
Tmin, Tmax0.31, 0.89
No. of measured, independent and
observed [I > 2σ(I)] reflections
21243, 6456, 5164
Rint0.053
(sin θ/λ)max1)0.845
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.082, 1.13
No. of reflections6456
No. of parameters248
w = 1/[σ2(Fo2) + (0.0238P)2 + 11.7499P]
where P = (Fo2 + 2Fc2)/3
Δρmax, Δρmin (e Å3)3.22, 3.16

Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, HELENA (Spek, 1996), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), SHELXL97.

Mean Ti-O and La-O distances (Å) and O-Ti-O angles (°). Mean La-O distances are given for coordination numbers of 12 (La1-La3), 10 (La4) and [7 + 3] (La5). top
<Ti1-O>1.983 (26)
<Ti2-O>1.979 (22)
<Ti3-O>1.989 (110)
<Ti4-O>1.985 (105)
<Ti5-O>1.977 (141)
<Ti6-O>1.986 (161)
<La1-O>2.754 (247)
<La2-O>2.735 (287)
<La3-O>2.759 (277)
<La4-O>2.697 (244)
<La5-O>2.784 (520)
<O-Ti1-O>90.00 (119)
<O-Ti2-O>90.00 (122)
<O-Ti3-O>89.66 (677)
<O-Ti4-O>89.68 (666)
<O-Ti5-O>89.77 (647)
<O-Ti6-O>89.71 (673)
 

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