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A new quaternary compound in the Ca-Eu-Sn-O system, namely calcium europium tin hepta­oxide, Ca1.5Eu3Sn0.5O7, was prepared by solid-state reaction at 2073 K. All atoms in the structure are on 4i special positions (on mirrors) in space group C2/m. Ca/Eu sites are situated within two O octa­hedra and within two sevenfold coordination sites surrounded by O-capped trigonal prisms. A Ca/Eu/Sn site is coordinated by five O atoms. The structural formula can be represented as (Ca0.28Eu0.72)(Ca0.16Eu0.84)(Ca0.46Eu0.54)(Ca0.28Eu0.72)(Ca0.32Eu0.18Sn0.50)O7. The crystal structure is a new type and is related to the structure of B-form Eu2O3.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270106039916/fa3035sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270106039916/fa3035Isup2.hkl
Contains datablock I

Comment top

Recently, a new quaternary oxide, Ca0.8Y2.4Sn0.8O6, isostructural with Mg3TeO6 and a member of the Ca–Y–Sn–O system, was prepared by solid-state reaction (Kaminaga et al., 2006). In an attempt to substitute Eu atoms for all Y atoms in the compound, a mixture of the compound with the Mg3TeO6-type structure and CaSnO3 with a perovskite-type structure was prepared at 1673 K. In order to make single crystals, we heated the sample to 2073 K and in fact obtained the title new quaternary compound with a new structure in the Ca–Eu–Sn–O system, and present its structure here.

A Ca:Eu:Sn molar ratio of 3:6:1 was measured for the single crystals obtained, using an energy-dispersive X-ray (EDX) analyser on a scanning electron microscope. The proportions of Eu and Sn in the crystals were lower than those in the starting materials (Ca:Eu:Sn = 1:3:1).

All metal (M) and O atoms are located on mirrors (4i special positions) with y = 0 and 1/2. After obtaining a starting model using SIR2004 (Burla et al. 2005), Eu atoms were tentatively placed at all M sites for the first step and their positions were refined. The bond-valence sums for the M sites, calculated with the bond lengths [Text missing?] and the bond-valence parameter of EuIII—OII = 2.076 (Brese & O'Keeffe, 1991), were 2.771, 2.943, 2.694, 2.947 and 3.785, respectively. Based on this information, we set four mixed sites of Ca and Eu atoms (Ca/Eu), where the bond-valence sums were below 3, and a Ca/Eu/Sn site with the bond valence above 3. In accordance with the composition analysed by EDX, the occupancy parameter of Sn at the Ca/Eu/Sn site was fixed at 0.5. The occupancy parameters of the Ca and Eu atoms at the sites of Ca1/Eu1, Ca2/Eu2, Ca3/Eu3, Ca4/Eu4 and Ca5/Eu5/Sn5 were refined to 0.278 (3)/0.722 (3), 0.165 (3)/0.835 (3), 0.458 (3)/0.542 (3), 0.281 (3)/0.719 (3) and 0.32 (19)/0.18 (5), respectively. The overall Ca:Eu:Sn molar ratio, calculated with these values, was in good agreement with the ratio from the EDX analysis (Ca:Eu:Sn = 3:6:1).

Fig. 1 shows the atomic arrangement around the M sites with Ca1/Eu1- and Ca2/Eu2-centred oxygen trigonal prisms. Ca1/Eu1 and Ca2/Eu2 sites are surrounded by six nearest O atoms which form trigonal prisms. The M—O bond lengths in the Ca1/Eu1- and Ca2/Eu2-centred prisms are 2.272 (6)–2.528 (4) Å and 2.288 (3)–2.488 (4) Å, respectively. The second-nearest neighbour O atoms, capping the widest rectangular plane of each trigonal prism, are located 2.606 (7) Å from Ca1/Eu1 and 2.716 (5) Å from Ca2/Eu2. Consequently, the corresponding metal atom sites are best described as seven-coordinated. The O atoms surrounding the Ca3/Eu3 and Ca4/Eu4 sites form distorted octahedra. The M—O bond lengths are 2.213 (5)–2.541 (4) Å (Ca3/Eu3—O) and 2.250 (3)–2.580 (4) Å (Ca4/Eu4—O). Second-nearest neighbour O atoms are located at distances of 3.204 (7) Å (Ca3/Eu3—O1) and 3.311 (9) Å (Ca4/Eu4—O6) Å. The Ca5/Eu5/Sn5 site is coordinated by five O atoms with bond lengths from 2.118 (3) to 2.386 (9) Å. The second-nearest neighbour O atom is 3.236 (5) Å from the Ca5/Eu5/Sn5 site.

The arrangement of M atoms around O atoms is shown in Fig. 2. Atoms O4, O5, O6 and O7 are surrounded by four M atoms, atom O1 by five M atoms, and atoms O2 and O3 by six M atoms. The equivalent isotropic displacement parameter of atom O6 is almost twice those of the other O atoms. This may result from the difference in the coordination environment around O6 compared with the others. Each O atom except O6 is located inside an M polyhedron, while atom O6vi lies in a plane formed by Ca1/Eu1xii, Ca1/Eu1xiii and Ca5/Eu5/Sn5vi [symmetry codes: (vi) ?; (xii) ?; (xiii) ? Please complete]. These three sites are parts of a distorted tetrahedron which is completed by Ca5/Eu5/Sn5xv [symmetry code: (xv) ? Please complete]. The direction of the ellipsoid long axis is toward the Ca4/Eu4vi and Ca5/Eu5/Sn5xv sites, with distances of 3.311 (9) and 2.386 (9) Å, respectively.

We could not find any isotypic compound in the inorganic crystal structure database (ICSD, 2005). However, the crystal structure of Ca1.5Eu3Sn0.5O7 can be related to the structure of the B form of Eu2O3. This form is a mid-temperature monoclinic phase which is stable from 1423 to 2273 K, between the high-temperature A form hexagonal phase and the low-temperature C form cubic phase (Yakel, 1979). The space group of the B form of Eu2O3 is the same (C2/m) as that of Ca1.5Eu3Sn0.5O7. The refined unit-cell parameters of B-form Eu2O3 are a = 14.1105 (2) Å, b = 3.6021 (1) Å, c = 8.8080 (2) Å and β = 100.037 (1)°, and the unit-cell volume is 440.84 (3) Å3. In the structure of B-form Eu2O3, there are three Eu sites and five O sites, all of which are also on 4i special positions with y = 0 and 1/2. The b axis lengths of B-form Eu2O3 and Ca1.5Eu3Sn0.5O7 [3.6294 (2) Å] are similar. The coordination environments of Eu1 and Eu2 are similar to those of Ca1/Eu1 and Ca2/Eu2 in Ca1.5Eu3Sn0.5O7. The Eu1—O bond lengths are 2.290 (2)–2.537 (2) Å (prism) and 2.656 (4) Å (cap), and the Eu2—O bond lengths are 2.288 (2)–2.462 (2) Å (prism) and 2.7394 (2) Å(cap). As with the Ca3/Eu3 and Ca4/Eu4 sites of the present structure of Ca1.5Eu3Sn0.5O7, in B-form Eu2O3 the Eu3 atoms are in a distorted O octahedron, with M—O bond lengths ranging from 2.239 (2) to 2.544 (1) Å. The second-nearest neighbour O atom is 3.133 (4) Å from Eu3.

The extended structure of Ca1.5Eu3Sn0.5O7 is illustrated in Fig. 3(a) with Ca1/Eu1- and Ca2/Eu2-centred O6 trigonal prisms. The structure of B-form Eu2O3 is shown in Fig. 3(b) with Eu1- and Eu2-centred O6 trigonal prisms. As shown in Fig. 4, pairs of Ca1/Eu1-centred prisms in Ca1.5Eu3Sn0.5O7, sharing O4—O4(symmetry code?) edges lying in the plane (501), stack parallel to the b-axis direction by sharing O3—O6 edges. Pairs of Ca2/Eu2-centred prisms, which share O7—O7(symmetry code?) edges lying in the (101) plane, stack parallel to the b-axis direction by sharing O3—O7 edges. Ca1/Eu1- and Ca2/Eu2-centred trigonal prism pairs share O3—O3(symmetry code?) edges and form trigonal prism layers in the (201) plane. Ca3/Eu3, Ca4/Eu4 and Ca5/Eu5/Sn5 atoms are located between the trigonal prism layers (Fig. 3a). A similar arrangement of prism pairs is seen in the structure of B-form Eu2O3, where the layers of Eu1- and Eu2-centred prism pairs share vertices and form tunnels parallel to the b-axis direction. Eu3 atoms are in sevenfold coordination sites in the tunnels.

Experimental top

The starting materials were powders of Eu2O3 (99.99% purity; Rare Metallic), CaCO3 (99.99% purity; Rare Metallic) and SnO2 (99.9% purity; Sigma–Aldrich). Y2O3 and SnO2 powders were heated at 1273 K for 6 h before weighing. The powders were weighed and mixed in a Ca:Eu:Sn molar ratio of 1:3:1. The mixture was pressed into a pellet at 50 MPa and placed on a platinum–rhodium plate. The polycrystalline sample of Ca1.5Eu3Sn0.5O7 was prepared by reaction sintering at 2073 K with an electric furnace in air. After heating at this temperature for 12 h, the sample was cooled to room temperature in the furnace. The growth of grains was observed in the sample. A colourless translucent single-crystal platelet was selected from the grains. The compositions of Ca, Eu and Sn in the single-crystal were measured using a scanning electron microscope (SEM, Hitachi, S3000500N) with an energy dispersive X-ray spectrometer (EDX, HORIBA, EMAX-500).

Refinement top

The highest peak (1.517 Å−3) and deepest hole (−1.415 Å−3) in the Fo - Fc map were observed at (0.1437, 0.0000, 0.0666), 0.87 Å from O1, and at (0.3523, 0.0000, 0.4679), 0.63 Å from Eu4, respectively.

Computing details top

Data collection: PROCESS-AUTO (Rigaku/MSC, 2005); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2005); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ATOMS (Dowty, 1999); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The O-atom coordination around five M sites in the structure of Ca1.5Eu3Sn0.5O7, showing Ca1/Eu1- and Ca2/Eu2-centred O6 trigonal prisms. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes as in Table 1; additionally: (x) −x + 1/2, −y + 1/2, z; (xi) x + 1/2, y − 1/2 z + 1.]
[Figure 2] Fig. 2. The M-atom coordination around O sites. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes as in Table 1; additionally: (xii) x + 1/2, y − 1/2, z; (xiii) x + 1/2, y + 1/2, z; (xiv) −x + 1/2, −y + 1/2, −z; (xv) Text missing?; (xii) x + 1/2, y − 1/2, z + 1.]
[Figure 3] Fig. 3. (a) The extended structure of Ca1.5Eu3Sn0.5O7, illustrated with Ca1/Eu1- and Ca2/Eu2-centred O6 trigonal prisms. (b) The structure of B-form Eu2O3, illustrated with Eu1- and Eu2-centred O6 trigonal prisms.
[Figure 4] Fig. 4. The arrangement of Ca1/Eu1-centred and Ca2/Eu2-centred O6 trigonal prisms in Ca1.5Eu3Sn0.5O7.
calcium europium tin heptaoxide top
Crystal data top
Ca1.5Eu3O7Sn0.5F(000) = 1200
Mr = 687.35Dx = 6.384 Mg m3
Monoclinic, C2/mMo Kα radiation, λ = 0.71069 Å
Hall symbol: -C 2yCell parameters from 1000 reflections
a = 22.8628 (11) Åθ = 3.1–27.5°
b = 3.6294 (2) ŵ = 28.75 mm1
c = 9.0610 (4) ÅT = 296 K
β = 107.9150 (14)°Platelet, colourless
V = 715.41 (6) Å30.07 × 0.05 × 0.03 mm
Z = 4
Data collection top
Rigaku R-AXIS RAPID
diffractometer
945 independent reflections
Radiation source: fine-focus sealed tube858 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.059
Detector resolution: 10.00 pixels mm-1θmax = 27.4°, θmin = 3.4°
ω scansh = 2728
Absorption correction: numerical
(NUMABS; Higashi, 1999)
k = 44
Tmin = 0.276, Tmax = 0.719l = 1111
3610 measured reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullPrimary atom site location: structure-invariant direct methods
R[F2 > 2σ(F2)] = 0.026Secondary atom site location: difference Fourier map
wR(F2) = 0.061 w = 1/[σ2(Fo2) + 4.2873P]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max = 0.001
945 reflectionsΔρmax = 1.52 e Å3
73 parametersΔρmin = 1.42 e Å3
Crystal data top
Ca1.5Eu3O7Sn0.5V = 715.41 (6) Å3
Mr = 687.35Z = 4
Monoclinic, C2/mMo Kα radiation
a = 22.8628 (11) ŵ = 28.75 mm1
b = 3.6294 (2) ÅT = 296 K
c = 9.0610 (4) Å0.07 × 0.05 × 0.03 mm
β = 107.9150 (14)°
Data collection top
Rigaku R-AXIS RAPID
diffractometer
945 independent reflections
Absorption correction: numerical
(NUMABS; Higashi, 1999)
858 reflections with I > 2σ(I)
Tmin = 0.276, Tmax = 0.719Rint = 0.059
3610 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.02673 parameters
wR(F2) = 0.0610 restraints
S = 1.06Δρmax = 1.52 e Å3
945 reflectionsΔρmin = 1.42 e Å3
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*/UeqOcc. (<1)
Ca10.03264 (2)0.00000.71401 (5)0.01056 (14)0.28
Eu10.03264 (2)0.00000.71401 (5)0.01056 (14)0.72
Ca20.186221 (18)0.00000.86957 (4)0.00880 (14)0.16
Eu20.186221 (18)0.00000.86957 (4)0.00880 (14)0.84
Ca30.21609 (3)0.00000.32017 (6)0.01153 (15)0.46
Eu30.21609 (3)0.00000.32017 (6)0.01153 (15)0.54
Ca40.11926 (2)0.50000.50076 (5)0.01370 (15)0.28
Eu40.11926 (2)0.50000.50076 (5)0.01370 (15)0.72
Ca50.07728 (2)0.50000.06738 (6)0.01160 (16)0.32
Eu50.07728 (2)0.50000.06738 (6)0.01160 (16)0.18
Sn50.07728 (2)0.50000.06738 (6)0.01160 (16)0.50
O10.1080 (3)0.00000.9960 (8)0.0373 (16)
O20.2032 (2)0.00000.5857 (6)0.0231 (14)
O30.1127 (3)0.50000.7480 (6)0.0218 (12)
O40.0589 (3)0.00000.4777 (6)0.0257 (13)
O50.1521 (3)0.50000.2891 (6)0.0200 (12)
O60.0042 (4)0.50000.1722 (9)0.050 (2)
O70.2516 (3)0.00000.1189 (5)0.0168 (11)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ca10.0109 (3)0.0113 (3)0.0094 (2)0.0000.00318 (16)0.000
Eu10.0109 (3)0.0113 (3)0.0094 (2)0.0000.00318 (16)0.000
Ca20.0080 (2)0.0077 (2)0.0092 (2)0.0000.00038 (15)0.000
Eu20.0080 (2)0.0077 (2)0.0092 (2)0.0000.00038 (15)0.000
Ca30.0133 (3)0.0087 (3)0.0160 (3)0.0000.0095 (2)0.000
Eu30.0133 (3)0.0087 (3)0.0160 (3)0.0000.0095 (2)0.000
Ca40.0191 (3)0.0107 (3)0.0154 (3)0.0000.01123 (19)0.000
Eu40.0191 (3)0.0107 (3)0.0154 (3)0.0000.01123 (19)0.000
Ca50.0098 (3)0.0125 (3)0.0107 (3)0.0000.0005 (2)0.000
Eu50.0098 (3)0.0125 (3)0.0107 (3)0.0000.0005 (2)0.000
Sn50.0098 (3)0.0125 (3)0.0107 (3)0.0000.0005 (2)0.000
O10.034 (4)0.041 (5)0.044 (4)0.0000.023 (3)0.000
O20.023 (3)0.024 (4)0.022 (3)0.0000.007 (2)0.000
O30.023 (3)0.019 (3)0.019 (3)0.0000.000 (2)0.000
O40.015 (3)0.037 (4)0.024 (3)0.0000.004 (2)0.000
O50.022 (3)0.019 (3)0.020 (3)0.0000.007 (2)0.000
O60.060 (5)0.032 (5)0.073 (5)0.0000.042 (4)0.000
O70.020 (3)0.017 (3)0.011 (2)0.0000.003 (2)0.000
Geometric parameters (Å, º) top
Ca1/Eu1—O4i2.272 (6)Ca3/Eu3—O22.513 (5)
Ca1/Eu1—O6ii2.367 (4)Ca3/Eu3—O2iii2.541 (4)
Ca1/Eu1—O42.395 (5)Ca4/Eu4—O42.250 (3)
Ca1/Eu1—O32.528 (4)Ca4/Eu4—O52.264 (5)
Ca1/Eu1—O12.606 (7)Ca4/Eu4—O32.291 (5)
Ca2/Eu2—O7iii2.288 (3)Ca4/Eu4—O22.580 (4)
Ca2/Eu2—O7iv2.293 (5)Ca4/Eu4—O63.311 (9)
Ca2/Eu2—O12.402 (6)Ca5/Eu5/Sn5—O1v2.118 (3)
Ca2/Eu2—O32.488 (4)Ca5/Eu5/Sn5—O62.160 (7)
Ca2/Eu2—O22.716 (5)Ca5/Eu5/Sn5—O52.202 (5)
Ca3/Eu3—O72.213 (5)Ca5/Eu5/Sn5—O6vi2.386 (9)
Ca3/Eu3—O52.293 (4)
O3—Ca1/Eu1—O169.19 (14)O4—Ca4/Eu4—O2ix166.72 (16)
O4—Ca1/Eu1—O374.78 (15)O1x—Ca5/Eu5/Sn5—O6vi87.8 (2)
O6ii—Ca1/Eu1—O374.82 (18)O6—Ca5/Eu5/Sn5—O6vi84.6 (3)
O4i—Ca1/Eu1—O475.0 (2)O1x—Ca5/Eu5/Sn5—O592.4 (2)
O6i—Ca1/Eu1—O177.8 (2)O6—Ca5/Eu5/Sn5—O595.0 (3)
O4i—Ca1/Eu1—O6ii88.0 (2)O1v—Ca5/Eu5/Sn5—O1x117.9 (3)
O3—Ca1/Eu1—O3vii91.73 (19)O1x—Ca5/Eu5/Sn5—O6120.55 (15)
O6ii—Ca1/Eu1—O6i100.1 (3)O5—Ca5/Eu5/Sn5—O6vi179.7 (2)
O4i—Ca1/Eu1—O3123.74 (13)Ca1/Eu1ii—O6—Ca4/Eu484.2 (2)
O4—Ca1/Eu1—O1127.18 (18)Ca1/Eu1ix—O3—Ca1/Eu191.73 (19)
O6ii—Ca1/Eu1—O4127.62 (15)Ca1/Eu1ii—O6—Ca5/Eu5/Sn5vi96.5 (3)
O6i—Ca1/Eu1—O3147.0 (2)Ca1/Eu1i—O4—Ca1/Eu1105.0 (2)
O4i—Ca1/Eu1—O1157.8 (2)Ca1/Eu1ii—O6—Ca1/Eu1i100.1 (3)
O1—Ca2/Eu2—O373.18 (16)Ca2/Eu2—O3—Ca1/Eu184.01 (4)
O7viii—Ca2/Eu2—O7iv75.36 (14)Ca2/Eu2—O1—Ca1/Eu184.11 (19)
O7viii—Ca2/Eu2—O376.55 (15)Ca2/Eu2ix—O3—Ca2/Eu293.65 (18)
O7viii—Ca2/Eu2—O277.04 (14)Ca2/Eu2iii—O7—Ca2/Eu2xi104.64 (14)
O3—Ca2/Eu2—O281.64 (14)Ca2/Eu2viii—O7—Ca2/Eu2iii105.0 (2)
O7iv—Ca2/Eu2—O183.4 (2)Ca2/Eu2—O3—Ca1/Eu1ix160.5 (2)
O3vii—Ca2/Eu2—O393.65 (19)Ca3/Eu3viii—O2—Ca4/Eu489.689 (14)
O7viii—Ca2/Eu2—O7iii105.0 (2)Ca3/Eu3viii—O2—Ca2/Eu289.01 (13)
O7viii—Ca2/Eu2—O1121.43 (13)Ca3/Eu3—O2—Ca4/Eu490.57 (14)
O7iv—Ca2/Eu2—O3125.65 (11)Ca3/Eu3viii—O2—Ca3/Eu3iii91.13 (17)
O7iv—Ca2/Eu2—O2133.87 (17)Ca3/Eu3—O2—Ca3/Eu3viii91.96 (14)
O1—Ca2/Eu2—O2142.7 (2)Ca3/Eu3—O7—Ca2/Eu2viii110.03 (14)
O7iii—Ca2/Eu2—O3157.57 (17)Ca3/Eu3ix—O5—Ca3/Eu3104.6 (2)
O5—Ca3/Eu3—O281.90 (15)Ca3/Eu3—O7—Ca2/Eu2xi121.3 (2)
O7—Ca3/Eu3—O2viii82.18 (15)Ca3/Eu3iii—O2—Ca4/Eu4177.3 (2)
O2—Ca3/Eu3—O2viii88.04 (14)Ca3/Eu3—O2—Ca2/Eu2178.6 (2)
O2viii—Ca3/Eu3—O2iii91.13 (17)Ca4/Eu4—O2—Ca2/Eu288.44 (14)
O5vii—Ca3/Eu3—O2iii81.15 (14)Ca4/Eu4vii—O2—Ca4/Eu489.38 (17)
O7—Ca3/Eu3—O5106.30 (15)Ca4/Eu4—O3—Ca1/Eu198.25 (15)
O5vii—Ca3/Eu3—O5104.6 (2)Ca4/Eu4—O3—Ca2/Eu2101.22 (17)
O7—Ca3/Eu3—O2165.99 (18)Ca4/Eu4vii—O4—Ca1/Eu1103.44 (16)
O5—Ca3/Eu3—O2iii167.49 (17)Ca4/Eu4—O5—Ca3/Eu3105.15 (16)
O4—Ca4/Eu4—O667.79 (14)Ca4/Eu4—O4—Ca4/Eu4vii107.5 (2)
O5—Ca4/Eu4—O667.49 (18)Ca4/Eu4—O4—Ca1/Eu1i117.72 (15)
O4—Ca4/Eu4—O280.72 (14)Ca5/Eu5/Sn5—O6—Ca4/Eu483.5 (3)
O5—Ca4/Eu4—O280.95 (15)Ca5/Eu5/Sn5—O6—Ca5/Eu5/Sn5vi95.4 (3)
O4—Ca4/Eu4—O382.42 (16)Ca5/Eu5/Sn5iv—O1—Ca1/Eu196.8 (2)
O3—Ca4/Eu4—O288.54 (15)Ca5/Eu5/Sn5—O5—Ca4/Eu4113.9 (2)
O2ix—Ca4/Eu4—O289.38 (17)Ca5/Eu5/Sn5—O5—Ca3/Eu3113.52 (15)
O4—Ca4/Eu4—O5105.97 (16)Ca5/Eu5/Sn5xii—O1—Ca5/Eu5/Sn5iv117.9 (3)
O4—Ca4/Eu4—O4ix107.5 (2)Ca5/Eu5/Sn5iv—O1—Ca2/Eu2120.75 (14)
O2—Ca4/Eu4—O6125.47 (11)Ca5/Eu5/Sn5—O6—Ca1/Eu1ii128.21 (16)
O3—Ca4/Eu4—O6127.35 (18)Ca5/Eu5/Sn5vi—O6—Ca4/Eu4178.9 (3)
O5—Ca4/Eu4—O3165.16 (19)
Symmetry codes: (i) x, y, z+1; (ii) x, y+1, z+1; (iii) x+1/2, y1/2, z+1; (iv) x, y, z+1; (v) x, y, z1; (vi) x, y+1, z; (vii) x, y1, z; (viii) x+1/2, y+1/2, z+1; (ix) x, y+1, z; (x) x, y+1, z1; (xi) x, y, z1; (xii) x, y1, z+1.

Experimental details

Crystal data
Chemical formulaCa1.5Eu3O7Sn0.5
Mr687.35
Crystal system, space groupMonoclinic, C2/m
Temperature (K)296
a, b, c (Å)22.8628 (11), 3.6294 (2), 9.0610 (4)
β (°) 107.9150 (14)
V3)715.41 (6)
Z4
Radiation typeMo Kα
µ (mm1)28.75
Crystal size (mm)0.07 × 0.05 × 0.03
Data collection
DiffractometerRigaku R-AXIS RAPID
diffractometer
Absorption correctionNumerical
(NUMABS; Higashi, 1999)
Tmin, Tmax0.276, 0.719
No. of measured, independent and
observed [I > 2σ(I)] reflections
3610, 945, 858
Rint0.059
(sin θ/λ)max1)0.648
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.026, 0.061, 1.06
No. of reflections945
No. of parameters73
Δρmax, Δρmin (e Å3)1.52, 1.42

Computer programs: PROCESS-AUTO (Rigaku/MSC, 2005), PROCESS-AUTO, CrystalStructure (Rigaku/MSC, 2005), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 1997), ATOMS (Dowty, 1999), SHELXL97.

Selected bond lengths (Å) top
Ca1/Eu1—O4i2.272 (6)Ca3/Eu3—O22.513 (5)
Ca1/Eu1—O6ii2.367 (4)Ca3/Eu3—O2iii2.541 (4)
Ca1/Eu1—O42.395 (5)Ca4/Eu4—O42.250 (3)
Ca1/Eu1—O32.528 (4)Ca4/Eu4—O52.264 (5)
Ca1/Eu1—O12.606 (7)Ca4/Eu4—O32.291 (5)
Ca2/Eu2—O7iii2.288 (3)Ca4/Eu4—O22.580 (4)
Ca2/Eu2—O7iv2.293 (5)Ca4/Eu4—O63.311 (9)
Ca2/Eu2—O12.402 (6)Ca5/Eu5/Sn5—O1v2.118 (3)
Ca2/Eu2—O32.488 (4)Ca5/Eu5/Sn5—O62.160 (7)
Ca2/Eu2—O22.716 (5)Ca5/Eu5/Sn5—O52.202 (5)
Ca3/Eu3—O72.213 (5)Ca5/Eu5/Sn5—O6vi2.386 (9)
Ca3/Eu3—O52.293 (4)
Symmetry codes: (i) x, y, z+1; (ii) x, y+1, z+1; (iii) x+1/2, y1/2, z+1; (iv) x, y, z+1; (v) x, y, z1; (vi) x, y+1, z.
 

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