Lead germanium oxide

inorganic papers

Acta Cryst.(2006). E62, i135–i137 doi:10.1107/S1600536806017697 Xuet al. _GeO

3Pb

i135

Structure Reports Online

ISSN 1600-5368

Lead germanium oxide

Yan Xu,a* Li-Ying Cheng,a

Guang-Peng Zhouband Yan-Li

Wanga

a_{College of Chemistry and Chemical}

Engineering, Liaoning Normal University, 116029, Dalian, People’s Republic of China, andb_{Institute of Chemistry for Functionalized} Materials, College of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian, 116029, People’s Republic of China

Correspondence e-mail: [email protected]

Key indicators

Single-crystal X-ray study

T= 293 K

Mean(Ge–O) = 0.019 A˚

Rfactor = 0.050

wRfactor = 0.164

Data-to-parameter ratio = 13.4

For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.

Received 26 April 2006 Accepted 12 May 2006

#2006 International Union of Crystallography All rights reserved

The crystal structure of the title compound, PbGeO3, shows a

three-dimensional framework assembled by Pb6 and Ge6

structural building units. The Pb atom is coordinated by five O atoms in square-pyramidal coordination, while the Ge atom is tetrahedrally coordinated by four O atoms.

Comment

Over the past decades, the synthesis of new open-framework materials with either pure tetrahedral or mixed polyhedral microporous arrangements have received great attention due to their functional applications in catalysis, adsorption, ion-exchange and radioactive waste remediation. Not only aluminium and silicon, but also boron, gallium, phosphorus, germanium and transition metals have been choosen as open-framework building elements to synthesize new three-dimensional materials (Liet al., 1998; Linet al., 2003; Ple´vertet al., 2001; Xu, Fan, Chinoet al., 2004; Xu, Fan, Elangovanet al., 2004). Compared with silicon, germanium not only adopts

longer metal–oxygen distances (about 1.76 A˚ for Ge—O,

1.61 A˚ for Si—O), but also exhibits three types of coord-ination polyhedra,viz. GeO4, GeO5and GeO6. Therefore, the flexibility of the polyhedral model for germanium allows the formation of various open frameworks. In particular, germa-nium shows a great ability to form rings containing three metal atoms. Some germanates with such rings have already been reported (Buet al., 1998; Liet al., 2000; Xu, Ogura & Okubo, 2004).

In this work, we have designed and synthesized the title compound, which features a three-dimensional framework derived from Pb6 and Ge6 structural building units. Both building units are connected by a new type of Ge2Pb ring. The molecular structure of the title compound is shown in Fig. 1. The asymmetric unit of PbGeO3 contains one formula unit. The O atoms in the open framework can be divided into three groups,viz.O2b, O3band O4b, where O2brepresents an O atom

Figure 1

connected to two Ge atoms, O3bis connected to one Ge and

two Pb atoms, and O4bto one Ge and three Pb atoms. The Pb

atom is five-coordinated by two O3band three O4batoms.

As shown in Fig.2, six PbO5square pyramids form a Pb6ring structure by sharing corners, and six corner-sharing GeO4 tetrahedra form a Ge6ring (Fig. 3). These two building units are connected by Ge2Pb rings (two GeO4 and one PbO5), yielding a three-dimensional open framework with channels along the [111] direction (the rhombohedral symmetry axis) (Fig. 4).

The Pb—O and Ge—O bond lengths (Table 1) are in agreement with those found in previously reported lead and germanium compounds (Buet al., 1998; Shiet al., 2002). The

shortest Pb Pb distance in the Pb6 building unit is

3.6910 (8) A˚ , while Pb Pb Pb is 118.066 (12)_{, which is} very close to 120_.

Experimental

The title compound was hydrothermally synthesized from a mixture of GeO2, H3BO3, Pb(OAc)23H2O, diethylenetriamine, HF, pyridine

and H2O in the molar ratio 2:1:2:4:4:74:180. In a typical synthesis,

GeO2(0.01 g) and H3BO3(0.03 g) were dissolved in a mixed solvent

of pyridine (2.84 g) and water (1.60 g), followed by the addition of

Pb(OAc)23H2O (0.36 g) and diethylenetriamine (0.23 g) with

constant stirring. Finally, hydrofluoric acid (0.1 ml, 40 wt %) was added to the above mixture. The mixture was kept in a 25 ml Teflon-lined steel autoclave at 443 K for 7 d. The autoclave was slowly cooled to room temperature, and then the product was filtered off, washed with distilled water and acetone, and dried at room temperature. Colourless block-shaped crystals were obtained. We have attempted to find crystals of better quality and to optimize the synthesis, but no better single crystals could be obtained.

Crystal data

GeO3Pb Mr= 327.78 Rhombohedral,R3

a= 9.3282 (2) A˚

= 113.4560 (2)

V= 512.43 (2) A˚3 Z= 6

Dx= 6.373 Mg m3 MoKradiation

= 57.82 mm1

T= 293 (2) K Block, colourless 0.040.030.03 mm

Data collection

Bruker APEX2 CCD diffractometer

!scans

Absorption correction: multi-scan (SADABS; Sheldrick, 2003)

Tmin= 0.206,Tmax= 0.276

(expected range = 0.132–0.176)

2654 measured reflections 628 independent reflections 553 reflections withI> 2(I)

Rint= 0.047

max= 25.5

Refinement

Refinement onF2 R[F2_{> 2(F}2_{)] = 0.050} wR(F2_{) = 0.164} S= 1.21 628 reflections 47 parameters

w= 1/[2_(F

o2) + (0.1096P)2]

whereP= (Fo2+ 2Fc2)/3

(/)max= 0.001 max= 4.40 e A˚

3 min=3.49 e A˚

3

Extinction correction:SHELXL97

Extinction coefficient: 0.0022 (8)

Table 1

Selected bond lengths (A˚ ).

Pb1—O1i

2.270 (14) Pb1—O3ii

2.416 (15) Pb1—O1 2.458 (14) Pb1—O3 2.551 (16) Pb1—O3iii

2.590 (15)

Ge1—O1 1.723 (14) Ge1—O3iv

1.725 (15) Ge1—O2 1.779 (15) Ge1—O2v

1.781 (15)

Symmetry codes: (i) z;x1;y; (ii) yþ1;z;xþ1; (iii) xþ1;y;z; (iv) xþ2;yþ1;zþ1; (v)zþ2;xþ2;yþ1.

inorganic papers

i136

3Pb Acta Cryst.(2006). E62, i135–i137

Figure 4

The three-dimensional open framework with channels, viewed along [111].

Figure 3

The structure of the Ge6building unit.

Figure 2

The highest peak in the difference map is located 1.08 (2) A˚ from Pb1, while the deepest hole is 1.13 (3) A˚ from Pb1.

Data collection:APEX2(Bruker, 2005); cell refinement:SAINT

(Bruker, 2002); data reduction: SAINT; program(s) used to solve structure:SHELXS97(Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics:

SHELXTL(Sheldrick, 1997b); software used to prepare material for publication:SHELXTL.

This work was supported by the Education Office Found-ation of Liaoning Province (grant No. 05L220).

References

Bruker (2002).SAINT. Version 6.36a. Bruker AXS Inc., Madison, Wisconsin, USA.

Bruker (2005).APEX2. Version 1.27. Bruker AXS Inc., Madison, Wisconson, USA.

Bu, X., Feng, P. & Stucky, G. D. (1998). J. Am. Chem. Soc. 120, 11204– 11205.

Li, H., Eddaoudi, M., Ple´vert, J., O’Keeffe, M. & Yaghi, O. M. (2000).J. Am. Chem. Soc.122, 12409–12410.

Li, H., Eddaoudi, M., Richardson, D. A. & Yaghi, O. M. (1998).J. Am. Chem. Soc.120, 8567–8568.

Lin, Z., Zhang, J. & Yang, G. (2003).Inorg. Chem.42, 1797–1799.

Ple´vert, J., Gentz, T. M., Laine, A., Li, H., Young, V. G., Yaghi, O. M. & O’Keeffe, M. (2001).J. Am. Chem. Soc.123, 12706–12707.

Sheldrick, G. M. (1997a). SHELXS97 and SHELXL97. University of Go¨ttingen, Germany.

Sheldrick, G. M. (1997b).SHELXTLVersion 5.10. Bruker AXS Inc., Madison, Wisconsin, USA.

Sheldrick, G. M. (2003).SADABS. University of Go¨ttingen, Germany. Shi, Y., Li, L., Li, Y., Xu, Y., Chen, X., Xue, Z. & You, X. (2002).Inorg. Chem.

Commun.5, 1090–1094.

Xu, Y., Fan, W., Chino, N., Uehara, K., Hikichi, S., Mizuno, N., Ogura, M. & Okubo, T. (2004).Chem. Lett.33, 74–75.

Xu, Y., Fan, W., Elangovan, S. P., Ogura, M. & Okubo, T. (2004).Eur. J. Inorg. Chem.pp. 4547–4549.

Xu, Y., Ogura, M. & Okubo, T. (2004).Microporous Mesoporous Mater.70, 1– 6.

inorganic papers

Acta Cryst.(2006). E62, i135–i137 Xuet al. _GeO

supporting information

sup-1 Acta Cryst. (2006). E62, i135–i137

supporting information

Acta Cryst. (2006). E62, i135–i137 [https://doi.org/10.1107/S1600536806017697]

Lead germanium oxide

Yan Xu, Li-Ying Cheng, Guang-Peng Zhou and Yan-Li Wang

(I)

Crystal data

GeO3Pb

Mr = 327.78 Rhombohedral, R3 Hall symbol: -P 3*

a = 9.3282 (2) Å

α = 113.4560 (2)°

V = 512.43 (2) Å3

Z = 6

F(000) = 828

Dx = 6.373 Mg m−3

Mo Kα radiation, λ = 0.71073 Å Cell parameters from 2654 reflections

θ = 2.6–25.5°

µ = 57.82 mm−1

T = 293 K Block, colourless 0.04 × 0.03 × 0.03 mm

Data collection

Bruker Apex2 CCD diffractometer

Radiation source: fine-focus sealed tube Graphite monochromator

ω scans

Absorption correction: multi-scan (SADABS; Sheldrick, 2003)

Tmin = 0.206, Tmax = 0.276

2654 measured reflections 628 independent reflections 553 reflections with I > 2σ(I)

Rint = 0.047

θmax = 25.5°, θmin = 2.6°

h = −10→10

k = −8→7

l = −11→11

Refinement

Refinement on F2 Least-squares matrix: full

R[F2 _{> 2σ(F}2_{)] = 0.050}

wR(F2_{) = 0.164}

S = 1.21 628 reflections 47 parameters 18 restraints

Primary atom site location: structure-invariant direct methods

Secondary atom site location: difference Fourier map

w = 1/[σ2_(F

o2) + (0.1096P)2] where P = (Fo2 + 2Fc2)/3 (Δ/σ)max = 0.001

Δρmax = 4.40 e Å−3 Δρmin = −3.49 e Å−3

Extinction correction: SHELXL, Fc*_{=kFc[1+0.001xFc}2_λ3_/sin(2θ)]-1/4 Extinction coefficient: 0.0022 (8)

Special details

supporting information

sup-2 Acta Cryst. (2006). E62, i135–i137

Refinement. Refinement of F2 _{against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F}2_, conventional R-factors R are based on F, with F set to zero for negative F2_{. The threshold expression of F}2 _{> σ(F}2_{) 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₎

x y z Uiso*/Ueq

Pb1 0.71054 (12) 0.01082 (12) 0.17220 (12) 0.0139 (5) Ge1 1.2560 (3) 0.5203 (3) 0.6560 (3) 0.0114 (7) O1 1.033 (2) 0.287 (2) 0.540 (2) 0.018 (3) O2 1.478 (2) 0.545 (2) 0.777 (2) 0.019 (3) O3 0.684 (2) 0.265 (2) 0.152 (2) 0.020 (3)

Atomic displacement parameters (Å2₎

U11 _U22 _U33 _U12 _U13 _U23

Pb1 0.0151 (6) 0.0162 (6) 0.0148 (6) 0.0111 (5) 0.0112 (5) 0.0108 (5) Ge1 0.0109 (12) 0.0089 (11) 0.0113 (12) 0.0056 (10) 0.0067 (10) 0.0065 (10) O1 0.019 (4) 0.020 (5) 0.015 (4) 0.011 (3) 0.013 (3) 0.012 (3) O2 0.019 (5) 0.017 (4) 0.021 (5) 0.010 (3) 0.012 (3) 0.015 (4) O3 0.017 (4) 0.021 (5) 0.021 (5) 0.013 (3) 0.016 (4) 0.011 (3)

Geometric parameters (Å, º)

Pb1—O1i _{2.270 (14) Ge1—O3}v _{1.725 (15)}

Pb1—O3ii _{2.416 (15) Ge1—O2 1.779 (15)}

Pb1—O1 2.458 (14) Ge1—O2vi _{1.781 (15)}

Pb1—O3 2.551 (16) O1—Pb1vii _{2.270 (14)}

Pb1—O3iii _{2.590 (15) O2—Ge1}viii _{1.781 (15)}

Pb1—Pb1iv _{3.6910 (8) O3—Ge1}v _{1.725 (15)}

Pb1—Pb1ii _{3.6910 (8) O3—Pb1}iv _{2.416 (15)}

Ge1—O1 1.723 (14) O3—Pb1iii _{2.590 (15)}

O1i_—Pb1—O3ii _{78.6 (6) O3}iii_—Pb1—Pb1ii _{118.2 (3)} O1i_{—Pb1—O1 86.5 (5) Pb1}iv_—Pb1—Pb1ii _{118.066 (12)} O3ii_{—Pb1—O1 72.9 (5) O1—Ge1—O3}v _{113.3 (7)}

O1i_{—Pb1—O3 78.1 (5) O1—Ge1—O2 111.9 (7)}

O3ii_{—Pb1—O3 153.4 (5) O3}v_{—Ge1—O2 106.0 (7)}

O1—Pb1—O3 93.1 (5) O1—Ge1—O2vi _{107.6 (7)}

supporting information

sup-3 Acta Cryst. (2006). E62, i135–i137

O3iii_—Pb1—Pb1iv _{92.5 (3) Pb1}iv_{—O3—Pb1 96.0 (5)} O1i_—Pb1—Pb1ii _{121.4 (4) Ge1}v_—O3—Pb1iii _{110.9 (7)} O3ii_—Pb1—Pb1ii _{43.4 (4) Pb1}iv_—O3—Pb1iii _{100.2 (5)} O1—Pb1—Pb1ii _{71.5 (4) Pb1—O3—Pb1}iii _{96.0 (5)} O3—Pb1—Pb1ii _{153.0 (3)}