z KristaOognNCS 218 (2003) 169-170 169 © by Oldenbourg Wissenschaftsverlag, München

Crystal structure of the lM-modification of gallium(III) monohy- drogen triphosphate, lM-CsGaHP3Oi0

J.-X. Mi1, H. Borrmann11, Y.-X. Huang11, J.-T. Zhao*·™ and R. Kniep11 ' Xiamen University, College of Chemistry and Chemical Engineering, Xiamen 361005, P. R. China II Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, D-01187 Dresden, Germany III Shanghai Institute of Ceramics, Chinese Academy of Sciences, State Key Laboratory of High Performance Ceramics, and Superfine Microstructure, 1295 Dingxi Road, Shanghai 200050, P. R. China

Received February 24, 2003, accepted and available on-line June 10, 2003; CSD-No. 409693

(2.525 g) and an excess of 37% HCl (molar ratio Ga : Cs = 1: 1). The mixture was heated to the . The resulting reac- tion product (CsGaCU [1]) was used as reactant for the next step, which was made with a mixture of CsGaCU (3.444 g), Cs(OH) ·

H20 ( 1.679 g) and 5 ml 85% H3PO4 (molar ratio 1:1:7). The start- ing materials were all of analytical grade. The mixture was heated (open system) to the boiling point and kept heating for three days

to evaporate the solvent. Three modifications of CsGaHP3Oio were obtained in the reaction product. The one with a shape of thin plate corresponds to the title compound and was used for the structure determination.

Experimental details The positions of the Η atom was determined from a difference Fourier map.

GaO, Discussion In 1987, Chudinova et al. synthesized a series of caesium gallium phosphates with the common chemical formula CsGaHPaOio and identified four modifications from their powder patterns [2]. Later in 1995, Anisimova et al. [3] reported the structure of the so called modification HL According to our recent systematic struc-

tural investigations, the four modifications of CsGaHP3Oio be- long to the polymorphs series a [4], 1M, 20 and 3M. Here we report on the of the lM-modification. lM-CsGaHP30io is isotypic to (ΝΗ4)Α1ΗΡ3θιο [5]: three-mem- bered [HPO3-O-PO2-O-HPO3] groups stretch in a chain mode along the c axis and link with GaOô octahedra via O-corners to form a two-dimensional layer structure parallel (101). The layers are connected by bonds. Caesium occupies positions between the layers and is ten-fold coordinated by . The Cs—O distances range from 3.098 À to 3.490 Á. The Ga—O bond distances within the coordination octahedra range from 1.920 À to 1.949 Â. The Ρ—O bond distances (ranging from 1.571 A to 1.606 A) for P-O-P bridging oxygen are apparently larger than the (terminal) Ρ—O distances (ranging from 1.489 Â Abstract to 1.520 A). The crystal structures of the four CsGaHP30io poly- CsGaHOioP3, monoclinic, P12i/«1 (No. 13), a = 8.843(1) Á, morphs have a common building unit, i.e. the triphosphate ¿> = 4.9523(5) Â,c = 11.084(1) À,/?= 108.793(6)°, V= 459.5 Â3, [HPO3-O-PO2-O-HPO3]. Within this group the central PO4 z= 2 2, Rgí(F) = 0.042, wRKi(F ) = 0.123, Τ = 295 Κ. shares two further O-corners with two GaOf, octahedra. This to an overall three-dimensional framework structure in the Source of material α-modification and a two-dimensional layer structure in the 1M-, The title compound was synthesized in aqueous solution by two 20-, 3M-modifications. The thickness of one layer is about φοί) steps. In the first step, the reaction was carried out with a mixture = 7.902 A. While in the 20-modification, the structure consists of of GaCl3 (1.046 gallium dissolved in 5 ml 37% HCl), CsCl two layers normal to the c axis, leading to a c axis of 15.722(1) Â, which is about 2 times larger compared with that of the lM-modi- fication. Line-up directions of the three-membered phosphate Correspondence author (e-mail: [email protected]) 170 lM-CsGaHP3Oio

groups in the neighbouring successive layers are paralleled to each other in the lM-modification and normal to each other in the 20-modification, respectively. The cell parameters of the 3M-modification were indexed as a = 11.741(3) Â, è = 4.952(1), c Table 1. Data collection and handling. = 23.705(3), β = 90.03(1)° and this c axis is about 3 times larger compared with that of the lM-modification. It is assumed that its structure within one unit cell should consist of a sequence of three Crystal: transparent colorless thin plate, size 0.05x0.15x0.20 mm layers normal to the c axis. Wavelength: Mo Ka radiation (0.71073 Â) μ: 74.58 cm"1 Diffractometer, scan mode: Rigaku AFC7-CCD, 400 images, Αφ = 0.6° 60-ω scan, Δω = 0.6°, χ = 90° Table 2. Atomic coordinates and displacement parameters (in Â"). 20max: 64.48°

N(hkl)measured, N(hkl)unique: 7193,1456 Atom Site UiSl Criterion for /0bs, N(hkl)gú Us > 2 a(Iobs), 1204 N(param) refined: 72 H(l) 2d 1/2 0.05 Programs: SHELXL-97 [6], DIAMOND [7]

Table 3. Atomic coordinates and displacement parameters (in Â2).

Atom Site x y ζ U π t/22 t/33 U12 t/13 t/23

Cs(l) 2/ 3/4 0.5095(1) 1/4 0.1553(8) 0.0293(3) 0.0462(3) 0 0.0667(4) 0 Ga(l) 2c 0 1/2 0 0.0146(3) 0.0116(3) 0.0108(3) -0.0010(2) 0.0008(2) -0.0005(2) P(l) 4 g 0.7723(1) 0.0010(2) 0.99350(8) 0.0115(4) 0.0126(4) 0.0144(4) 0.0005(3) 0.0027(3) 0.0006(3) P(2) le 1/4 0.7411(3) 1/4 0.0174(5) 0.0118(5) 0.0108(4) 0 -0.0021(4) 0 O(l) % 0.9102(3) 0.1877(5) 0.0539(2) 0.016(1) 0.012(1) 0.015(1) -0.0018(8) 0.0013(8) 0.0014(8) 0(2) 4 g 0.8142(3) 0.7074(5) 0.0039(2) 0.018(1) 0.013(1) 0.023(1) -0.0002(9) 0.0057(9) 0.0021(9) 0(3) 4 g 0.1043(3) 0.5861(6) 0.1787(2) 0.025(1) 0.021(1) 0.012(1) -0.008(1) 0.0001(9) -0.0029(9) 0(4) 4 g 0.2013(4) 0.9341(7) 0.3438(3) 0.031(2) 0.029(2) 0.019(1) 0.016(1) -0.007(1) -0.008(1) 0(5) 4 g 0.6386(4) 0.0550(8) 0.0487(4) 0.020(1) 0.040(2) 0.045(2) -0.002(1) 0.017(1) -0.011(2)

Acknowledgments. This project was supported by the Fund for Distinguished Young Scholars from the NNSF of China, Fund of the 863 project from the DOST of China, and the Fund from the NNSF of China. JXM and JTZ are in- debted to the financial support from the Max-PIanck-Gesellschaft.

References

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or Ga, and X = CI or Br) and (C6H5)4AS(MC14) (c) (M = Ga or In). Do- a-CsGaHP3Oio. Z. Kristallogr. NCS 218 (2003) 167-168. nor-acceptor bobd energies for MX3-X where M = Al, Ga, In, and X = CI, 5. Averbuch-Pouchot, M. T.; Durif, Α.; Guitel, I. C.: Structure cristalline Br. Inorg. Chem. 14 (1975) 2513-2416. d'un tripolyphosphate acide d'-ammonium: Al(NH4)HP30¡o· 2. Chudinova, Ν. N.; Grunze, I.; Guzeeva, L. S.; Avaliani, Μ. Α.: Synthesis Acta Crystallogr. B33 (1977) 1436-1438. of double condensed cesium gallium phosphates, Inorg. Mater. 23 (1987) 6. Sheldrick, G. M.: SHELXL-97. Program for refining crystal structures. 534-538. University of Götttingen, Germany 1997. 3. Anisimova, N.; Bork, M. ; Hoppe, R.; Meisel, M: Crystal structure of a new 7. Brandenburg, Κ.: DIAMOND Version 2.1a. Crystal Impact GbR, Bonn, acentric CsGaHP3Oio form III. Ζ. Anorg. Allg. Chem. 621 (1995) Germany 1996-2001. 1069-1074.