Journal of Chemical Co'stallography, Vol. 27, No. 9, 1997
Crystal structure of NH3(CH2)2NH3(BiI4)2"4H20 S. C h a a b o u n i , ll~* S. K a m o u n , ttl and J. Jaud ~2)
Received August 14, 1997
The ethylenediammonium bis tetraiodobismuthate(IlI) tetrahydrate salt is monoclinic with the following unit cell dimensions: a = 7.476(3)A,, b = 13.194(3)A, c = 13.916(9),~, 13 = 95.22(6) ~ space group P2Jc with Z = 2. The structure consists of disordered ethylenediammonium cations, water molecules and polynuclear anions in which slightly distorted [BiI6]3octahedra sharing cis edges are interconnected into chains. The [BiI4]- anions are connected through O(W2)-H--.I hydrogen bonds, so that infinite two dimensional chains parallel to the a axis with anionic period [BiI4(H20)]- are formed in the structure. These chains are themselves interconnected by means of the O - H - - . I and N..-O(I) bonds originating respectively from the water molecules and the ethylenediammonium entities, forming a three-dimensional network. K E Y W O R D S : Crystalline structure; organic iodobismuthate(lII); disordered phase.
Introduction
mixture of C2HtoN212 and Bi203 (molar ratio 1/1). The resulting aqueous solution is then kept at room temperature. After several weeks of evaporation, parallelepiped-shaped monocrystals of EBTIB appeared in the solution. The chemical analysis of bismuth atoms and iodide anions has been carried out. 4 The thermogravimetric analysis shows that the EBTIB crystallizes with four water molecules. Crystal data and summary of intensity data collection and structure refinement are reported in Table I. All ordered atoms have been refined using anisotropic temperature factors, for H atoms and disordered atoms, thermal motions were assumed to be isotropic. The ethylenediammonium cations are disordered, the ( N - C - C - N ) atoms are statistically distributed with occupancy probabilities of 0.5 and 0.25 or 0.75 respectively for the C and N atoms. Attempts were made to refine all the nonhydrogen atoms using anisotropic temperature factors. However, for most of the disordered atoms, strong correlations between variable parameters meant that finally two atoms had to be refined using isotropic temperature factors [N(1) and N(2)]. The hydrogen atoms of water molecules were localized using difference Fourier maps and optimized to fixed positions. Their contributions were isotropically introduced into the calculation but not refined. No attempt was made to locate the H atoms belonging to the organic group.
This work is part of our study of the structures of alkyldiammonium metal halogenides. In the particular case of alkylammonium bismuthate(III) iodides only the following anions can be obtained: [Bi I3-] 1 and the enneahalide [Bi2 I3-]. 23 In these compounds the metal shows a tendency toward distorted octahedral coordination with some rather long B i - I bonds, which is attributed to the aspherical distribution of lone pair electrons at Bi(III). Up to now iodo bismuthate(llI) complexes of ethylenediamine were unknown. In the present work, we describe the crystal structure of the ethylenediammonium bis tetraiodobismuthate(III) tetrahydrate (EBTIB).
Experimental The EBTIB crystals are obtained by dissolving in concentrated HI(57%) solution a stoichiometric
'J~Laboratoire de Cristallochimie du Solide, ENIS, 3038, Sfax (Tunisia). ~2~Centre d'Elaboration de Matrriaux et d'Etudes Structurales, CNRS, BP 4347, 31055 Toulouse Cedex, France. * To whom correspondence should be addressed.
527 1074-154~97/0900-0527512.50/0~ 1997PlenumPublishingCorlx)ration
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Table 1. Crystal data and summary of intensity data collection and structure refinement Compound Color/shape Molecular weight (g tool-t ) Space group Temperature. ~ Cell constants" a. ,g, b, A c, ,~ [3, deg Cell volume, ~,3 Formula units/unit cell D~ I, g c m -3 ix~ I, cm J Diffractometer/scan Radiation. graphite monochromator Max, crystal dimensions, mm Scan width Max. scan speed deg/min Min. scan speed deg/min Standard reflections Decay of standards Reflections measured 20 range, deg. Range of h, k. 1 Reflections with l > 3~r(lfl' F(000) Weights R = ~l IF,,I - IF, I I /~- IF,I R,,' Computer programs a
C 2H mN 2( B i la )2"4H20 Red/parallelepiped 1567.4 P 2 ~/c 25 7.476(3) 13.194(3) 13.916(9) 95.22(6) 1367. I 2 3.807 217.6 Enraf-Nonius CAD-4/w-20 MoKa (h = 0.71070) 0.10 • 0.10 • 0.10 0.38 + 0.41 tan 0 20.1 1.4 2 0 4, 2 2 I, I 3 3 _+4% '4429 2.1 - 20 -< 30.0 +10, - 1 8 , _+19 1906 1332 w = w' [(I - AF)/6(crF)2] 2 0.042 0.049 SHELXS, ~ CRYSTALS, ~' ORTEP 7
" Least-squares refinement based on 25 reflections accurately centered on the goniometer. ~'Corrections Lorentz-polanzation. ' See experimental section. a Neutral scattering factors and anomalous dispersion corrections.
Table 2. Final fractional coordinates and U~q or U,,,,* for NH~(CH,),NH3(BiI~)2.4H20 '~
Atom Bi I(l) I(2) I(3) I(4) O(Wl ) O(W2) C(I) C(21 N(l) N(2) a Ueq
Occ
0.5 0.5 0,75 0,25
x/a
y/b
2/c
0.26233(8) 0.47864(5) 0.09121(4) -0.0638(2) 0.6175(31 0.1033(3) 0.5952(I) 0.3487(4) 0.0571(3) 0.4423(2) 0.5823(I) 0.2622(I) 0.1293(2) 0.3155(2) 0.203811) 0.346(5) 0.375(I) 0.460( I ) 0.653(2) 1).335(I ) 0.335(2) 0.029(4) 0.027(2) 0.101(2) 0.914(3) 0.090(2) 0.0315(2) 0.975(3) 0.416(4) 0.432(5) 0.843(6) 0.468(5) 0.443(2)
-- SI X i E j U i j a,* aj* a, aj.
Ueq(A-~) or Ui,,* (~2) 0.0301(3) 0.040816) 0.0395(6) 0.0476(7) 0.0459(6) 0.085(8) 0.089(2) 0.043(5) 0.018(61 0.042(8)* 0.056(9)*
Table 3. Bond distances (A) and bond angles (~ in NHa(CH, L~NH.~(Bila)2.4H20 Atom Bi--l( I ) Bi--l( I )~ Bi--1(2) Bi--I(2) j' Bi--I(3) Bi--I(4) Bi--Bi" Bi--Bi t' Bi--l( I )---Bi" Bi--ll2)--Bi"
Distance 3.067( I ) 3.223( 1) 3.094( I ) 3.315( I ) 2.960( I ) 2.892( I ) 4.509(3) 4.586(4) 9[.50(3) 91.34(3)
Atoms
N(I)~C(I) N( 1) ~ ( 2 ) C( 1)--C(2) C(2)--N(2) C( 1 ) - - N ( 2 ) I( 1)--l( I )" I( 1)--I(2) 1( I )--I(2) ~' 1(I)--I(3) 1( I )--I(4)
Distance 1.53(3) 1.49(3) 1.49(3) 1.49(3) t.51(7) 4.391(2) 6.152(2) 4.22O(2) 4.231(I) 4.108(3)
N( 1 ) ~ ( I )-~57(2) N( 2)---C( I )--C(2) C( 1)--C(2)--N( I ) C( I )--C(2)--N(2)
10(2) 14(3)
C( 1)~N( I )---C(2 ) C(I )--N(2)~C(2)
10(2) 16(5)
11(2) 12(3)
" Symmetry code = - x , I - y , - : . ~'Symmetry code = I - x , I - y , - = .
In the early refinement stages, the observed reflections were given unit weights, in the final refinement we used the scheme of Tukey and Prince included in the software package. The final anisotropic full-matrix least-squares resulted in convergence of the R factor at 0.042 (R,,. = 0.049) incorporating the weighting scheme: w = w' [(1 - AF)/6(crF)2] 2, where w' is a Chebyshev series with the coefficients 4.22, - 1 . 6 7 , and 2.94. All calculations were performed on an ALLIANT VFX minisuper computer using the CRYSTAL package.
Results and discussion The final atomic coordinates and U~4 or U~,, are given in Table 2. Interatomic distances, bond angles, and the hydrogen bonds scheme are respectively listed in Tables 3 and 4. The atomic arrangement of EBTIB is depicted in Figs. 1 and 2. The crystal structure of EBTIB consists of ethylenediammonium cations, water molecules, and polynuclear anions in which slightly distorted BiI6 octahedron sharing cL~ edges are interconnected into chains parallel to the a axis (Fig. 1). The EBTIB appears to be the first alkyldiammonium iodobismuthate(III) in which [BiL]- chains are formed by double iodine bridges. The [BiI4]- anions share two cis edges with two others neighboring octahedra, and a skew infinite chain is formed in a zigzag
Structure of NH3(CH2)2NH3(BiI4)2"4H20
529
~Y'~
( 3 I~3~
) C
a
)
Fig. 1. Structural projection of NH~(CH2)2NH3(BiI.~).,.4H,Oalong the c axis showing the coordination polyhedra. (For clarity, the organic groups are omitted).
manner parallel to the a axis. Each Bi atom is surrounded by six I atoms forming a distorted octahedral configuration with I - B i - I angles in the range 84.09(3)~ ". The B i - I bond lengths in the anions are given in Table 4. Three types of B i - I distances are present within the BiI6 group: two short B i - I (terminal) distances [2.892(1) and 2.960(1),~],
two longer B i - I (bridging) distances [3.067(1) and 3.094(I)A] and two others long B i - I (bridging) distances [3.223(1) and 3.315(1)A]. These values are comparable with those reported to date.~-3.8 The [BiI4]anions are connected through O ( W 2 ) - H . . - I hydrogen bonds, so that infinite two dimensional chains parallel to the a axis with anionic period [BiI4(H20)]- are
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Chaabouni, K a m o u n , and Jaud
C V
1(z) I-1(2W2)
1(4)
OWl2)
t(tW2) N( C(l)
,4'
b Fig. 2. Schematic view of the structure along the a axis, showing the relative disorder of the ethylenediammonium groups. The occupancy probabilities of the C and N atoms are represented according to the black probability surfaces.
Table 4. Principal intermolecular distances (,~.) and bond angles of the hydrogen bonding scheme O(W)-H
H...I
O(Wl ) - H ( I WI 7" "I( 2)" O ( W I ) - H ( 2 W I ) " "I(3) t' O(W2) - H( 1W2)'' "I(3) O ( W 2 ) - H(2W2)'"I(4)"
1.01 (2) 0.87(2) 1.03(2) 0.81 (2)
2.794(2) 3.305(2) 2.883(3) 3.363(2)
N(I )" "'O(W I )' N(I 7"""O(W2) N(I)'" "1(4)'
2.824(6) 2.862(2) 3.730(3)
N(2)...O(W 1)h N(2)...O(W2)
" Symmetry code = .t,_~ " t - ' ), .~+z. h Symmetry code = l - x , l - y , l - z . " Symmetry code = I +x. y, z.
O(W)--.I
O(W)-H...I
3.680(3) 4.078(3) 3.722(4) 4.159(3)
146.1(17 149.6( I ) 138.7(7) 169.6(I)
2.903(1 ) 2.642(2)
Structure of NHa(CH2)2NH3(BiI4)2"4H20
formed in the structure. The mid-planes of the [BiI4(H20)],"- chains are located at z = 0 and z = 0.5. The ethylenediammonium cations are disordered, so that they seem to be associated in pairs forming a centrosymmetric six-membered ring with a chair conformation. In the present work the type of disorder consists of two equilibrium positions for the ethylened i a m m o n i u m cations between which the cation can jump. Figure 2 gives the characteristics of the reorientational motions for each disordered ethylenediammonium cation. The ethylenediammonium groups have an extensive trans configuration with a noncrystallographic inversion center. These groups are located in channels delimited by the [BiI4(H20)]~- chains. Table 3 reports the principal geometric features of the e t h y l e n e - d i a m m o n i u m groups. They are similar to those observed in some other ethylenediammonium salts such as NH3(CH2)2NH3HPO4, 9 NH3(CH2)2NH3 (H2PO4)2, I~ NH3(CH2)2NH3SiF6, II and NH3(CH2)2NH3SO4.12 The intermolecular hydrogen bonding contacts O W ( 1 ) - H . . . I and N . - . O ( W ) and N.--I(4) provide a linkage between the water molecules, the ethylenedia m m o n i u m entities and the [Biln(H20)]~- chains belonging to two successive (0 2 0) planes. All these hydrogen bonds [ O ( W ) - H . . . I ; N.-.O(W); and N...I types] give rise to a three-dimensional network in the structure and add stability to this compound.
Acknowledgments The authors thank Professor A. Daoud for his interest in this investigation and for many helpful dis-
531
cussions. S.C. is grateful to the members of the Centre d'Elaboration de Mat6riaux et d'Etudes Structuales de Toulouse, for their hospitality during his stay at their laboratory.
Supplementary material. Crystallographic data (excluding structure factors) for the structure reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-1003/5210. Copies of available material can be obtained, free of charge, on application to the CCDC, 12 Union Road, Cambridge CB2 IEZ. UK, (fax: +44(0)1223-336033 or e-mail:
[email protected]).
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