Bis(3-ammonio­methyl­pyridinium) cyclo­tetra­phosphate

Hemissi, H.; Rzaigui, M.; Al-Deyab, S.S.

doi:10.1107/S1600536810008056

organic compounds

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ISSN: 2056-9890

Volume 66| Part 4| April 2010| Pages o779-o780

doi:10.1107/S1600536810008056

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Bis(3-ammoniomethylpyridinium) cyclotetraphosphate

Hanène Hemissi,^a ^* Mohammed Rzaigui ^a and Salem S. Al-Deyab ^b

^aLaboratoire de Chimie des Matériaux, Faculté des Sciences de Bizerte, 7021 Zarzouna Bizerte, Tunisia, and ^bPetrochemical Research Chair, College of Science, King Saud University, Riyadh, Saudi Arabia
^*Correspondence e-mail: hanene.hemissi@fsb.rnu.tn

(Received 18 February 2010; accepted 2 March 2010; online 10 March 2010)

In the title compound, 2C₆H₁₀N₂²⁺·P₄O₁₂⁴⁻, which involves a doubly protonated 3-ammoniomethylpyridinium cation and a cyclotetraphosphate anion, the cyclotetraphosphoric ring is arranged around an inversion center and the organic entity alternates with it, forming hybrid ribbons parallel to the b axis. The crystal structure is stabilized by a three-dimensional network of N—H⋯O and weaker C—H⋯O hydrogen bonds.

Related literature

For properties of hybrid materials, see: Aakeröy et al.(1989 ); Sankar et al. (1993 ); Teraski et al. (1987 ); Vaughan (1993 ); Centi (1993 ); Ozin (1992 ). For related structures containing phosphoric acid rings, see: Aloui et al. (2003 ); Hemissi et al. (2005 ); Averbuch-Pouchot & Durif (1991 ); Durif (1995 ). For bond lengths in pyridine, see: Bak et al. (1959 ). For hydrogen bonding, see: Blessing (1986 ); Brown (1976 ); Soumhi & Jouini (1996 ). Cyclotetraphosphoric acid was produced from Na₄P₄O₁₂·4H₂O, which was prepared according to the Ondik (1964 ) process.

Experimental

Crystal data

2C₆H₁₀N₂²⁺·P₄O₁₂⁴⁻
M_r = 536.20
Triclinic, $[P \overline 1]$
a = 7.849 (2) Å
b = 8.384 (2) Å
c = 9.448 (2) Å
α = 113.24 (2)°
β = 98.73 (3)°
γ = 108.76 (3)°
V = 512.4 (2) Å³
Z = 1
Ag Kα radiation
λ = 0.56083 Å
μ = 0.23 mm⁻¹
T = 293 K
0.35 × 0.3 × 0.15 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
7923 measured reflections
5005 independent reflections
3963 reflections with I > 2σ(I)
R_int = 0.012
2 standard reflections every 120 min intensity decay: 1%

Refinement

R[F² > 2σ(F²)] = 0.034
wR(F²) = 0.101
S = 1.08
5005 reflections
145 parameters
H-atom parameters constrained
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.47 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O6	0.86	1.77	2.6294 (18)	175
N2—H2A⋯O5ⁱ	0.89	1.88	2.7079 (17)	154
N2—H2B⋯O3ⁱⁱ	0.89	2.02	2.7350 (17)	137
N2—H2C⋯O1ⁱⁱⁱ	0.89	2.08	2.831 (2)	141
C1—H1A⋯O6^iv	0.93	2.55	3.381 (2)	149
C4—H4⋯O5^v	0.93	2.48	3.281 (2)	144
C5—H5⋯O4	0.93	2.60	3.256 (2)	128
C6—H6B⋯O1ⁱ	0.97	2.44	3.117 (2)	127
Symmetry codes: (i) x+1, y, z+1; (ii) x, y, z+1; (iii) -x+1, -y+1, -z+1; (iv) -x, -y, -z+1; (v) x+1, y, z.

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1996 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810008056/dn2541sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810008056/dn2541Isup2.hkl

checkCIF report

Comment top

Hybrid materials with organic and inorganic components continue to be a focus area in solid state chemistry and material sciences due to their potential applications in various fields, such as nonlinear optics (Aakeröy et al., 1989), heterogeneous catalysis (Centi, 1993), photochemical and photophysical process (Ozin, 1992), molecular sieves (Vaughan, 1993), ceramic precursors (Sankar et al., 1993) and other areas that include electronic materials (Teraski et al., 1987). In the present paper, the results of the x-ray structure analysis of a new organic cyclotetraphosphate, bis(3-ammoniomethylpyridinium) cyclotetraphosphate, are discussed with respect to the geometry and flexibility of the cyclotetraphosphate ring system and H-bonding interactions between the inorganic acceptor and the organic donor molecules.

The chemical composition of the title compound (I) includes two fundamental entities, the P₄O₁₂^4- ring and the organic cations (C₆H₁₀N₂)²⁺. The geometrical configuration of these entities is depicted in Figure 1, while the complete atomic arrangement is shown in Figure 2. This latter shows that the crystal structure of (C₆H₁₀N₂)₂P₄O₁₂ can be described by hybrid ribbons where the organic and inorganic species are alternated. These ribbons, extended in the b-direction, are also connected between them in the two other directions via H-bonds to develop a three-dimensional network. The P₄O₁₂ rings are located around the inversion center (0, 0, 0) and are built up by only two independent PO₄ tetrahedra. The P—P—P angles are 84.43 (1) and 95.57 (1)° and show that the tetramembered phosphoric rings are distorted in comparison with the ideal value (90°). It should be noted that such deviations are commonly observed in cyclotetraphosphoric ring anions with low internal symmetry as (I) (Aloui et al., 2003; Hemissi et al., 2005). Nevertheless, this distortion is comparatively less important than that observed in the hexamembered P₆O₁₈ rings (93.2 - 145.5°) (Averbuch-Pouchot & Durif, 1991). Consequently, P₄O₁₂ is less flexible than the P₆O₁₈ what could explain the pronounced distortion observed for the big rings compared with their smaller rings analogues. In spite of this distortion, the examination of the main geometrical feature of PO₄ tetrahedra (P—O distances and P—O—P angles) shows that they are in accordance with values generally observed in condensed phosphates (Durif, 1995).

One crystallographically independent organic group exists in the asymmetric unit. Inside this organic molecule, both nitrogen atoms are protonated and so it is formulated (C₆H₁₀N₂)²⁺. The examination of pyridinium ring shows that this unit is essentially planar with mean deviation of ±0.0036 Å from least-square plane defined by the six constituent atoms. The average C—N distances in pyridinium ring is 1.337 (2) Å and of the C—C bond lengths is 1.384 (2) Å. The latter value, being shorter than 1.39-1.41 Å, reported for non-substituent pyridine, may indicate some aromatic bond characters (Bak et al., 1959). The pyridinium ring is non coplanar with its methylamine substituent (-CH₂—NH₃) which is evidenced by the torsion angle value of (C1—C2—C6—N2) equal to 96.29 (2)°. In addition to electrostatic and van der Waals interactions, the structure is further stabilized with a three-dimensional network of N—H···O and the weaker C—H···O hydrogen bonds (Table 1, Fig. 2)). In the hydrogen-bond scheme two main points should be noticed: (i) there is a bridging oxygen atom (O4) of the P₄O₁₂ ring involved in hydrogen bond and so that is rarely observed in organic condensed phosphates. Indeed, it was only observed in (C₆H₁₀N₂)₂P₄O₁₂.2H₂O (Soumhi et al., 1996). (ii) Inside the structure, there are two strong hydrogen bonds with N···O distances equal to 2.629 (2) and 2.708 (2) Å. The others are weaker within N(C)···O distances falling from 2.735 (2) to 3.381 (2) Å (Brown, 1976; Blessing, 1986).

Related literature top

For properties of hybrid materials, see: Aakeröy et al.(1989); Sankar et al. (1993); Teraski et al. (1987); Vaughan (1993); Centi (1993); Ozin (1992). For related structures containing phosphoric rings, see: Aloui et al. (2003); Hemissi et al. (2005); Averbuch-Pouchot & Durif (1991); Durif (1995). For bond lengths in pyridine, see: Bak et al. (1959). For hydrogen bonding, see: Blessing (1986); Brown (1976); Soumhi & Jouini (1996). Cyclotetraphosphoric acid was produced from Na₄P₄O₁₂.4H₂O, which was prepared according to the Ondik (1964) process.

Experimental top

Crystals of the title compound were prepared by adding ethanolic solution (5 ml) of 3-aminopicolamine (11.04 mmol) dropwise to an aqueous solution of cyclotetraphosphoric acid (5.52 mmol, 20 ml). Good quality of colourless prisms were obtained after a slow evaporation during few days at ambient temperature. The cyclotetraphosphoric acid H₄P₄O₁₂, was produced from Na₄P₄O₁₂.4H₂O, prepared according to the Ondik process (Ondik, 1964), through an ion-exchange resin in H-state (Amberlite IR 120).

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

	Fig. 1. An ORTEP view of (I) with the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii. [Symmetry codes: (i) 1 - x, 1 - y, 1 - z].
	Fig. 2. Projection of (I) along a axis.

Bis(3-ammoniomethylpyridinium) cyclotetraphosphate top

Crystal data top

2C₆H₁₀N₂²⁺·P₄O₁₂⁴⁻	Z = 1
M_r = 536.20	F(000) = 276
Triclinic, P1	D_x = 1.738 Mg m⁻³
Hall symbol: -P 1	Ag Kα radiation, λ = 0.56083 Å
a = 7.849 (2) Å	Cell parameters from 25 reflections
b = 8.384 (2) Å	θ = 9.0–10.7°
c = 9.448 (2) Å	µ = 0.23 mm⁻¹
α = 113.24 (2)°	T = 293 K
β = 98.73 (3)°	Prism, colourless
γ = 108.76 (3)°	0.35 × 0.3 × 0.15 mm
V = 512.4 (2) Å³

Data collection top

Enraf–Nonius CAD-4 diffractometer	R_int = 0.012
Radiation source: Enraf–Nonius FR590	θ_max = 28.0°, θ_min = 2.2°
Graphite monochromator	h = −13→13
non–profiled ω scans	k = −14→14
7923 measured reflections	l = −6→15
5005 independent reflections	2 standard reflections every 120 min
3963 reflections with I > 2σ(I)	intensity decay: 1%

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.101	H-atom parameters constrained
S = 1.08	w = 1/[σ²(F_o²) + (0.049P)² + 0.1514P] where P = (F_o² + 2F_c²)/3
5005 reflections	(Δ/σ)_max = 0.001
145 parameters	Δρ_max = 0.49 e Å⁻³
0 restraints	Δρ_min = −0.47 e Å⁻³

Crystal data top

2C₆H₁₀N₂²⁺·P₄O₁₂⁴⁻	γ = 108.76 (3)°
M_r = 536.20	V = 512.4 (2) Å³
Triclinic, P1	Z = 1
a = 7.849 (2) Å	Ag Kα radiation, λ = 0.56083 Å
b = 8.384 (2) Å	µ = 0.23 mm⁻¹
c = 9.448 (2) Å	T = 293 K
α = 113.24 (2)°	0.35 × 0.3 × 0.15 mm
β = 98.73 (3)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	R_int = 0.012
7923 measured reflections	2 standard reflections every 120 min
5005 independent reflections	intensity decay: 1%
3963 reflections with I > 2σ(I)

Refinement top

R[F² > 2σ(F²)] = 0.034	0 restraints
wR(F²) = 0.101	H-atom parameters constrained
S = 1.08	Δρ_max = 0.49 e Å⁻³
5005 reflections	Δρ_min = −0.47 e Å⁻³
145 parameters

Special details top

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

	x	y	z	U_iso*/U_eq
O4	0.14028 (12)	0.17020 (14)	0.16858 (12)	0.02591 (17)
O2	0.20484 (12)	0.04327 (13)	−0.08942 (12)	0.02816 (18)
O1	0.07961 (14)	0.30061 (15)	−0.02599 (13)	0.03096 (19)
O3	0.41615 (12)	0.37060 (14)	0.12629 (14)	0.0328 (2)
O5	−0.09804 (14)	0.30451 (14)	0.25390 (12)	0.02842 (18)
O6	0.01424 (14)	0.12073 (17)	0.37735 (13)	0.0330 (2)
P1	0.21242 (4)	0.23999 (4)	0.04410 (4)	0.02125 (7)
P2	−0.03708 (4)	0.15037 (4)	0.23497 (4)	0.02013 (7)
N2	0.71399 (14)	0.34670 (15)	1.01546 (13)	0.02438 (18)
H2A	0.7405	0.3187	1.0954	0.037*
H2B	0.6259	0.3920	1.0259	0.037*
H2C	0.8188	0.4345	1.0204	0.037*
N1	0.37134 (15)	0.21366 (16)	0.52122 (14)	0.0284 (2)
H1	0.2559	0.1902	0.4771	0.034*
C1	0.41069 (16)	0.17716 (18)	0.64460 (16)	0.0259 (2)
H1A	0.3140	0.1291	0.6824	0.031*
C4	0.6907 (2)	0.3225 (2)	0.53050 (17)	0.0320 (3)
H4	0.7847	0.3727	0.4913	0.038*
C6	0.64164 (17)	0.17070 (18)	0.85588 (16)	0.0264 (2)
H6A	0.5287	0.0744	0.8515	0.032*
H6B	0.7369	0.1203	0.8456	0.032*
C2	0.59489 (16)	0.21046 (16)	0.71693 (14)	0.02293 (19)
C5	0.5057 (2)	0.28559 (19)	0.46376 (16)	0.0309 (2)
H5	0.4735	0.3106	0.3784	0.037*
C3	0.73527 (17)	0.28345 (19)	0.65771 (16)	0.0288 (2)
H3	0.8598	0.3064	0.7034	0.035*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O4	0.0190 (3)	0.0374 (5)	0.0315 (4)	0.0132 (3)	0.0114 (3)	0.0233 (4)
O2	0.0190 (3)	0.0275 (4)	0.0306 (4)	0.0079 (3)	0.0068 (3)	0.0089 (3)
O1	0.0281 (4)	0.0376 (5)	0.0413 (5)	0.0170 (4)	0.0131 (4)	0.0284 (4)
O3	0.0174 (3)	0.0290 (4)	0.0409 (5)	0.0034 (3)	0.0105 (3)	0.0109 (4)
O5	0.0331 (4)	0.0325 (4)	0.0273 (4)	0.0199 (4)	0.0114 (4)	0.0157 (4)
O6	0.0267 (4)	0.0532 (6)	0.0328 (5)	0.0175 (4)	0.0104 (4)	0.0320 (5)
P1	0.01556 (11)	0.02324 (13)	0.02726 (14)	0.00693 (9)	0.00856 (10)	0.01444 (11)
P2	0.01707 (11)	0.02625 (13)	0.02125 (13)	0.00966 (10)	0.00632 (9)	0.01460 (11)
N2	0.0213 (4)	0.0309 (5)	0.0267 (4)	0.0122 (3)	0.0078 (3)	0.0180 (4)
N1	0.0235 (4)	0.0314 (5)	0.0285 (5)	0.0109 (4)	0.0019 (4)	0.0152 (4)
C1	0.0198 (4)	0.0305 (5)	0.0293 (5)	0.0101 (4)	0.0065 (4)	0.0167 (5)
C4	0.0303 (6)	0.0337 (6)	0.0281 (6)	0.0080 (5)	0.0117 (5)	0.0146 (5)
C6	0.0250 (5)	0.0289 (5)	0.0287 (5)	0.0123 (4)	0.0054 (4)	0.0172 (4)
C2	0.0197 (4)	0.0245 (5)	0.0235 (5)	0.0091 (4)	0.0047 (4)	0.0114 (4)
C5	0.0360 (6)	0.0298 (6)	0.0248 (5)	0.0116 (5)	0.0055 (5)	0.0143 (5)
C3	0.0201 (4)	0.0345 (6)	0.0284 (6)	0.0092 (4)	0.0073 (4)	0.0137 (5)

Geometric parameters (Å, º) top

O4—P2	1.5992 (10)	N1—C5	1.3393 (19)
O4—P1	1.6057 (10)	N1—H1	0.8600
O2—P2ⁱ	1.6044 (14)	C1—C2	1.3875 (17)
O2—P1	1.6085 (11)	C1—H1A	0.9300
O1—P1	1.4766 (10)	C4—C5	1.372 (2)
O3—P1	1.4781 (12)	C4—C3	1.389 (2)
O5—P2	1.4739 (10)	C4—H4	0.9300
O6—P2	1.4824 (10)	C6—C2	1.4990 (17)
P2—O2ⁱ	1.6044 (14)	C6—H6A	0.9700
N2—C6	1.4894 (18)	C6—H6B	0.9700
N2—H2A	0.8900	C2—C3	1.3875 (18)
N2—H2B	0.8900	C5—H5	0.9300
N2—H2C	0.8900	C3—H3	0.9300
N1—C1	1.3345 (17)

P2—O4—P1	136.26 (6)	C5—N1—H1	118.9
P2ⁱ—O2—P1	134.03 (6)	N1—C1—C2	120.46 (12)
O1—P1—O3	120.41 (7)	N1—C1—H1A	119.8
O1—P1—O4	110.99 (6)	C2—C1—H1A	119.8
O3—P1—O4	106.65 (6)	C5—C4—C3	118.82 (13)
O1—P1—O2	111.42 (7)	C5—C4—H4	120.6
O3—P1—O2	105.82 (7)	C3—C4—H4	120.6
O4—P1—O2	99.36 (6)	N2—C6—C2	111.53 (10)
O5—P2—O6	119.04 (7)	N2—C6—H6A	109.3
O5—P2—O4	112.23 (6)	C2—C6—H6A	109.3
O6—P2—O4	105.42 (6)	N2—C6—H6B	109.3
O5—P2—O2ⁱ	106.33 (6)	C2—C6—H6B	109.3
O6—P2—O2ⁱ	109.45 (7)	H6A—C6—H6B	108.0
O4—P2—O2ⁱ	103.28 (6)	C3—C2—C1	117.98 (11)
C6—N2—H2A	109.5	C3—C2—C6	120.87 (11)
C6—N2—H2B	109.5	C1—C2—C6	121.15 (11)
H2A—N2—H2B	109.5	N1—C5—C4	120.20 (12)
C6—N2—H2C	109.5	N1—C5—H5	119.9
H2A—N2—H2C	109.5	C4—C5—H5	119.9
H2B—N2—H2C	109.5	C2—C3—C4	120.36 (12)
C1—N1—C5	122.18 (11)	C2—C3—H3	119.8
C1—N1—H1	118.9	C4—C3—H3	119.8

Symmetry code: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O6	0.86	1.77	2.6294 (18)	175
N2—H2A···O5ⁱⁱ	0.89	1.88	2.7079 (17)	154
N2—H2B···O3ⁱⁱⁱ	0.89	2.02	2.7350 (17)	137
N2—H2C···O1^iv	0.89	2.08	2.831 (2)	141
C1—H1A···O6^v	0.93	2.55	3.381 (2)	149
C4—H4···O5^vi	0.93	2.48	3.281 (2)	144
C5—H5···O4	0.93	2.60	3.256 (2)	128
C6—H6B···O1ⁱⁱ	0.97	2.44	3.117 (2)	127

Symmetry codes: (ii) x+1, y, z+1; (iii) x, y, z+1; (iv) −x+1, −y+1, −z+1; (v) −x, −y, −z+1; (vi) x+1, y, z.

Experimental details

Crystal data
Chemical formula	2C₆H₁₀N₂²⁺·P₄O₁₂⁴⁻
M_r	536.20
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	7.849 (2), 8.384 (2), 9.448 (2)
α, β, γ (°)	113.24 (2), 98.73 (3), 108.76 (3)
V (Å³)	512.4 (2)
Z	1
Radiation type	Ag Kα, λ = 0.56083 Å
µ (mm⁻¹)	0.23
Crystal size (mm)	0.35 × 0.3 × 0.15

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	7923, 5005, 3963
R_int	0.012
(sin θ/λ)_max (Å⁻¹)	0.836

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.034, 0.101, 1.08
No. of reflections	5005
No. of parameters	145
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.49, −0.47

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994), XCAD4 (Harms & Wocadlo, 1996), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O6	0.8600	1.7700	2.6294 (18)	175.00
N2—H2A···O5ⁱ	0.8900	1.8800	2.7079 (17)	154.00
N2—H2B···O3ⁱⁱ	0.8900	2.0200	2.7350 (17)	137.00
N2—H2C···O1ⁱⁱⁱ	0.8900	2.0800	2.831 (2)	141.00
C1—H1A···O6^iv	0.9300	2.5500	3.381 (2)	149.00
C4—H4···O5^v	0.9300	2.4800	3.281 (2)	144.00
C5—H5···O4	0.9300	2.6000	3.256 (2)	128.00
C6—H6B···O1ⁱ	0.9700	2.4400	3.117 (2)	127.00

Symmetry codes: (i) x+1, y, z+1; (ii) x, y, z+1; (iii) −x+1, −y+1, −z+1; (iv) −x, −y, −z+1; (v) x+1, y, z.

References

Aakeröy, C. B., Hitchcock, P. B., Moyle, B. D. & Seddon, K. R. (1989). J. Chem. Soc. Chem. Commun. pp. 1856–1859. Google Scholar
Aloui, Z., Abid, S. & Rzaigui, M. (2003). J. Phys. Chem. Solids, 65, 923–926 Web of Science CSD CrossRef Google Scholar
Averbuch-Pouchot, M. T. & Durif, A. (1991). Eur. J. Solid State Inorg. Chem. 28, 9–22. CAS Google Scholar
Bak, B., Hansen-Nygaard, L. & Rastrup-Andersen, J. (1959). J. Mol. Spectrosc. 2, 361–364. CrossRef Web of Science Google Scholar
Blessing, R. H. (1986). Acta Cryst. B42, 613–621. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Brown, I. D. (1976). Acta Cryst. A32, 24–31. CrossRef IUCr Journals Web of Science Google Scholar
Centi, G. (1993). Catal. Lett. 22, 53–66. CrossRef CAS Google Scholar
Durif, A. (1995). Crystal Chemistry of Condensed Phosphates. New York: Plenum Press. Google Scholar
Enraf–Nonius (1994). CAD-4 EXPRESS. Enraf–Nonius, Delft, The Netherlands. Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838. CrossRef CAS IUCr Journals Google Scholar
Harms, K. & Wocadlo, S. (1996). XCAD4. University of Marburg, Germany. Google Scholar
Hemissi, H., Sonia, A. & Rzaigui, M. (2005). Z. Kristallogr. 220, 265–266 CAS Google Scholar
Ondik, H. M. (1964). Acta Cryst. 17, 1139–1145. CrossRef CAS IUCr Journals Web of Science Google Scholar
Ozin, G. A. (1992). Adv. Mater. 4, 612-649. CrossRef CAS Web of Science Google Scholar
Sankar, G., Wright, P. A., Natarajan, S., Thomas, J. M., Greaves, G. N., Dent, A. J., Dobson, B. R., Ramsdale, C. A. & Jones, R. H. (1993). J. Phys. Chem. 97, 9550-9554. CrossRef CAS Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Soumhi, E. H. & Jouini, T. (1996). Acta Cryst. C52, 432–433. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Teraski, O., Barry, J. C. & Thomas, J. M. (1987). Nature (London), 330, 58-60 Google Scholar
Vaughan, D. E. W. (1993). In Multifunctional Mesoporous Inorganic Solids, edited by A.C. Seqina & M.I. Hudson, pp. 137–156. New York: Nato ASI Series. Google Scholar

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Volume 66| Part 4| April 2010| Pages o779-o780

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