Disilver(I) trinickel(II) hydrogenphos­phate bis­(phosphate), Ag2Ni3(HPO4)(PO4)2

Abderrazzak Assani; Lahcen El Ammari; Mohammed Zriouil; Mohamed Saadi

doi:10.1107/S1600536811021167

. 2011 Jun 11;67(Pt 7):i40. doi: 10.1107/S1600536811021167

Disilver(I) trinickel(II) hydrogenphosphate bis(phosphate), Ag₂Ni₃(HPO₄)(PO₄)₂

Abderrazzak Assani ^a,^*, Lahcen El Ammari ^a, Mohammed Zriouil ^a, Mohamed Saadi ^a

PMCID: PMC3151764 PMID: 21836825

Abstract

The title compound, Ag₂Ni₃(HPO₄)(PO₄)₂, has been synthesized by the hydrothermal method. Its structure is formed by two types of chains running along the b axis. The first chain results from a linear and continuous succession of NiO₆ octahedra linked to PO₄ tetrahedra by a common vertex. The second chain is built up from two adjacent edge-sharing octahedra (dimers) whose ends are linked to two PO₄ tetrahedra by a common edge. Those two types of chains are linked together by the phosphate groups to form polyhedral sheets parallel to the (001) plane. The three-dimensional framework delimits two types of hexagonal tunnels parallel to the a-axis direction, at (x, 1/2, 0) and (x, 0, 1/2), where the Ag atoms are located. Each silver cation is surrounded by eight O atoms. The same Ag⁺ coordination is found in other phosphates with the alluaudite structure, for example, AgMn₃(PO₄)(HPO₄)₂. Moreover, O—H⋯O hydrogen bonds link three PO₄ tetrahedra so as to build a three-dimensional network.

Related literature

For related applications, see: Viter & Nagornyi (2009 ▶); Gao & Gao (2005 ▶); Clearfield (1988 ▶); Trad et al. (2010 ▶). For compounds with the same structure, see: Assani et al. (2010 ▶, 2011 ▶); Leroux et al. (1995 ▶); Ben Smail & Jouini (2002 ▶).

Experimental

Crystal data

Ag₂Ni₃(HPO₄)(PO₄)₂
M _r = 677.79
Orthorhombic,
a = 12.9233 (3) Å
b = 6.5678 (2) Å
c = 10.6629 (3) Å
V = 905.04 (4) Å³
Z = 4
Mo Kα radiation
μ = 10.98 mm⁻¹
T = 296 K
0.25 × 0.13 × 0.08 mm

Data collection

Bruker X8 APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (MULABS; Blessing, 1995 ▶) T _min = 0.382, T _max = 0.471
3762 measured reflections
1125 independent reflections
1103 reflections with I > 2σ(I)
R _int = 0.017

Refinement

R[F ² > 2σ(F ²)] = 0.024
wR(F ²) = 0.060
S = 1.06
1125 reflections
99 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 1.81 e Å⁻³
Δρ_min = −1.12 e Å⁻³
Absolute structure: Flack (1983 ▶), 467 Friedel pairs
Flack parameter: 0.55 (3)

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT; data reduction: SAINT; 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 ▶) and DIAMOND (Brandenburg, 2006 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811021167/ru2005sup1.cif

e-67-00i40-sup1.cif^{(21.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811021167/ru2005Isup2.hkl

e-67-00i40-Isup2.hkl^{(55.8KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O7—H7⋯O6ⁱ	0.86	2.06	2.847 (6)	151

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.

supplementary crystallographic information

Comment

As the improvement has arisen in the synthesis of a variety of interesting porous materials and open-framework structures, extensive studies are devoted to the metal phosphates which exhibit a rich structural diversity and have been widely studied as catalysts (Viter & Nagornyi, 2009; Gao & Gao, 2005), ion-exchangers (Clearfield, 1988) and as positive electrode in the lithium and sodium batteries (Trad et al. (2010)).

Within this family of compounds, the resulting anionic frameworks, generally constructed from the alternation of PO₄ tetrahedra connected to metal cations in different coordinate geometry MO_n (with n=4, 5 and 6), generate pores and channels offering suitable environment to accommodate different other cations. In our search for new phosphates with microporous framework, our most attention has been paid to the hydrothermal investigation of the A₂O—MO—P₂O₅ systems, with A = monovalent cations and M = divalent cations. Accordingly, we have succeed, for instance, to isolate new form of silver zinc phosphate (γ-AgZnPO₄) related to the ABW zeolite structure (Assani et al. 2010) while the silver magnesium phosphate, namely AgMg₃(PO₄)(HPO₄)₂, represent a new member of the well known alluaudite-like structure family (Assani et al. 2011). The present paper aims to develop the hydrothermal synthesis and the structural characterization of a new silver nickel phosphate, namely, Ag₂Ni₃(HPO₄)(PO₄)₂.

The structure of this compound is formed by two types of chains running along the b axis. The first chain (Ni2P2HO₉)∞ is built up from Ni2 and P2 atoms in special Wyckoff position 4 b (m) of the space group Ima2. This chain results from linear and continuous succession of octahedron (Ni2O₆) and P2O₃OH tetrahedron which share a vertex. The second chain (Ni₂P₂O₁₄)n is built up from two adjacent edge sharing octahedra ((Ni1)₂O₁₀ dimmers) whose ends are linked to two P1O₄ tetrahedra by a common edge (Fig.1). Those chains are linked together by the phosphate groups to form polyhedral sheets parallel to the (0 0 1) plane as shown in Fig.2.

The three dimensional framework delimits two types of hexagonal tunnels running along the a direction, at x 1/2 0 and x 0 1/2 (Fig.3). The Ag2 atom is located at centre of tunnels, this explains the high value of its anisotropic displacement U₁₁, whereas Ag1 is slightly shifted from this center (Wyckoff positions: Ag2 at 2a: 0, 0, z and Ag1 at 2 b: 1/4, y, z). However, each Ag⁺ ion is surrounded by 8 O atoms with different Ag–O distances. Indeed, the first coordination environment of Ag2⁺ is almost square planar with four short Ag2—O distances between 2.373 (4) and 2.421 (4) Å and the other four larger distances are in the range of 2.869 (4) to 3.133 (4) Å. A similar coordination surrounding Ag1⁺ is observed with Ag1—O bond lengths in the range of 2.537 (4)–2.616 (4) Å and the longest bonds are situated between 2.661 (4) and 2.963 (4) Å. The same coordination for this cation is found in other phosphate with alluaudite structure like AgMn₃(PO₄)(HPO₄)₂ (Leroux et al. (1995)) and AgNi₃(PO₄)(HPO₄)₂ (Ben Smail & Jouini (2002)).

Moreover, O—H···O hydrogen bondings link two adjacent P2O₄ tetrahedra via a strong hydrogen bond O7–H7···O6 to two P1O₄ tetrahedra through weak bonds O7–H7···O4 in the way to build an infinite three-dimensional network as shown in Table 1.

Experimental

By means of hydrothermal synthesis, we have isolate a new silver nickel phosphate from the reaction mixture of silver nitrate (AgNO₃; 0.1699 g), metallic nickel (Ni; 0.0881 g), 85%wt phosphoric acid (H₃PO₄; 0,10 ml) and water (12 ml). The hydrothermal treatment was conducted in a 23 ml Teflon-lined autoclave under autogeneous pressure at 468 K for two days. After being filtered off, washed with deionized water and air dried, the reaction product consists of a monophasic green powder and some green parallelepipedic crystals corresponding to the title compound.