research communications
4Co7−xAl0.67x(As1−yPyO4)6 (x = 1.60; y = 0.116)
of NaaUniversité de Tunis El Manar, Faculté des Sciences, Laboratoire de Matériaux, Cristallochimie et Thermodynamique Appliquée, El Manar II, 2092 Tunis, Tunisia, bUniversité de Tunis, Institut Préparatoire aux Etudes d'Ingénieurs de Tunis, Rue Jawaher Lel Nehru, 1089 Montfleury, Tunis, Tunisia, and cAl-Baha University, Faculty of Sciences and Arts in Al Mukhwah, Al Mukhwah, Al Baha Region, Kingdom of Saudi Arabia
*Correspondence e-mail: abderrahmen.guesmi@ipeim.rnu.tn
The title compound, tetrasodium hepta(cobalt/aluminium) hexa(arsenate/phosphate), Na4Co5.40Al1.07(As0.883P0.116O4)6, was prepared by a solid-state reaction. It is a new member of the family of isostructural compounds with the general formula A4M7(XO4)6 (A: Na, K; M: Ni, Co; X: P, As) that is most similar to Na4Co5.63Al0.91(AsO4)6. The Co2+ ions in the title compound are substituted by Al3+ in a fully occupied octahedral site (site symmetry 2/m) and a partially occupied tetrahedral site (site symmetry 2). A third octahedral site is fully occupied by Co2+ ions only. With regard to the P and As atoms, one site (site symmetry m) is simultaneously occupied by As and P, whereas in the second site there is only arsenic. The alkali cations are, as in the isostructural compounds, distributed over half-occupied crystallographic sites, with a positional disorder of one of them. The proposed structural model is based both on a careful investigation of the crystal data, as well as validation by means of bond-valence-sum (BVS) and charge-distribution (CHARDI) calculations. The correlation between the X-ray and the validation results is discussed.
Keywords: crystal structure; Na4Co5.40Al1.07(As0.883P0.116O4)6; bond-valence sum; charge distribution.
CCDC reference: 1462882
1. Chemical context
Metal-substituted aluminophosphates and aluminoarsenates form an important group of materials with many interesting properties such as molecular sieves, catalysts, etc. Li et al. (2012) reported the progress in heteroatom-containing aluminophosphate molecular sieves. With regard to their As homologues, one can cite AlAsO4-5 and AlAsO4-6, two aluminoarsenates with occluded ethylenediamine (Chen et al. 1990). The analogous cobalt compounds, such as ammonium-templated cobalt aluminophosphates with zeolite-like structures (Bontchev & Sevov, 1999), possess similar structural properties.
The title compound, Na4Co7−xAl0.67x(As1−yPyO4)6 (x = 1.60; y = 0.116), was obtained during the exploration of the Na–Co–P–As–O system by solid-state reaction; as for many aluminophosphates, aluminum was incorporated from the reaction container. The chemical composition and were determined by energy-dispersive (EDX) analysis (Fig. 1) and single-crystal X-ray diffraction; the proposed structural model is supported by validation tools by means of bond-valence-sum (BVS) calculations and charge-distribution (CHARDI) analysis (Brown, 2002; Adams, 2003, Nespolo, 2015, 2016; Eon & Nespolo, 2015). The correlation between the experimental and the validation results is discussed.
2. Structural commentary
The title compound is a new member of the isostructural compounds family with the general formula A4M7(XO4)6 (A: Na, K; M: Ni, Co; X: P, As) (Moring & Kostiner, 1986; Kobashi et al., 1998; Ben Smail et al., 1999; Marzouki et al., 2010, 2013).
The ) contains seven metallic sites of which four are occupied by Na+ cations (occupancies ranging from 0.23 to 0.50) with eight cations per two others (denoted MA and MB) are simultaneously shared by Co2+ and Al3+ ions, and one is fully occupied by Co2+ ions: the same distribution is observed in the homologous arsenate Na4Co7−xAl0.67x(AsO4)6 (x = 1.37) (II) (Marzouki et al., 2010).
of the title compound (I) (Fig. 23. Validation of the structural model using BVS and CHARDI
Two validation tools, BVS and CHARDI, are used to support and analyse the proposed structural model. Briefly, for a properly refined structure, the valences V according to the BVS model and charges Q from the CHARDI analysis should agree with the oxidation states of the atoms (Brown, 2002; Adams, 2003, Nespolo, 2015, 2016; Eon & Nespolo, 2015).
The MA site, with an octahedral environment by oxygen atoms, is fully occupied by the two cations with overall occupancy Co0.189Al0.811. This distribution scheme is confirmed by the validation tools, with a better convergence with the CHARDI model (Table 1). If compared to the homologous site in (II) with overall occupancy Co0.286Al0.714 (Marzouki et al., 2010), the average arithmetic distance in (I) (1.91 Å) is smaller than in (II) (1.96 Å) due to the higher fraction of the small cation (Al3+) in (I).
For the MB site with a tetrahedral coordination, the Co2+/Al3+ distribution is based on the same observations as in (II), mainly if it is refined as partially occupied by just Co2+, the charge neutrality is not achieved, and then a fraction of Al3+ was introduced in the MB site yielding an overall occupancy distribution of Co0.605Al0.135□0.260, with □ expressing the vacancy. The validation results for this particular distribution are: V(MB) = 1.31 and Q(MB) = 1.58, the theoretical value is 1.61 (Table 1). Finally, with regard to P and As atoms, the P/As substitutional disorder is observed in one of the two sites (MC): P/As = 0.35/0.65; V = 5.21 and Q = 5.00.
The final result corresponds to the formula Na4Co5.40Al1.07(As0.883P0.116O4)6. It is the first case in its homologous family which contains such a number of elements. The similarity to (II) (Marzouki et al., 2010) is clear, the cell parameters of (I) are smaller than those of (II) as it contains more small elements than (II). The CHARDI method is extended, as for (II), to analyse the coordination polyhedra by means of the Effective Coordination Numbers (ECoN): the polyhedron distortion is more pronounced if the ECoN deviates more from the classical (CN).
The framework of the title compound is of an open character (Fig. 3). Its aptitude for sodium conduction through the tunnels appears to be possible, as shown in experimental and theoretical studies for the similar compound (II) (Marzouki et al., 2013). These studies will be the subject of future works.
4. Synthesis and crystallization
A mixture of sodium nitrate, cobalt nitrate hexahydrate, NH4H2XO4 (X: P, As) in the molar ratio Na:Co:P:As = 2:1:0.5:1 was dissolved in deionized water and then heated at 373 K to dehydration. After grinding, it was placed in a porcelain boat and first heated at 673 K in air for 24 h and then heated gradually to 1123 K for 1 d. Some pink parallelepiped-shaped crystals were isolated from the sample. A qualitative EDX analysis confirmed the presence of Na, Co, Al, As and O (Fig. 1), with the aluminium diffusing from the reaction container.
5. Refinement
Crystal data, data collection and structure . The Co and Al atoms occupying the MA and MB sites, as well as the P and As atoms occupying the MC site, were constrained using the EXYZ and EADP instructions of SHELXL97 (Sheldrick, 2008). Three linear free variable restraints (SUMP) were required to restrain the sum of their occupation factors. The Na1 and Na2 cations are at half-occupancy sites and the two others (Na31 and Na32) with isotropic have a total occupancy of 0.50 because, when refined freely, their occupations converged to these values.
details are summarized in Table 2
|
Supporting information
CCDC reference: 1462882
https://doi.org/10.1107/S205698901600400X/br2258sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698901600400X/br2258Isup2.hkl
Data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); cell
CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: WinGX (Farrugia, 2012) and publCIF (Westrip, 2010).Na4Co5.40Al1.07(As0.883P0.116O4)6 | F(000) = 1162 |
Mr = 1242.08 | Dx = 4.187 Mg m−3 |
Monoclinic, C2/m | Mo Kα radiation, λ = 0.71073 Å |
a = 10.5797 (2) Å | Cell parameters from 25 reflections |
b = 14.5528 (3) Å | θ = 12.0–14.8° |
c = 6.6441 (3) Å | µ = 13.60 mm−1 |
β = 105.608 (9)° | T = 293 K |
V = 985.23 (7) Å3 | Parallelepiped, pink |
Z = 2 | 0.30 × 0.20 × 0.20 mm |
Enraf–Nonius CAD-4 diffractometer | Rint = 0.027 |
ω/2θ scans | θmax = 27.0°, θmin = 2.4° |
Absorption correction: ψ scan (North et al., 1968) | h = −13→13 |
Tmin = 0.055, Tmax = 0.140 | k = −1→18 |
2409 measured reflections | l = −8→8 |
1124 independent reflections | 2 standard reflections every 120 reflections |
894 reflections with I > 2σ(I) | intensity decay: 1% |
Refinement on F2 | 117 parameters |
Least-squares matrix: full | 2 restraints |
R[F2 > 2σ(F2)] = 0.030 | w = 1/[σ2(Fo2) + (0.0401P)2 + 10.5538P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.083 | (Δ/σ)max < 0.001 |
S = 1.07 | Δρmax = 0.81 e Å−3 |
1124 reflections | Δρmin = −0.85 e Å−3 |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Co1 | 0.0000 | 0.0000 | 0.0000 | 0.0064 (9) | 0.189 (13) |
Al1 | 0.0000 | 0.0000 | 0.0000 | 0.0064 (9) | 0.811 (13) |
Co2 | −0.5000 | 0.16324 (13) | 0.0000 | 0.0118 (6) | 0.605 (9) |
Al2 | −0.5000 | 0.16324 (13) | 0.0000 | 0.0118 (6) | 0.135 (9) |
Co3 | −0.18046 (7) | 0.18027 (5) | 0.17925 (10) | 0.0062 (2) | |
As1 | −0.32397 (10) | 0.0000 | −0.06479 (16) | 0.0091 (4) | 0.649 (7) |
P1 | −0.32397 (10) | 0.0000 | −0.06479 (16) | 0.0091 (4) | 0.351 (7) |
As2 | 0.09963 (5) | 0.17931 (4) | 0.29004 (8) | 0.00940 (18) | |
Na1 | −0.4220 (5) | −0.1148 (4) | −0.5048 (8) | 0.0258 (12) | 0.5 |
Na2 | −0.6741 (7) | 0.0000 | −0.4195 (11) | 0.0217 (16) | 0.5 |
Na31 | −0.084 (3) | 0.0000 | 0.469 (3) | 0.017 (2)* | 0.229 (19) |
Na32 | −0.036 (2) | 0.0000 | 0.487 (2) | 0.017 (2)* | 0.271 (19) |
O1 | −0.0101 (4) | 0.0937 (3) | 0.2026 (6) | 0.0090 (8) | |
O2 | −0.3346 (4) | 0.0895 (3) | 0.0802 (6) | 0.0127 (8) | |
O3 | −0.0063 (4) | 0.2670 (3) | 0.2696 (6) | 0.0100 (8) | |
O4 | 0.1921 (4) | 0.2070 (3) | 0.1327 (6) | 0.0111 (8) | |
O5 | −0.4356 (6) | 0.0000 | −0.2789 (10) | 0.0202 (14) | |
O6 | 0.1900 (4) | 0.1511 (3) | 0.5228 (6) | 0.0134 (9) | |
O7 | −0.1813 (6) | 0.0000 | −0.1116 (10) | 0.0141 (13) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Co1 | 0.0061 (14) | 0.0053 (15) | 0.0075 (14) | 0.000 | 0.0013 (9) | 0.000 |
Al1 | 0.0061 (14) | 0.0053 (15) | 0.0075 (14) | 0.000 | 0.0013 (9) | 0.000 |
Co2 | 0.0103 (8) | 0.0146 (10) | 0.0102 (9) | 0.000 | 0.0021 (6) | 0.000 |
Al2 | 0.0103 (8) | 0.0146 (10) | 0.0102 (9) | 0.000 | 0.0021 (6) | 0.000 |
Co3 | 0.0065 (3) | 0.0070 (4) | 0.0048 (3) | 0.0004 (3) | 0.0007 (3) | 0.0005 (3) |
As1 | 0.0070 (5) | 0.0067 (6) | 0.0131 (6) | 0.000 | 0.0019 (4) | 0.000 |
P1 | 0.0070 (5) | 0.0067 (6) | 0.0131 (6) | 0.000 | 0.0019 (4) | 0.000 |
As2 | 0.0090 (3) | 0.0115 (3) | 0.0070 (3) | −0.0007 (2) | 0.0010 (2) | 0.0008 (2) |
Na1 | 0.026 (3) | 0.020 (3) | 0.027 (3) | 0.005 (2) | 0.001 (2) | −0.011 (2) |
Na2 | 0.022 (4) | 0.029 (5) | 0.018 (4) | 0.000 | 0.012 (3) | 0.000 |
O1 | 0.0112 (17) | 0.0083 (19) | 0.0072 (18) | −0.0014 (15) | 0.0018 (14) | −0.0006 (16) |
O2 | 0.0149 (19) | 0.011 (2) | 0.0122 (19) | −0.0039 (16) | 0.0043 (15) | −0.0052 (17) |
O3 | 0.0076 (18) | 0.010 (2) | 0.0112 (19) | 0.0023 (16) | 0.0002 (14) | −0.0004 (16) |
O4 | 0.0150 (19) | 0.016 (2) | 0.0041 (18) | −0.0056 (17) | 0.0050 (15) | −0.0040 (16) |
O5 | 0.019 (3) | 0.016 (4) | 0.022 (3) | 0.000 | 0.000 (3) | 0.000 |
O6 | 0.0145 (19) | 0.023 (2) | 0.0022 (17) | 0.0030 (18) | 0.0009 (15) | −0.0017 (16) |
O7 | 0.009 (3) | 0.011 (3) | 0.023 (3) | 0.000 | 0.006 (2) | 0.000 |
Co1—O7i | 1.861 (6) | Na2—Na1ix | 2.086 (8) |
Co1—O7 | 1.861 (6) | Na2—Na1xi | 2.086 (8) |
Co1—O1 | 1.939 (4) | Na2—O5 | 2.443 (10) |
Co1—O1i | 1.939 (4) | Na2—Na31xii | 2.49 (3) |
Co1—O1ii | 1.939 (4) | Na2—O5ix | 2.572 (10) |
Co1—O1iii | 1.939 (4) | Na2—O2iv | 2.584 (7) |
Co2—O2iv | 1.999 (4) | Na2—O2xii | 2.584 (7) |
Co2—O2 | 1.999 (4) | Na2—O6xiii | 2.598 (6) |
Co2—O3v | 2.075 (4) | Na2—O6xiv | 2.598 (6) |
Co2—O3vi | 2.075 (4) | Na2—Na32xii | 2.98 (2) |
Co3—O6vii | 2.054 (4) | Na31—Na32xv | 1.23 (5) |
Co3—O2 | 2.064 (4) | Na31—Na31xv | 1.72 (6) |
Co3—O4iii | 2.080 (4) | Na31—O6xv | 2.473 (15) |
Co3—O4v | 2.092 (4) | Na31—O6vii | 2.473 (15) |
Co3—O1 | 2.171 (4) | Na31—Na2xii | 2.49 (3) |
Co3—O3 | 2.181 (4) | Na31—O1 | 2.524 (17) |
As1—O5 | 1.586 (6) | Na31—O1ii | 2.524 (17) |
As1—O7 | 1.621 (6) | Na31—O1vii | 2.536 (17) |
As1—O2ii | 1.642 (4) | Na31—O1xv | 2.536 (17) |
As1—O2 | 1.642 (4) | Na32—Na32xv | 0.73 (4) |
As2—O6 | 1.637 (4) | Na32—Na31xv | 1.23 (5) |
As2—O4 | 1.662 (4) | Na32—O1vii | 2.408 (13) |
As2—O3 | 1.680 (4) | Na32—O1xv | 2.408 (13) |
As2—O1 | 1.695 (4) | Na32—O1 | 2.407 (13) |
Na1—O5 | 2.276 (7) | Na32—O1ii | 2.407 (13) |
Na1—O3viii | 2.298 (7) | Na32—O6xv | 2.727 (14) |
Na1—O5ix | 2.441 (7) | Na32—O6vii | 2.727 (14) |
Na1—O6i | 2.545 (7) | Na32—Na2xii | 2.98 (2) |
Na1—O3x | 2.572 (8) | ||
O7i—Co1—O7 | 180.0 | O2iv—Co2—O3vi | 105.15 (15) |
O7i—Co1—O1 | 88.09 (17) | O2—Co2—O3vi | 105.29 (15) |
O7—Co1—O1 | 91.91 (17) | O3v—Co2—O3vi | 121.5 (2) |
O7i—Co1—O1i | 91.91 (17) | O6vii—Co3—O2 | 86.29 (16) |
O7—Co1—O1i | 88.09 (17) | O6vii—Co3—O4iii | 173.90 (16) |
O1—Co1—O1i | 180.0 | O2—Co3—O4iii | 88.41 (16) |
O7i—Co1—O1ii | 88.09 (17) | O6vii—Co3—O4v | 96.19 (16) |
O7—Co1—O1ii | 91.91 (17) | O2—Co3—O4v | 91.84 (17) |
O1—Co1—O1ii | 89.4 (2) | O4iii—Co3—O4v | 80.95 (17) |
O1i—Co1—O1ii | 90.6 (2) | O6vii—Co3—O1 | 93.80 (16) |
O7i—Co1—O1iii | 91.91 (17) | O2—Co3—O1 | 102.77 (16) |
O7—Co1—O1iii | 88.09 (17) | O4iii—Co3—O1 | 90.31 (15) |
O1—Co1—O1iii | 90.6 (2) | O4v—Co3—O1 | 162.79 (16) |
O1i—Co1—O1iii | 89.4 (2) | O6vii—Co3—O3 | 96.40 (16) |
O1ii—Co1—O1iii | 180.0 (3) | O2—Co3—O3 | 174.29 (16) |
O2iv—Co2—O2 | 115.1 (3) | O4iii—Co3—O3 | 89.15 (16) |
O2iv—Co2—O3v | 105.29 (15) | O4v—Co3—O3 | 92.87 (16) |
O2—Co2—O3v | 105.15 (15) | O1—Co3—O3 | 72.08 (15) |
Symmetry codes: (i) −x, −y, −z; (ii) x, −y, z; (iii) −x, y, −z; (iv) −x−1, y, −z; (v) x−1/2, −y+1/2, z; (vi) −x−1/2, −y+1/2, −z; (vii) −x, y, −z+1; (viii) x−1/2, y−1/2, z−1; (ix) −x−1, −y, −z−1; (x) −x−1/2, y−1/2, −z; (xi) −x−1, y, −z−1; (xii) −x−1, −y, −z; (xiii) x−1, −y, z−1; (xiv) x−1, y, z−1; (xv) −x, −y, −z+1. |
Cation | q(i)·sofi | Vi | Qi | CNi | ECoNi |
MA | 2.81 | 2.97 | 2.91 | 6 | 5.92 |
MB | 1.61 | 1.31 | 1.58 | 4 | 3.95 |
Co3 | 2.00 | 2.05 | 1.99 | 6 | 5.88 |
MC | 5.00 | 5.21 | 5.00 | 4 | 3.97 |
As2 | 5.00 | 5 | 5.09 | 4 | 3.98 |
Na1 | 0.50 | 0.51 | 0.49 | 5 | 4.53 |
Na2 | 0.50 | 0.52 | 0.49 | 7 | 6.18 |
Na31 | 0.23 | 0.23 | 0.23 | 7 | 6.06 |
Na32 | 0.27 | 0.28 | 0.27 | 6 | 5.31 |
Notes: MA = Co0.189Al0.811; MB = Co0.605Al0.135□0.260; Mc = As0.65P0.35; q is the formal oxidation number; sof is the site-occupation factor; MAPD = 1% [the mean absolute percentage deviation MAPD measures of the agreement between q and Q; for more information, see Nespolo (2016)]. |
Acknowledgements
The authors are grateful to Professor M. F. Zid, Université Tunis El Manar, Faculté des Sciences, for the X-ray data and to Professor M. Nespolo, Kyoto University, Faculty of Sciences, for fruitful discussions.
References
Adams, S. (2003). softBV. University of Göttingen, Germany. https://kristall.uni-mki. gwdg. de/softBV/. Google Scholar
Ben Smail, R., Driss, A. & Jouini, T. (1999). Acta Cryst. C55, 284–286. Web of Science CrossRef CAS IUCr Journals Google Scholar
Bontchev, R. P. & Sevov, S. C. (1999). J. Mater. Chem. 9, 2679–2682. Web of Science CrossRef CAS Google Scholar
Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Brown, I. D. (2002). The Chemical Bond in Inorganic Chemistry – The Bond Valence Model. IUCr Monographs on Crystallography, 12. Oxford University Press. Google Scholar
Chen, J., Xu, R., Xu, Y. & Qiu, J. (1990). J. Chem. Soc. Dalton Trans. pp. 3319–3323. CrossRef Web of Science Google Scholar
Duisenberg, A. J. M. (1992). J. Appl. Cryst. 25, 92–96. CrossRef CAS Web of Science IUCr Journals Google Scholar
Eon, J.-G. & Nespolo, M. (2015). Acta Cryst. B71, 34–47. Web of Science CrossRef IUCr Journals Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany. Google Scholar
Kobashi, D., Kohara, S., Yamakawa, J. & Kawahara, A. (1998). Acta Cryst. C54, 7–9. Web of Science CrossRef CAS IUCr Journals Google Scholar
Li, J., Yu, J. & Xu, R. (2012). Proc. R. Soc. A, 468, 1955–1967. Web of Science CrossRef CAS Google Scholar
Macíček, J. & Yordanov, A. (1992). J. Appl. Cryst. 25, 73–80. CrossRef Web of Science IUCr Journals Google Scholar
Marzouki, R., Guesmi, A. & Driss, A. (2010). Acta Cryst. C66, i95–i98. Web of Science CrossRef IUCr Journals Google Scholar
Marzouki, R., Guesmi, A., Zid, M. F. & Driss, A. (2013). J. Inorg. Chem. pp. 9–16. Google Scholar
Moring, J. & Kostiner, E. (1986). J. Solid State Chem. 62, 105–111. CrossRef CAS Web of Science Google Scholar
Nespolo, M. (2015). CHARDI-2015. https://www.crystallography.fr/chardi. Google Scholar
Nespolo, M. (2016). Acta Cryst. B72, 51–66. Web of Science CrossRef IUCr Journals Google Scholar
North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359. CrossRef IUCr Journals Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.