Synthesis and structure of poly[hydroxonium [μ4-bromido-tetra-μ3-bromido-diplumbate(II)]]

Kreiman, D.S.; Kucheriv, O.I.; Stoica, A.-C.; Malinkin, S.O.; Gural'skiy, I.A.

doi:10.1107/S2056989026011291

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Volume 82| Part 12| December 2026|

https://doi.org/10.1107/S2056989026011291

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Synthesis and structure of poly[hydroxonium [μ₄-bromido-tetra-μ₃-bromido-diplumbate(II)]]

Danylo S. Kreiman,^a ^* Olesia I. Kucheriv,^a Alexandru-Constantin Stoica,^b Sergey O. Malinkin ^a and Il'ya A. Gural'skiy ^a

^aDepartment of Chemistry, Taras Shevchenko National University of Kyiv, Volodymyrska st. 64/13, 01601 Kyiv, Ukraine, and ^bDepartment of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania
^*Correspondence e-mail: [email protected]

Edited by M. Weil, Vienna University of Technology, Austria (Received 8 October 2026; accepted 29 October 2026; online 6 November 2026)

The title compound, {(H₃O)[Pb₂Br₅]}_n, crystallizes in the tetragonal space group I4/mcm. The asymmetric unit comprises one Pb, two Br and one O sites with site symmetry m.2m, 4/m.., ..m and 422, respectively. Bromide ions link the Pb^II atoms to form a two-periodic Pb₂Br₅⁻ anion extending parallel to the ab plane, whilst hydroxonium cations are embedded between neighbouring inorganic layers. Although the hydrogen positions of the hydroxonium cation could not be determined, close O⋯Br contacts suggest possible O—H⋯Br hydrogen-bonding interactions between cations and the anionic layers.

Keywords: hydronium bromidoplumbate(II); lead(II) bromide; two-periodic network; tetragonal crystal structure; Pb—Br coordination; disorder.

CCDC reference: 2599077

1. Chemical context

Lead(II) halide and halidoplumbate(II) compounds display various coordination environments and structural connectivities, both of which are influenced by the stereochemical activity of the Pb^II 6s² lone pair and by the terminal or bridging character of the halido ligands (Shimoni-Livny et al., 1998 ; Mitzi, 2001 ). Lead(II) halides are widely used as precursors for hybrid lead-halide perovskites. The latter have attracted considerable interest due to their semiconducting properties and potential applications in photovoltaics and optoelectronics (Yuan et al., 2025 ; Kucheriv et al., 2023 , 2025 ). The chemistry of halidoplumbate species in solution is also central to the formation of lead-halide perovskites. Studies of lead-halide precursor solutions and solvent-dependent phase formation highlight the importance of halidoplumbate speciation and the coordination environment of Pb^II (Sharenko et al., 2017 ). Hydroxonium ions can exhibit different hydrogen-bonding arrangements in crystalline solids, with their local structure influenced by interactions with the surrounding atoms (Bernal, 2006 ).

In this paper, the crystal structure of the title compound, (H₃O)Pb₂Br₅, (I), containing a two-periodic Pb–Br network, is reported.

2. Structural commentary

The asymmetric unit of (I) comprises four sites, Pb1, Br1, Br2 and O1. They occupy the special Wyckoff positiosn 8 h, 4 c, 16 l and 4 a, with site symmetry m.2m, 4/m.., ..m and 422, respectively, in the tetragonal space group I4/mcm. The asymmetric unit, together with selected symmetry-generated bromide ions that complete the local environment of Pb1, is shown in Fig. 1. The Pb1 atom is eight-coordinated by bromide ions, with Pb1—Br2 and Pb1—Br1 distances of 2.8863 (10)/3.3470 (9) and 3.1287 (2) Å, respectively. The Br—Pb1—Br bond angles range from 66.989 (2)° for Br2( $[{3\over 2}]$ − x, $[{1\over 2}]$ + y, 1 − z)—Pb1—Br2( $[{1\over 2}]$ + x, $[{1\over 2}]$ − y, 1 − z) to 146.5601 (14)° for Br2—Pb1—Br2( $[{1\over 2}]$ + x, $[{1\over 2}]$ − y, 1 − z). A continuous shape-measure analysis using SHAPE 2.1 (Llunell et al., 2013 ) identifies a distorted biaugmented trigonal prism (BTPR-8) as the closest ideal figure for the PbBr₈ coordination polyhedron (CShM = 1.278). Bromide anions link neighbouring Pb^II atoms into a two-periodic Pb₂Br₅⁻ anion extending parallel to the ab plane (Figs. 2, 3).

Figure 1
Fragment of the crystal structure showing the coordination environment of Pb1 in the title compound. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) $[{1\over 2}]$ + y, − $[{1\over 2}]$ + x, 1 − z; (ii) 1 + y, 1 − x, z; (iii) 1 − y, x, z; (iv) $[{3\over 2}]$ − x, $[{1\over 2}]$ + y, 1 − z; (v) $[{1\over 2}]$ + x, $[{1\over 2}]$ − y, 1 − z.]

Figure 2
Fragment of the two-periodic Pb–Br network extending parallel to the ab plane.

Figure 3
View of the crystal packing, showing the Pb₂Br₅⁻ anion layers and the O1-centred hydroxonium ion (small red spheres) between neighbouring layers.

3. Supramolecular features

The O1-centred hydroxonium ion is embedded between two neighbouring Pb–Br layers and forms fourselected O1⋯Br contacts with bromide ions of symmetry-related Pb—Br units (Fig. 4). These contacts involve both the Br1 and Br2 sites. The observed O1⋯Br contacts (Table 1) suggest possible O—H⋯Br hydrogen-bonding interactions between the hydroxonium ion and the anionic layers. However, the hydrogen atom(s) could not be located from the available X-ray data and were therefore omitted from the refinement model. Consequently, the O—H bond orientations and further numerical details of the hydrogen-bonding scheme remain undetermined, and no specific hydrogen-bonding topology is assigned. A view of the overall crystal packing, including the two-periodic Pb–Br networks and the O1-centred hydroxonium ion, is shown in Fig. 3.

Table 1
Selected interatomic distances (Å)

O1⋯Br1ⁱ	3.5848 (3)	O1⋯Br2ⁱⁱ	3.5604 (1)
O1⋯Br2	3.5604 (1)	O1⋯Br2ⁱⁱⁱ	3.5604 (1)
Symmetry codes: (i) $[x-{\script{1\over 2}}, y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) $[-x+1, y, -z+{\script{1\over 2}}]$ ; (iii) $[x, -y+1, -z+{\script{1\over 2}}]$ .

Figure 4
Local environment of the O1-centred hydroxonium ion, showing four selected O1⋯Br contacts with bromide ions of neighbouring Pb–Br layers. Dashed lines indicate O1⋯Br contacts associated with possible O—H⋯Br hydrogen-bonding; hydrogen atom positions remain undetermined. [Symmetry codes: (i) 1 − x, y, $[{1\over 2}]$ − z; (ii) x − $[{1\over 2}]$ , y + $[{1\over 2}]$ , z - 1/2; (iii) x, 1 − y, $[{1\over 2}]$ − z.]

4. Database survey

A search of the Crystallography Open Database (COD; Gražulis et al., 2012 ) identified related Pb^II bromide compounds, of which two were selected for structural comparison: the hydrated lead(II) bromide phase 3PbBr₂·2H₂O (Liu et al., 2018 ) and the oxyhydroxybromide Pb₂OOHBr (Kunisawa et al., 2026 ). The former contains eight-coordinate Pb^II atoms with PbBr₈ or PbBr₇O coordination environments, whereas the latter contains PbBr₄O₄ coordination polyhedra within a Pb–O–Br framework.

5. Synthesis and crystallization

Lead(II) bromide (50 mg, 0.136 mmol) was dissolved in concentrated hydrobromic acid (0.5 ml). After 2 days, light-yellow single crystals suitable for single-crystal X-ray diffraction were formed. They were stored in the mother liquor prior to measurement.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. Due to the site symmetry (422) of the oxygen atom, the hydrogen-atom positions of the hydroxonium cation are orientationally disordered. This fact, combined with the high absorption coefficient of (I), has made it impossible to determine the relevant H positions from difference-Fourier syntheses. Therefore, they were not included in the final model; the contribution from the H atoms is accounted for in the molecular weight given in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	(H₃O)[Pb₂Br₅]
M_r	832.95
Crystal system, space group	Tetragonal, I4/mcm
Temperature (K)	100
a, c (Å)	8.3948 (4), 14.3392 (10)
V (Å³)	1010.52 (12)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	52.98
Crystal size (mm)	0.20 × 0.17 × 0.06

Data collection
Diffractometer	XtaLAB Synergy, Dualflex, HyPix
Absorption correction	Analytical [CrysAlis PRO (Rigaku OD, 2024 ), based on expressions derived by Clark & Reid, 1995 ]
T_min, T_max	0.011, 0.094
No. of measured, independent and observed [I > 2σ(I)] reflections	1765, 368, 317
R_int	0.048
(sin θ/λ)_max (Å⁻¹)	0.699

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.028, 0.075, 1.09
No. of reflections	368
No. of parameters	16
H-atom treatment	H-atom parameters not defined
Δρ_max, Δρ_min (e Å⁻³)	2.31, −1.59
Computer programs: CrysAlis PRO (Rigaku OD, 2024), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ), OLEX2 (Dolomanov et al., 2009 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 2599077

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989026011291/wm5818sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989026011291/wm5818Isup2.hkl

checkCIF report

Computing details top

Poly[hydroxonium [µ₄-bromido-tetra-µ₃-bromido-diplumbate(II)]] top

Crystal data top

(H₃O)[Pb₂Br₅]	D_x = 5.475 Mg m⁻³
M_r = 832.95	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I4/mcm	Cell parameters from 1179 reflections
a = 8.3948 (4) Å	θ = 2.8–29.7°
c = 14.3392 (10) Å	µ = 52.98 mm⁻¹
V = 1010.52 (12) Å³	T = 100 K
Z = 4	Plate, light yellow
F(000) = 1400	0.20 × 0.17 × 0.06 mm

Data collection top

XtaLAB Synergy, Dualflex, HyPix diffractometer	368 independent reflections
Radiation source: micro-focus sealed X-ray tube, PhotonJet (Mo) X-ray Source	317 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.048
Detector resolution: 10.0000 pixels mm^-1	θ_max = 29.8°, θ_min = 2.8°
ω scans	h = −11→11
Absorption correction: analytical [CrysAlisPro (Rigaku OD, 2024), based on expressions derived by Clark & Reid, 1995]	k = −10→7
T_min = 0.011, T_max = 0.094	l = −18→13
1765 measured reflections

Refinement top

Refinement on F²	H-atom parameters not defined
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.037P)² + 12.0445P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.028	(Δ/σ)_max = 0.001
wR(F²) = 0.075	Δρ_max = 2.31 e Å⁻³
S = 1.09	Δρ_min = −1.59 e Å⁻³
368 reflections	Extinction correction: SHELXL2018/3 (Sheldrick 2015b), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
16 parameters	Extinction coefficient: 0.00046 (9)
0 restraints

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pb1	0.83338 (4)	0.33338 (4)	0.500000	0.0116 (2)
Br1	1.000000	0.000000	0.500000	0.0102 (4)
Br2	0.65560 (8)	0.15560 (8)	0.36269 (7)	0.0109 (3)
O1	0.500000	0.500000	0.250000	0.030 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pb1	0.0094 (3)	0.0094 (3)	0.0161 (4)	−0.0005 (2)	0.000	0.000
Br1	0.0078 (5)	0.0078 (5)	0.0150 (9)	0.000	0.000	0.000
Br2	0.0105 (4)	0.0105 (4)	0.0117 (5)	−0.0014 (4)	−0.0010 (3)	−0.0010 (3)
O1	0.034 (6)	0.034 (6)	0.023 (8)	0.000	0.000	0.000

Geometric parameters (Å, º) top

Pb1—Br1	3.1287 (2)	Pb1—Br2ⁱⁱ	2.8863 (10)
Pb1—Br1ⁱ	3.1287 (2)	Pb1—Br2	2.8863 (10)

O1···Br1ⁱⁱⁱ	3.5848 (3)	O1···Br2^iv	3.5604 (1)
O1···Br2	3.5604 (1)	O1···Br2^v	3.5604 (1)

Br1—Pb1—Br1ⁱ	143.113 (17)	Pb1—Br1—Pb1^vi	180.0
Br2ⁱⁱ—Pb1—Br1ⁱ	76.624 (9)	Pb1^vii—Br1—Pb1^viii	180.0
Br2ⁱⁱ—Pb1—Br1	76.624 (9)	Pb1—Br1—Pb1^vii	90.0
Br2—Pb1—Br1	76.624 (9)	Pb1^vii—Br1—Pb1^vi	90.0
Br2—Pb1—Br1ⁱ	76.624 (9)	Pb1^viii—Br1—Pb1^vi	90.0
Br2ⁱⁱ—Pb1—Br2	86.02 (4)	Pb1—Br1—Pb1^viii	90.0

Symmetry codes: (i) −x+3/2, y+1/2, −z+1; (ii) x, y, −z+1; (iii) x−1/2, y+1/2, z−1/2; (iv) −x+1, y, −z+1/2; (v) x, −y+1, −z+1/2; (vi) −x+2, −y, −z+1; (vii) y+1, −x+1, −z+1; (viii) −y+1, x−1, z.

Acknowledgements

The authors are grateful to the FAIRE programme provided by the Cambridge Crystallographic Data Centre (CCDC) for the opportunity to use the Cambridge Structural Database (CSD) and associated software.

Funding information

Funding for this research was provided by: Ministry of Education and Science of Ukraine (grant Nos. 24BF037-01M and 24BF037-02).

References

Bernal, I. (2006). C. R. Chim. 9, 1454–1466. Web of Science CrossRef CAS Google Scholar
Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887–897. CrossRef CAS Web of Science IUCr Journals Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Gražulis, S., Daškevič, A., Merkys, A., Chateigner, D., Lutterotti, L., Quirós, M., Serebryanaya, N. R., Moeck, P., Downs, R. T. & Le Bail, A. (2012). Nucleic Acids Res. 40, D420–D427. Web of Science PubMed Google Scholar
Kucheriv, O. I., Haleliuk, D. A., Shova, S. & Gural'skiy, I. A. (2025). Dalton Trans. 54, 1618–1624. CSD CrossRef CAS PubMed Google Scholar
Kucheriv, O. I., Sirenko, V. Y., Petrosova, H. R., Pavlenko, V. A., Shova, S. & Gural'skiy, I. A. (2023). Inorg. Chem. Front. 10, 6953–6963. Web of Science CSD CrossRef CAS Google Scholar
Kunisawa, H., Yamaura, J.-I. & Nomura, T. (2026). IUCrData 11, x260790. Google Scholar
Liu, M., Zhao, J., Luo, Z., Sun, Z., Pan, N., Ding, H. & Wang, X. (2018). Chem. Mater. 30, 5846–5852. CSD CrossRef ICSD CAS Google Scholar
Llunell, M., Casanova, D., Cirera, J., Alemany, P. & Alvarez, S. (2013). SHAPE. Version 2.1. Universitat de Barcelona, Barcelona, Spain. Google Scholar
Mitzi, D. B. (2001). J. Chem. Soc. Dalton Trans. pp. 1–12. Web of Science CrossRef Google Scholar
Rigaku OD (2024). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England. Google Scholar
Sharenko, A., Mackeen, C., Jewell, L., Bridges, F. & Toney, M. F. (2017). Chem. Mater. 29, 1315–1320. CrossRef CAS Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Shimoni-Livny, L., Glusker, J. P. & Bock, C. W. (1998). Inorg. Chem. 37, 1853–1867. Web of Science CrossRef CAS Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Yuan, L., Xue, Q., Wang, F., Li, N., Waterhouse, G. I. N., Brabec, C. J., Gao, F. & Yan, K. (2025). Chem. Rev. 125, 5057–5162. CrossRef CAS PubMed Google Scholar

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