Room-tem­per­a­ture crystal structures of [CH(NH2)2]3Sb2X9 (X = Br and I)

Bhatt, P.; Liu, Y.; Regoutz, A.; Palgrave, R.G.

doi:10.1107/S2053229626000811

research papers

STRUCTURAL
CHEMISTRY

ISSN: 2053-2296

Volume 82| Part 3| March 2026| Pages 138-143

https://doi.org/10.1107/S2053229626000811

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Room-temperature crystal structures of [CH(NH₂)₂]₃Sb₂X₉ (X = Br and I)

Prajna Bhatt,^a,^b ^* Yuhan Liu,^a,^c Anna Regoutz ^a,^d and Robert G. Palgrave ^a ^*

^aDepartment of Chemistry, University College London, 20 Gordon St, London, WC1H 0AJ, United Kingdom, ^bIstituto Officina dei Materiali (IOM)–CNR, Area Science Park, S.S.14, Km 163.5, Trieste I-34149, Italy, ^cThe Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London, WC1E 7JE, United Kingdom, and ^dDepartment of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, United Kingdom
^*Correspondence e-mail: [email protected], [email protected]

Edited by M. Yousufuddin, University of North Texas at Dallas, USA (Received 18 November 2025; accepted 26 January 2026; online 26 February 2026)

Crystals of formamidinium antimony, halides, FA₃Sb₂X₉ {FA = [CH(NH₂)₂]⁺; X = Br⁻ and I⁻} {or triformamidinium nonahalidodiantimony, (CH₅N₂)₃[Sb₂X₉]}, have been synthesized using a counter diffusion crystal growth (CDCG) method in silica gel and their structures determined from single-crystal X-ray diffraction data. FA₃Sb₂Br₉ belongs to the trigonal space group P3m1, which is known as the Cs₃Bi₂Br₉ structure type, and FA₃Sb₂I₉ belongs to the hexagonal space group P6₃/mmc, called the Cs₃Cr₂Cl₉ structure type. The change of the anion type from bromide to iodide results in the change of the structure type and the connectivity of the Sb—X octahedra. These structures are described and compared to the crystal types known for vacancy-ordered triple-perovskites.

Keywords: halide perovskite; crystallography; counter diffusion crystal growth; CDCG; single crystal; crystal structure; formamidinium; antimony.

CCDC references: 2501007; 2500813

1. Introduction

The A₃B₂X₉ structure, where A is a monovalent cation, B is a trivalent cation and X is a halide, are commonly described as derivatives of the ABX₃ perovskite structure type. In the ABX₃ form, all [BX₆]³⁻ octahedra are corner-sharing and an A₃B₂X₉ compound can be considered similarly, with removal of a third of the B-site cations (Hodgkins et al., 2019 ; Chang et al., 2016 ). As such, these structures are more commonly known as vacancy-ordered triple-perovskites. Typical A₃B₂X₉ compounds are group 15 halides, mostly comprising of bismuth (Bi) and antimony (Sb) B-sites. The triple-perovskites are considered as perovskite derivatives that can similarly be applied in photovoltaic and radiation detection applications as lead-free alternatives (Eperon et al., 2014 ; Hao et al., 2014 ). Due to the optical and electronic properties possessed by these compounds for such applications, materials design approaches also include the formation of compounds with organic monovalent cations. Here, the crystal structure of two organic–inorganic triple-perovskites, namely, FA₃Sb₂X₉ {FA = [CH(NH₂)₂]⁺; X = Br⁻ and I⁻}, are reported.

2. Experimental methods

Single crystals were synthesized using a counter diffusion crystal growth (CDCG) method in silica gel. 27 mmol of Sb₂O₃ (Sigma–Aldrich, 99%) were reacted with excess HX, where X = Br (Sigma–Aldrich, 48 wt%) or I (Sigma–Aldrich, 57 wt%), to produce SbX₃ in an acidic solution. In parallel, a 0.6 M aqueous solution of Na₂SiO₃ (Sigma–Aldrich) was prepared using distilled water. The Na₂SiO₃ solution was added dropwise in the presence of vigorous stirring to SbX₃ in a 1:1 (v/v) ratio to form a SbX₃-based silica gel. The solution was allowed to set in 50 ml tall-form beakers in a low-temperature oven at 29 °C over 24 h. Post gelation, solutions containing 41 mmol of FAX {FA = [CH(NH₂)₂]⁺}, made by dissolving formamidine acetate (Sigma–Aldrich, ≥ 98%) in HX, were added carefully atop the gel using pipettes to avoid disrupting the surface of the gel. The beaker was wrapped with parafilm and placed in an oven. Crystal growth occurred between 2–7 d. FA₃Sb₂Br₉ was isolated in the form of pale-yellow plate-like crystals, while FA₃Sb₂I₉ crystallized in the morphology of red–brown needle-like crystals (Fig. S1).

Powder X-ray diffraction (PXRD) was measured with a Stoe STADI-P X-ray diffractometer in thin foil transmission (Debye–Scherrer geometry) mode equipped with a germanium (111) monochromator and a Dectris Mythen 1K detector, with Cu Kα (λ = 1.5406 Å, using 40 kV and 30 mA) radiation at 298 K. Samples were loaded between two clear acetate sheets and sealed using silicon vacuum grease. Diffraction patterns were collected in a 2θ range from 2 to 70°, with a step size of 0.015° and a scan rate of 5 s per step. Rietveld refinement models (Rietveld, 1966 ) on PXRD data were carried out within the TOPAS-Academic software suite (Version 7; Coelho, 2018 ; Coelho, 2022 ).

Single-crystal X-ray diffraction (SCXRD) was performed using an Agilent SuperNova diffractometer with an Atlas CCD detector. Full spheres of data were collected using 1° scan frames in ω with monochromated Cu or Mo Kα radiation at 295 K. A refinement of the positions of the C, N and H atoms was not carried out because isotropic rotation of the FA cations takes place at room temperature like other organic monovalent cations (Liu et al., 2022 ). The supporting information includes a discussion on the treatment of the FA cation in detail. The experimental details from SCXRD are summarized in Table 1.

Table 1
Experimental details

Experiments were carried out at 295 K using an Agilent SuperNova Dual Source diffractometer with a HyPix-Arc 100 detector. Absorption was corrected for by multi-scan methods (CrysAlis PRO; Rigaku OD, 2022 ). Refinement was on 19 parameters. H-atom parameters were not defined.

	FA₃Sb₂Br₉	FA₃Sb₂I₉
Crystal data
Chemical formula	(CH₅N₂)₃[Sb₂Br₉]	(CH₅N₂)₃[Sb₂I₉]
M_r	998.72	1421.63
Crystal system, space group	Trigonal, P $[\overline{3}]$ m1	Hexagonal, P6₃/mmc
a, b, c (Å)	8.5161 (4), 8.5161 (4), 10.0380 (4)	8.7552 (4), 8.7552 (4), 21.8474 (12)
α, β, γ (°)	90, 90, 120	90, 90, 120
V (Å³)	630.46 (6)	1450.32 (15)
Z	1	2
Radiation type	Cu Kα	Mo Kα
μ (mm⁻¹)	33.54	11.42
Crystal size (mm)	0.19 × 0.15 × 0.04	0.13 × 0.13 × 0.09

Data collection
T_min, T_max	0.061, 1.000	0.263, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	13069, 546, 391	36967, 896, 456
R_int	0.089	0.104
(sin θ/λ)_max (Å⁻¹)	0.631	0.728

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.067, 0.241, 1.14	0.056, 0.242, 1.05
No. of reflections	546	896
No. of restraints	0	1
Δρ_max, Δρ_min (e Å⁻³)	1.11, −1.03	1.24, −0.45
Computer programs: CrysAlis PRO (Rigaku OD, 2022), SHELXT2014 (Sheldrick, 2015a ), SHELXL2025 (Sheldrick, 2015b ), OLEX2 (Dolomanov et al., 2009), VESTA (Momma & Izumi, 2011 ) and OLEX2 (Dolomanov et al., 2009).

All other experimental techniques employed (Raman spectroscopy, X-ray photoelectron spectroscopy and diffuse reflectance spectroscopy) are described in the supporting information.

3. Results and discussion

3.1. Description of structures

3.1.1. Formamidinium antimony bromide, FA₃Sb₂Br₉

FA₃Sb₂Br₉ was found to crystallize in the Cs₃Bi₂Br₉ structure type. Compounds of this crystal type belong to the trigonal space group P $[\overline{3}]$ m1 (Lazarini, 1977 ). The lattice parameters for FA₃Sb₂Br₉ are a = 8.5161 (4), c = 10.0380 (4) Å and V = 630.46 (6) Å³. Similar to most organic–inorganic triple-perovskites, the FA cations possess rotational disorder at room temperature (Bhatt et al., 2025 ), resulting in failed attempts to localize discrete C and N atoms. The solvent-masking routine in OLEX2 was employed (Dolomanov et al., 2009 ) and a void volume of 244 Å³ per unit cell identified (38.7% of the total unit cell). The integrated electron count within this void was found to be 77 electrons. This is in excellent agreement with the 75 electrons expected theoretically for the three FA cations in the unit cell, confirming the existence of FA cations in the compound. In this article, a single C atom was used as a placeholder in the unit cell to represent the FA cation, as discussed in the methods and supporting information.

Common bromide-based vacancy-ordered triple-perovskites that are also known to crystallize in this structure type include MA₃Bi₂Br₉, MA₃Sb₂Br₉ and FA₃Bi₂Br₉ (MA = CH₃NH₃⁺) (Ishihara et al., 1992 ; Tomaszewski, 1994 ; Shen et al., 2020 ). The isostructural Cs₃Bi₂Br₉ was reported to have the Cs and Br atoms in a cubic close-packed arrangement, with the Bi atom occupying one-sixth of the octahedral holes in the crystal structure. The structure of FA₃Sb₂Br₉ can also be considered a `2D form' of a vacancy-ordered triple-perovskite (Chen et al., 2024 ). Here, the corner-sharing [SbBr₆]³⁻ octahedra possess a structural dimensionality such that the octahedra can be described as 2D layers, within which A-site cations are located. For FA₃Sb₂Br₉ visualized in Fig. 1(a), [SbBr₆]³⁻ octahedra (in light brown) generate these 2D layers by sharing three Br atoms with three different neighbouring octahedra.

Figure 1
Representation of FA₃Sb₂Br₉ from this work shown (a) obliquely, (b) down the c axis and (c) down the b axis. Four unit cells are shown, with a black-bordered box around one unit cell. Pink spheres represent Sb, brown spheres represent Br and the light-brown octahedra represent the [SbBr₆]³⁻ coordination environment. A-site atoms are bifurcated by their Wyckoff positions, i.e. green spheres represent C atoms on site 2d between [SbBr₆]³⁻ layers and red spheres reside on site 1a between rings of six [SbBr₆]³⁻ octahedra. C atoms are used in place of the FA ion, as explained in the text. The blue layer in (c) represents the common plane of bromide ions, as explained in the text. The figure was prepared using the VESTA software suite (Version 3; Momma & Izumi, 2011

Within the layer, the corner-sharing octahedra result in the formation of six-connected octahedra `rings' [Fig. 1(b)] where the FA ions reside (red atoms). This is similar to the ABX₃ perovskite structure with the exception of six surrounding B-site octahedra rather than eight (Xia et al., 2020 ). In addition, the FA ions fill spaces between these corner-sharing octahedra 2D layers (green), observed as [SbBr₆]³⁻–FA⁺–[SbBr₆]³⁻ layers along the c axis. The A- and B-site coordination numbers are 12 and 6, respectively, and agree with other compounds that crystallize in this structure type.

This structure has also been described previously as isolated layers formed by [SbBr₆]³⁻ octahedra pointing alternatively up or down with respect to a plane of common halide atoms (Tomaszewski, 1994). Fig. 1(c) shows the orientation of the octahedra alternating in orientation with respect to the layer of bromide ions (displayed with a blue line).

Refined atomic position parameters, selected interatomic distances and bond angles for FA₃Sb₂Br₉ are listed in Table 2. Each [SbBr₆]³⁻ octahedron has three equivalent Sb—Br1 and Sb—Br2 distances of 3.0598 (7) and 2.612 (2) Å, respectively. These are comparable to the distances reported in MA₃Sb₂Br₉, where Sb—Br1 = 3.000 Å and Sb—Br2 = 2.627 Å (Ishihara et al., 1992). Both FA₃Sb₂Br₉ and MA₃Sb₂Br₉ have similar bond angles of Br1—Sb—Br2 (≈177°) and Brx—Sb—Brx (in the range 88–92°), where x is the same number. This difference in the Sb—Br bond lengths and angles within a single octahedron arises from the distortions from the vertex-sharing Br1 halide ions.

Table 2
Atomic position parameters, interatomic distances (Å) and bond angles (°) obtained from the structural solution of SCXRD data collected at 295 K of FA₃Sb₂Br₉

x, y and z are the position parameters of different atoms, and `Occ' is the occupancy of the atom at the determined position. W is the Wyckoff position notation and U is the anisotropic displacement parameter. C atoms are used in place of the FA ion, as explained in the text. Bond distances and angles were determined using the VESTA software suite (Version 3; Momma & Izumi, 2011).

Atom	x	y	z	Occ	W	U
Sb	1/3	2/3	0.31852 (12)	1	2d	0.1112 (8)
Br1	1/2	3/2	1/2	1	3f	0.1457 (11)
Br2	0.6278 (3)	0.81392 (16)	0.17401 (18)	1	6i	0.1709 (12)
C1	2/3	4/3	0.191 (4)	1	2d	0.21 (3)
C2	−3.00000	−1.00000	1/2	1	1b	0.22 (3)

Atoms		Interatomic distance		Atoms		Bond angle
Sb—Br1		3.0598 (7)		Br1—Sb—Br2		177.20 (6)
Sb—Br2		2.6119 (19)		Br1—Sb—Br1		88.18 (3)
Br1—Br2		4.016 (3)		Br2—Sb—Br2		92.14 (8)

When compared to the bismuth compound MA₃Bi₂Br₉, the Sb—Br1 distance of FA₃Sb₂Br₉ is similar to Bi—Br1 (3.054 Å), while Sb—Br2 of FA₃Sb₂Br₉ is smaller than Bi—Br2 (2.772 Å) in MA₃Bi₂Br₉. The six-coordinate ionic radius of Sb³⁺ (0.76 Å) in FA₃Sb₂Br₉ is smaller compared to that of Bi³⁺ (1.03 Å) in MA₃Bi₂Br₉ (Ahrens, 1952 ; Shannon, 1976 ). Antimony compounds are therefore expected to have smaller unit cells and shorter bond lengths compared to bromobismuthates. Smaller B-site ions also mean the [SbBr₆]³⁻ octahedra are expected to have lower angular distortions than [BiBr₆]³⁻. Considering bond angles, there is a stronger distortion of the Br—Bi—Br angles, with Br1—Bi—Br2 being ≈169.3° and Brx—Bi—Brx in the range 84–88°. The angles in the Bi compound are smaller than equivalent octahedral bond angles in FA₃Sb₂Br₉, where Br atoms are arranged around a larger cation (Lazarini, 1977).

The plotted Rietveld refinement of PXRD data (Fig. 2) shows excellent agreement between the Y_obs and Y_calc plots. The commensurate position of the Bragg reflections from SCXRD resolution and the peak positions from PXRD data indicate that the structural resolution is accurate for both single crystals and polycrystalline powders. A goodness-of-fit (GOF) of 1.14 and R_w = 10.319% were achieved.

Figure 2
Rietveld refinement on the PXRD pattern of FA₃Sb₂Br₉ single crystals made by CDCG. Input unit-cell information was taken from the structure resolved from SCXRD data. Y_obs (red) is the collected diffraction pattern, Y_calc (blue) is the calculated pattern from TOPAS-Academic and Y_obs − Y_calc (yellow) is the residual plot. Reflections that are ≥5% of the highest intensity reflection are indexed.

3.1.2. Formamidinium antimony iodide, FA₃Sb₂I₉

FA₃Sb₂I₉ belongs to the hexagonal space group P6₃/mmc at room temperature. This is known as the Cs₃Cr₂Cl₉ structural type wherein FA₃Bi₂I₉, MA₃Sb₂I₉ (MA = CH₃NH₃), Cs₃Sb₂I₉ and Cs₃Bi₂I₉ are known structures of group 15 triple-perovskites (Szklarz et al., 2019 ; Ju et al., 2018 ; Yamada et al., 1997 ; Arakcheeva et al., 1999 ). FA₃Sb₂I₉ has been reported previously at 195 K, also exhibiting the space group P6₃/mmc (Szklarz et al., 2020 ). One way to describe this structure considers the FA cation and I atoms forming close-packed FAI₃ layers, with Sb atoms occupying one-sixth of the total octahedral holes (Arakcheeva et al., 1999). The close packing of the AX layers is hexagonal and the layered structure is comprised of isolated [Sb₂I₉]³⁻ bioctahedra or `dimers' which share a triangular face and three iodide ions. These are illustrated in Fig. 3 as purple polyhedra. As such, this variant of the triple-perovskite is also regarded as a 0D isolated dimer structure. The Sb—Sb axis within each bioctahedron is parallel to the c axis.

Figure 3
Unit-cell representation of FA₃Sb₂I₉ from this work shown obliquely. Green spheres represent Sb, grey spheres represent I and purple bioctahedra represent the [Sb₂I₉]³⁻ coordination environment. C atoms are bifurcated by their Wyckoff positions, i.e. pink spheres represent C atoms on site 4f and brown spheres reside on site 2b. C atoms are used in place of the FA ion, as explained in the text. The figure was prepared using the VESTA software suite (Version 3; Momma & Izumi, 2011

As in the bromide structure, the FA cations were found to be highly disordered. A total void volume of 541 Å³ (37.3% of the total unit cell) was identified, containing 105 electrons per unit cell, which corresponds to the region occupied by the disordered cations. While this is lower than the ideal count for six FA cations (150 electrons), it is consistent with the presence of rotationally disordered organic species that cannot be resolved into discrete atomic positions. When a single C atom in the void replaces one FA cation, a similar R factor is achieved. Thus, the FA cations in the unit cell are represented by C atoms.

The C1 position of the cation (pink) at Wyckoff position 4f is in the same plane of each dimer and its coordination can be described as identical layered stacking of the iodide ions with a hexagonal coordination (six) on either side of the FA cation (Stranger et al., 1978 ). Additionally, C2, in brown, appears displaced from the plane of the terminal iodide ions of the bioctahedra, also resulting in a cuboctahedral coordinated FAI₁₂ environment.

The atomic positions, bioctahedral bond lengths and angles of FA₃Sb₂I₉ are summarized in Table 3. For FA₃Sb₂I₉, the Sb—I1 bond length is 3.2323 (12) Å, while Sb—I2 is 2.8758 (13) Å. These align well with the Sb—I bond lengths of the structure that Szklarz et al., (2020) collected on FA₃Sb₂I₉ at 195 K, i.e. 3.213 and 2.881 Å. These values are also similar to those in the bioctahedra of A₃Sb₂I₉ (A = Cs or MA), with bond lengths of 3.198 and 2.870 Å for A = Cs, and 3.213 and 2.887 Å for A = MA (Chabot & Parthé, 1978 ; Ju et al., 2018). These confirm crystallization of A₃Sb₂I₉ in a Cs₃Cr₂Cl₉-type crystal structure at room temperature. Bond angles in the range 83–94° for terminal I—Sb—I, and around 172.9° for bridging I—Sb—I are similarly comparable to literature values. For MA₃Sb₂I₉, the bond angles are in the range 84–91° for terminal I—Sb—I, and around 173.8° for bridging I—Sb—I. These angles diverge from 90 and 180°, respectively, indicating the distortion of the bioctahedral units as a result of face-sharing in the ab plane.

Table 3
Atomic position parameters, interatomic distances (Å) and bond angles (°) obtained from the structural solution of SCXRD data collected at 295 K of FA₃Sb₂I₉

See Table 2 for definitions.

Atom	x	y	z	Occ	W	U
Sb	2/3	1/3	0.34482 (6)	1	4f	0.0810 (6)
I1	0.50288 (8)	0.49712 (8)	1/2	1	6h	0.1312 (7)
I2	0.82610 (9)	0.65220 (18)	0.41593 (6)	1	12k	0.1312 (7)
C1	1/3	2/3	0.405 (4)	1	4f	0.21 (2)
C2	1.00000	1.00000	1/4	1	2b	0.20 (3)

Atoms		Interatomic distance		Atoms		Bond angle
Sb—I1		3.2323 (12)		I1—Sb—I2		172.94 (5)
Sb—I2		2.8758 (13)		I1—Sb—I1		83.41 (3)
I1—I2		4.3762 (15)		I2—Sb—I2		93.50 (5)

The Rietveld refinement of PXRD data in Fig. 4 is based on the SCXRD structure and shows good agreement with the PXRD data collected, fortifying the triple-perovskite structure at room temperature. A goodness-of-fit (GOF) of 1.11 and R_w = 9.217% were achieved.

Figure 4
Rietveld refinement on the PXRD pattern of FA₃Sb₂I₉ single crystals made by CDCG. Input unit-cell information was taken from the structure resolved from SCXRD data. Y_obs (red) is the collected diffraction pattern, Y_calc (blue) is the calculated pattern from TOPAS-Academic and Y_obs − Y_calc (yellow) is the residual plot. Reflections that are ≥5% of the highest intensity reflection are indexed.

X-ray photoelectron spectroscopy (XPS) was employed for the identification of chemical environments and elemental quantification to verify the formation of A₃B₂X₉ compounds; see Fig. S2 and Tables S1 and S2 in the supporting information. The elemental quantification in Table S2 matches closely the expected A₃B₂X₉ composition. From the survey spectra [Fig. S2(a)], core lines from the expected elements for FA₃Sb₂X₉ are observed, in addition to Si from contamination during sample plating. The supporting information also reports the absolute binding energy (BE) values of the core levels in Table S1, due to issues noted for the application of charge compensation (such as C 1s) for organic–inorganic compounds (Jia et al., 2023 ). From the XPS spectra, the relative BE (ΔBE) between the N1s core line (from the FA cation, appearing around 400 eV) and the Sb 3d_5/2 core line (appearing around 530 eV) is 130.2 eV for FA₃Sb₂Br₉ and 129.6 eV for FA₃Sb₂I₉. The values are within 1 eV of each other, indicating the presence of similar A- and B-site chemical environments, regardless of the halide. The reduction in the ΔBE(Sb 3d_5/2—N1s) values from FA₃Sb₂Br₉ to FA₃Sb₂I₉ may be due to a shift of Sb3 d_5/2 to lower BE and/or a shift of N 1s to higher BE. A shift of a core level to lower (higher) BEs is indicative of higher (lower) charge densities around the atom (Greczynski & Hultman, 2022 ). Given the lower electronegativity of iodine, it is reasonable to assume that the Sb in FA₃Sb₂I₉ has greater charge density than Sb in FA₃Sb₂Br₉, which then explains the change in ΔBE(Sb 3d_5/2—N 1s).

4. Conclusions and future perspectives

Single crystals of FA₃Sb₂X₉ (X = Br⁻ and I⁻) were grown successfully by counter diffusion crystal growth in silica gel, and their room-temperature structures identified. FA₃Sb₂Br₉ crystallizes in the Cs₃Bi₂Br₉ structure type, while FA₃Sb₂I₉ belongs to the Cs₃Cr₂Cl₉ structure type. Both structures were compared to known compounds of group 15 triple-perovskites. Further work to understand these crystal structures may include the study of temperature-dependent phase transitions, in particular to resolve the organic A-site positions and to gain further insights on the stability of these compounds.

5. Related literature

The following references are cited in the supporting information for this article: Kalha et al. (2020 ); McCall et al. (2017 ); Scofield (1973 ); Scholz et al. (2018 ); Teterin et al. (2008 ); Wolstenholme (2008 ).

Supporting information

CCDC references: 2501007; 2500813

Link https://doi.org/10.5281/zenodo.17578603
Data for this article, including all processed data of the figures, are available at Zenodo in Origin format

Crystal structure: contains datablocks I, II, global. DOI: https://doi.org/10.1107/S2053229626000811/yd3067sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2053229626000811/yd3067Isup2.hkl

Structure factors: contains datablock II. DOI: https://doi.org/10.1107/S2053229626000811/yd3067IIsup3.hkl

Treatment of the disordered formamidinium cation in single crystal refinement and additional experimental methods. DOI: https://doi.org/10.1107/S2053229626000811/yd3067sup4.pdf

Computing details top

Triformamidinium nonabromidodiantimony (I) top

Crystal data top

(CH₅N₂)₃[Sb₂Br₉]	D_x = 2.630 Mg m⁻³
M_r = 998.72	Cu Kα radiation, λ = 1.54184 Å
Trigonal, P3m1	Cell parameters from 2382 reflections
a = 8.5161 (4) Å	θ = 4.4–52.7°
c = 10.0380 (4) Å	µ = 33.54 mm⁻¹
V = 630.46 (6) Å³	T = 295 K
Z = 1	Plate, clear yellowish yellow
F(000) = 435	0.19 × 0.15 × 0.04 mm

Data collection top

Agilent SuperNova Dual Source diffractometer with a HyPix-Arc 100 detector	546 independent reflections
Radiation source: micro-focus sealed X-ray tube, SuperNova (Cu) X-ray Source	391 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.089
Detector resolution: 10.0000 pixels mm^-1	θ_max = 76.8°, θ_min = 4.4°
ω scans	h = −10→10
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2022)	k = −10→9
T_min = 0.061, T_max = 1.000	l = −12→12
13069 measured reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Primary atom site location: dual
R[F² > 2σ(F²)] = 0.067	H-atom parameters not defined
wR(F²) = 0.241	w = 1/[σ²(F_o²) + (0.1581P)²] where P = (F_o² + 2F_c²)/3
S = 1.14	(Δ/σ)_max < 0.001
546 reflections	Δρ_max = 1.11 e Å⁻³
19 parameters	Δρ_min = −1.03 e Å⁻³

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. Data was processed with the CrysAlis PRO software suite, and the structure was solved with SHELXT (Sheldrick, 2015a) and refined with SHELXL (Sheldrick, 2015b) within the OLEX2 software suite (Dolomanov et al., 2009).

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

	x	y	z	U_iso*/U_eq
Sb1	0.3333	0.6667	0.31852 (12)	0.1112 (8)
Br1	0.5000	1.5000	0.5000	0.1457 (11)
Br2	0.6278 (3)	0.81392 (16)	0.17401 (18)	0.1710 (12)
C1	0.6667	1.3333	0.191 (4)	0.21 (3)
C2	0.0000	0.0000	0.5000	0.22 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Sb1	0.1230 (10)	0.1230 (10)	0.0876 (9)	0.0615 (5)	0.000	0.000
Br1	0.1652 (19)	0.1652 (19)	0.1377 (19)	0.1057 (19)	−0.0055 (6)	0.0055 (6)
Br2	0.1663 (18)	0.205 (2)	0.1289 (15)	0.0832 (9)	0.0485 (12)	0.0242 (6)
C1	0.20 (3)	0.20 (3)	0.24 (7)	0.101 (17)	0.000	0.000
C2	0.24 (5)	0.24 (5)	0.18 (6)	0.12 (2)	0.000	0.000

Geometric parameters (Å, º) top

Sb1—Sb1ⁱ	6.1195 (14)	Sb1—Br2^viii	2.6119 (19)
Sb1—Sb1ⁱⁱ	6.1195 (14)	Sb1—Br2^ix	2.6119 (19)
Sb1—Sb1ⁱⁱⁱ	6.1195 (14)	Sb1—Br2	2.612 (2)
Sb1—Br1^iv	3.0598 (7)	Br1—Sb1^x	3.0597 (7)
Sb1—Br1^v	10.8696 (5)	Br1—Sb1ⁱⁱ	10.8696 (5)
Sb1—Br1^vi	3.0598 (7)	Br1—Sb1ⁱ	3.0598 (7)
Sb1—Br1^vii	3.0598 (7)

Sb1ⁱⁱⁱ—Sb1—Sb1ⁱⁱ	88.19 (3)	Br2—Sb1—Sb1ⁱ	89.80 (4)
Sb1ⁱ—Sb1—Sb1ⁱⁱ	88.18 (3)	Br2—Sb1—Sb1ⁱⁱⁱ	177.20 (6)
Sb1ⁱⁱⁱ—Sb1—Sb1ⁱ	88.18 (3)	Br2—Sb1—Sb1ⁱⁱ	89.80 (4)
Sb1ⁱⁱ—Sb1—Br1^v	89.489 (7)	Br2^ix—Sb1—Sb1ⁱⁱ	89.80 (4)
Sb1ⁱⁱⁱ—Sb1—Br1^v	122.428 (18)	Br2^viii—Sb1—Sb1ⁱⁱ	177.20 (6)
Sb1ⁱ—Sb1—Br1^v	34.243 (8)	Br2^ix—Sb1—Sb1ⁱ	177.20 (6)
Br1^vii—Sb1—Sb1ⁱⁱⁱ	88.18 (3)	Br2^ix—Sb1—Br1^vii	177.20 (6)
Br1^vi—Sb1—Sb1ⁱⁱ	0.0	Br2—Sb1—Br1^vi	89.80 (4)
Br1^vi—Sb1—Sb1ⁱⁱⁱ	88.19 (3)	Br2—Sb1—Br1^v	55.58 (4)
Br1^iv—Sb1—Sb1ⁱⁱⁱ	0.0	Br2^viii—Sb1—Br1^iv	89.80 (4)
Br1^vii—Sb1—Sb1ⁱ	0.0	Br2^viii—Sb1—Br1^vii	89.80 (4)
Br1^iv—Sb1—Sb1ⁱⁱ	88.18 (3)	Br2—Sb1—Br1^iv	177.20 (6)
Br1^iv—Sb1—Sb1ⁱ	88.18 (3)	Br2—Sb1—Br1^vii	89.80 (4)
Br1^vi—Sb1—Sb1ⁱ	88.18 (3)	Br2^ix—Sb1—Br1^iv	89.80 (4)
Br1^vii—Sb1—Sb1ⁱⁱ	88.18 (3)	Br2^ix—Sb1—Br1^vi	89.80 (4)
Br1^vii—Sb1—Br1^vi	88.18 (3)	Br2^viii—Sb1—Br1^vi	177.20 (6)
Br1^vii—Sb1—Br1^iv	88.18 (3)	Br2^viii—Sb1—Br1^v	89.945 (11)
Br1^vi—Sb1—Br1^v	89.489 (7)	Br2^ix—Sb1—Br1^v	147.72 (4)
Br1^vii—Sb1—Br1^v	34.243 (8)	Br2^viii—Sb1—Br2^ix	92.14 (8)
Br1^iv—Sb1—Br1^v	122.428 (18)	Br2—Sb1—Br2^ix	92.14 (8)
Br1^iv—Sb1—Br1^vi	88.18 (3)	Br2^viii—Sb1—Br2	92.14 (8)
Br2^viii—Sb1—Sb1ⁱ	89.80 (4)	Sb1^x—Br1—Sb1ⁱ	180.00 (4)
Br2^viii—Sb1—Sb1ⁱⁱⁱ	89.80 (4)	Sb1ⁱ—Br1—Sb1ⁱⁱ	34.243 (8)
Br2^ix—Sb1—Sb1ⁱⁱⁱ	89.80 (4)	Sb1^x—Br1—Sb1ⁱⁱ	145.757 (8)

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

Triformamidinium nonaiodidodiantimony (II) top

Crystal data top

(CH₆N₂)₃[Sb₂I₉]	D_x = 3.255 Mg m⁻³
M_r = 1421.63	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P6₃/mmc	Cell parameters from 5687 reflections
a = 8.7552 (4) Å	θ = 3.3–23.1°
c = 21.8474 (12) Å	µ = 11.42 mm⁻¹
V = 1450.32 (15) Å³	T = 295 K
Z = 2	Prism, clear reddish red
F(000) = 1194	0.13 × 0.13 × 0.09 mm

Data collection top

Agilent SuperNova Dual Source diffractometer with a HyPix-Arc 100 detector	896 independent reflections
Radiation source: micro-focus sealed X-ray tube, SuperNova (Mo) X-ray Source	456 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.104
Detector resolution: 10.0000 pixels mm^-1	θ_max = 31.2°, θ_min = 3.3°
ω scans	h = −12→12
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2022)	k = −12→12
T_min = 0.263, T_max = 1.000	l = −30→31
36967 measured reflections

Refinement top

Refinement on F²	1 restraint
Least-squares matrix: full	Primary atom site location: dual
R[F² > 2σ(F²)] = 0.056	H-atom parameters not defined
wR(F²) = 0.242	w = 1/[σ²(F_o²) + (0.1393P)²] where P = (F_o² + 2F_c²)/3
S = 1.05	(Δ/σ)_max = 0.001
896 reflections	Δρ_max = 1.24 e Å⁻³
19 parameters	Δρ_min = −0.44 e Å⁻³

Special details top

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

	x	y	z	U_iso*/U_eq
Sb1	0.666667	0.333333	0.34472 (6)	0.0811 (7)
I1	0.50293 (8)	0.49707 (8)	0.250000	0.1046 (7)
I2	0.82616 (9)	0.65233 (18)	0.41593 (6)	0.1311 (7)
C1	0.333333	0.666667	0.407 (3)	0.20 (3)
C2	1.000000	1.000000	0.250000	0.20 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Sb1	0.0797 (8)	0.0797 (8)	0.0837 (10)	0.0399 (4)	0.000	0.000
I1	0.1107 (11)	0.1107 (11)	0.1240 (12)	0.0792 (10)	0.000	0.000
I2	0.1462 (11)	0.1093 (10)	0.1256 (11)	0.0547 (5)	−0.0190 (3)	−0.0380 (6)
C1	0.116 (18)	0.116 (18)	0.38 (7)	0.058 (9)	0.000	0.000
C2	0.20 (5)	0.20 (5)	0.19 (7)	0.10 (2)	0.000	0.000

Geometric parameters (Å, º) top

Sb1—I1ⁱ	3.2323 (12)	Sb1—I2ⁱⁱⁱ	2.8758 (13)
Sb1—I1ⁱⁱ	3.2323 (12)	Sb1—I2	2.8759 (13)
Sb1—I1	3.2323 (12)	Sb1—I2^iv	2.8758 (13)
Sb1—I1ⁱⁱⁱ	3.2323 (12)	I1—I1ⁱⁱ	0.0000 (13)

I1ⁱⁱⁱ—Sb1—I1ⁱ	83.41 (3)	I2—Sb1—I1ⁱⁱ	91.34 (3)
I1ⁱ—Sb1—I1	83.41 (3)	I2ⁱⁱⁱ—Sb1—I1ⁱ	91.34 (3)
I1ⁱⁱⁱ—Sb1—I1	83.41 (3)	I2^iv—Sb1—I1ⁱ	91.34 (3)
I1ⁱⁱⁱ—Sb1—I1ⁱⁱ	83.41 (3)	I2ⁱⁱⁱ—Sb1—I1	172.94 (5)
I1—Sb1—I1ⁱⁱ	0.000 (18)	I2—Sb1—I1	91.34 (3)
I1ⁱ—Sb1—I1ⁱⁱ	83.41 (3)	I2^iv—Sb1—I1	91.34 (3)
I2ⁱⁱⁱ—Sb1—I1ⁱⁱⁱ	91.34 (3)	I2ⁱⁱⁱ—Sb1—I2	93.50 (5)
I2—Sb1—I1ⁱ	172.94 (5)	I2ⁱⁱⁱ—Sb1—I2^iv	93.50 (5)
I2^iv—Sb1—I1ⁱⁱ	91.34 (3)	I2^iv—Sb1—I2	93.50 (5)
I2^iv—Sb1—I1ⁱⁱⁱ	172.94 (5)	Sb1^v—I1—Sb1	79.62 (5)
I2ⁱⁱⁱ—Sb1—I1ⁱⁱ	172.94 (5)	I1ⁱⁱ—I1—Sb1^v	0 (10)
I2—Sb1—I1ⁱⁱⁱ	91.34 (3)	I1ⁱⁱ—I1—Sb1	0 (10)

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

Atomic position parameters, interatomic distances and bond angles obtained from the structural solution of SCXRD data collected at 295 K of FA₃Sb₂Br₉ top

See Table 2 for definitions.

Atom	x	y	z	Occ	W	U
Sb	1/3	2/3	0.31852 (12)	1	2d	0.1112 (8)
Br1	1/2	3/2	1/2	1	3f	0.1457 (11)
Br2	0.6278 (3)	0.81392 (16)	0.17401 (18)	1	6i	0.1709 (12)
C1	2/3	4/3	0.191 (4)	1	2d	0.21 (3)
C2	-3.00000	-1.00000	1/2	1	1b	0.22 (3)

Atoms	Interatomic distance	Atoms	Bond angle
Sb—Br1	3.0598 (7)	Br1—Sb—Br2	177.20 (6)
Sb—Br2	2.612 (2)	Br1—Sb—Br1	88.18 (3)
Br1—Br2	4.016 (3)	Br2—Sb—Br2	92.14 (8)

Atomic position parameters, interatomic distances (Å) and bond angles (°) obtained from the structural solution of SCXRD data collected at 295 K of FA₃Sb₂I₉ top

x, y and z are the position parameters of different atoms, and `Occ' is the occupancy of the atom at the determined position. W is the Wyckoff position notation and U is the anisotropic displacement parameter. C atoms are in place of the FA ion as explained in the text. Bond distances and angles were determined using the VESTA software suite (Version 3; Momma & Izumi, 2011). ["Br1—Sb1—Br1 88.18 (3)" 122.428 (18) in CIF]

Atom	x	y	z	Occ	W	U
Sb	2/3	1/3	0.34482 (6)	1	4f	0.0810 (6)
I1	0.50288 (8)	0.49712 (8)	1/2	1	6h	0.1312 (7)
I2	0.82610 (9)	0.65220 (18)	0.41593 (6)	1	12k	0.1312 (7)
C1	1/3	2/3	0.405 (4)	1	4f	0.21 (2)
C2	1.00000	1.00000	1/4	1	2b	0.20 (3)

Atoms	Interatomic distance	Atoms	Bond angle
Sb—I1	3.2323 (12)	I1—Sb—I2	172.94 (5)
Sb—I2	2.8758 (13)	I1—Sb—I1	83.41 (3)
I1—I2	4.3762 (15)	I2—Sb—I2	93.50 (5)

Acknowledgements

XPS was carried out at Harwell XPS, the National XPS Facility (EP/Y023587/1).

Data availability

Data for this article, including all processed data of the figures, are available at Zenodo in Origin format at https://doi.org/10.5281/zenodo.17578603.

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