Spontaneous enanti­omorphism in poly-phased alkaline salts of tris­(oxalato)ferrate(III): crystal structure of cubic NaRb5[Fe(C2O4)3]2

Piro, O.E.; Echeverría, G.A.; Baran, E.J.

doi:10.1107/S2056989018008022

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ISSN: 2056-9890

Volume 74| Part 7| July 2018| Pages 905-909

https://doi.org/10.1107/S2056989018008022

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Spontaneous enantiomorphism in poly-phased alkaline salts of tris(oxalato)ferrate(III): crystal structure of cubic NaRb₅[Fe(C₂O₄)₃]₂

O. E. Piro,^a G. A. Echeverría ^a ^* and E. J. Baran ^b

^aDepartamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata and IFLP(CONICET), C.C. 67, 1900 La Plata, Argentina, and ^bCentro de Química Inorgánica (CEQUINOR), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 962, 1900 La Plata, Argentina
^*Correspondence e-mail: geche@fisica.unlp.edu.ar

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 2 February 2018; accepted 30 May 2018; online 8 June 2018)

We show here that the phenomenon of spontaneous resolution of enantiomers occurs during the crystallization of the sodium and rubidium double salts of the transition metal complex tris(oxalato)ferrate(III), namely sodium pentarubidium bis[tris(oxalato)ferrate(III)], NaRb₅[Fe(C₂O₄)₃]₂. One enantiomer of the salt crystallizes in the cubic space group P4₃32 with Z = 4 and a Flack absolute structure parameter x = −0.01 (1) and its chiral counterpart in the space group P4₁32 with x = −0.00 (1). All metal ions are at crystallographic special positions: the iron(III) ion is on a threefold axis, coordinated by three oxalate dianions in a propeller-like conformation. One of the two independent rubidium ions is on a twofold axis in an eightfold coordination with neighbouring oxalate oxygen atoms, and the other one on a threefold axis in a sixfold RbO₆ coordination. The sodium ion is at a site of D₃ point group symmetry in a trigonal–antiprismatic NaO₆ coordination.

Keywords: absolute crystal structures; spontaneous resolution of enantiomorphs; sodium and rubidium salt of tris(oxalato)ferrate(III).

CCDC references: 1563459; 1563458

1. Chemical context

Chirality is the structural property by which a molecule or ion cannot be superposed upon its mirror image through translation and proper rotation operations. This concept along with the related ones of chiral crystal structures and space groups is discussed by Flack (2003 ). Chirality is at the core (among other research areas) of the not yet understood origin of the biomolecular asymmetry of life (Meierhenrich, 2008 ), enantioselective chemical reactions (Knowles, 2001 ; Noyori, 2001 ; Sharpless, 2001 ), biological activity of pharmaceuticals (Nguyen et al., 2006 ) and in the design of multifunctional solid-state materials endowed with optical activity and long-range magnetic order (Coronado et al., 2003 ) and also in the understanding of the physical properties of chiral liquid crystals and their tailoring for applications in opto-electronic devices (Goodby, 1998 ; Coles, 1998 ).

While attempting to crystallize the rubidium salt of the tris(oxalato)ferrate(III) transition metal complex, one of the preparations segregated into a poly-phased crystal system. It contained the intended Rb₃[Fe(C₂O₄)₃]·3H₂O compound (monoclinic P2₁/c), which turned out to be isotypic to the reported potassium salt (Junk, 2005 ; Piro et al., 2016 ), and the triclinic (P $[\overline{1}]$ ) Rb(C₂O₄H)(C₂O₄H₂)·2H₂O salt (Kherfi et al., 2010 ), which is isotypic to the ammonium analogue (Jarzembska et al., 2014 ). A third phase consisted of large green crystals of a new cubic (P4₃32) NaRb₅[Fe(C₂O₄)₃]₂ salt. Interestingly, the isotypic counterpart of this salt where rubidium is replaced by potassium has been reported by Wartchow (1997 ) to appear in a mixture with crystals of the monoclinic K₃[Fe(C₂O₄)₃]·3H₂O salt, hence confirming the tendency of potassium and rubidium alkaline ions to form isotypic crystal analogues (Piro et al., 2016). Curiously, in a previous work, Henneicke & Wartchow (1997 ) reported the chiral counterpart of the cubic NaK₅[Fe(C₂O₄)₃]₂ salt, which crystallizes in the space group P4₁32. This prompted us to search for the chiral rubidium analogue in the very same batch as the single-crystals that solved in the space group P4₃32 NaRb₅[Fe(C₂O₄)₃]₂. By chance, we picked a single crystal and submitted it to X-ray diffraction scrutiny to find that it now belonged to the chiral space group P4₁32. This strongly suggests that the NaM₅[Fe(C₂O₄)₃]₂ (M = K, Rb) crystal samples could be racemic conglomerates generated by spontaneous resolution, a rare event discovered by Louis Pasteur in 1848 (Pasteur, 1848a ,b ) in a famous experiment in which he hand-sorted the chirally resolved crystals of sodium ammonium tartrate tetrahydrate on the basis of their observed morphology and then examined their respective solutions with a polarimeter to find opposite rotations of the plane of light polarization (Flack, 2009 ). Recently, we found that the phenomenon could also have occurred in isotypic [M(Lap)₂]_n (M = Cd, Mn; HLap = 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphtoquinone, C₁₅H₁₄O₃) complexes whose enantiomers crystallize in the tetragonal and enantiomorphic space groups P4₃2₁2 and P4₁2₁2 (Farfán et al., 2015 ).

2. Structural commentary

Fig. 1 shows an ORTEP (Farrugia, 2012 ) drawing of the P4₃32 enantiomer of the title compound. Bond lengths and angles around iron(III) and within the oxalate dianion are listed in Table 1 and contact distances around the alkali ions are shown in Table 2. All metal ions are at crystallographic special positions while the oxalate anion is on a general position. The iron(III) ion is on a threefold axis, C₃ point group symmetry (Wyckoft c site), in an octahedral environment (FeO₆ core). It is coordinated to three, symmetry-related, oxalate anions acting as bidentate ligands through the oxygen atoms of their opposite carboxylic groups in a propeller-like conformation and along one electron pair lobe on each oxygen ligand. The FeO₆ bond geometry and metrics are consistent with the oxalate being a weak-field ligand that gives rise to the high-spin (S = 5/2) electronic ground state exhibited by the complex, as probed by magnetic susceptibility (Delgado et al., 2002 ) and ESR spectroscopy (Collison & Powell, 1990 ) in synthetic minguzzite, K₃[Fe(C₂O₄)₃]·3H₂O, by polarized electronic absorption spectroscopy in single crystal NaMg[(Fe, Al)(C₂O₄)₃]·9H₂O mixtures (Piper & Carlin, 1961 ) and also by Mössbauer spectroscopy in K₃[Fe(C₂O₄)₃]·3H₂O (Bancroft et al., 1970 ; Sato & Tominaga, 1979 ; Ladriere, 1992 ) and in the alkali (Na, Rb, Cs) family of tris(oxalato)ferrate(III) salts (Piro et al., 2016).

Table 1
Bond lengths and angles (Å, °) around iron(III) and within the oxalate dianion in NaRb₅[Fe(C₂O₄)₃]₂ P4₃32 enantiomer

(a) At a crystal site of C₃ point group symmetry.

Iron(III)^a		(C₂O₄)²⁻
Fe—O11	2.021 (4)	C1–O12	1.211 (7)	O12—C—O11	125.2 (6)
Fe—O21	1.989 (4)	C1–O11	1.286 (7)	O12—C1—C2	121.2 (6)
		C1—C2	1.540 (9)	O11—C1—C2	113.5 (5)
O21—Fe—O11	80.0 (2)	C2—O22	1.211 (7)	O22—C2—O21	125.3 (6)
O21—Fe—O21ⁱ	88.4 (2)	C2—O21	1.283 (7)	O22—C2—C1	121.1 (6)
O11—Fe—O11ⁱ	88.7 (2)			O21—C2—C1	113.6 (5)
O11—Fe—O21ⁱ	106.2 (2)
O11—Fe—O21ⁱⁱ	160.9 (2)
Symmetry codes: (i) −z + $[{1\over 2}]$ , −x + 1, y − $[{1\over 2}]$ ; (ii) −y + 1, z + $[{1\over 2}]$ , −x + $[{1\over 2}]$ .

Table 2
Bond lengths (Å) around the alkali metal ions in NaRb₅[Fe(C₂O₄)₃]₂ P4₃32 enantiomer.

(a) At a site of C₂ point group symmetry; (b) at a C₃ site; (c) at a D₃ site.

Rb1^a		Rb2^b		Na^c
Rb1—O11	3.009 (4)	Rb2—O22	2.808 (4)	Na—O12	2.439 (4)
Rb1—O11ⁱ	3.067 (4)	Rb2—O21ⁱⁱⁱ	3.114 (4)
Rb1—O22ⁱⁱ	2.788 (5)
Rb1—O12ⁱⁱ	3.133 (5)
Symmetry codes: (i) −y + 1, z + $[{1\over 2}]$ , −x + $[{1\over 2}]$ ; (ii) y − $[{1\over 2}]$ , −z + $[{3\over 2}]$ , −x + 1; (iii) −y + $[{5\over 4}]$ , −x + $[{5\over 4}]$ , −z + $[{1\over 4}]$ .

Figure 1
View of NaRb₅[Fe(C₂O₄)₃]₂ showing the atom labels and displacement ellipsoids at the 50% probability level. For clarity, only the minimum number of oxygen ligands around each metal ion has been labelled. The rest of the environmental oxygen atoms are generated through the symmetry operations of the corresponding point groups: C₃ (Fe), C₂ (Rb1), C₃ (Rb2) and D₃ (Na). Iron–oxalate bonds are indicated by double lines and alkali metal–oxygen contacts by single lines. Symmetry codes: (i) −y + 1, z + $[{1\over 2}]$ , −x + $[{1\over 2}]$ ; (ii) y − $[{1\over 2}]$ , −z + $[{3\over 2}]$ , −x + 1; (iii) −y + $[{5\over 4}]$ , −x + $[{5\over 4}]$ , −z + $[{1\over 4}]$ .

The planes of the carboxylic –COO⁻ groups of the oxalate ligand are slightly tilted from each other, by 12 (1)° around the C—C σ-bond. As expected, the C—O bond lengths involving the coordinated-to-metal oxygen atoms are significantly longer [1.286 (7) and 1.283 (7) Å] than the ones corresponding to the uncoordinated oxalate oxygen atoms [both equal to 1.211 (7) Å].

There are two independent rubidium ions, one (Rb1) lying on a twofold axis, C₂ point group symmetry (d site) in an eightfold coordination with neighbouring oxalate oxygen atoms, the other one (Rb2) on a threefold axis, C₃ point group (c site) in a sixfold coordination. The sodium ion is at a site of D₃ point group symmetry (a site) in a trigonal–antiprismatic NaO₆ coordination with one oxygen atom of six neighbouring, symmetry-related, oxalate ions.

When dealing with octahedral Fe(C₂O₄)₃ tris-chelated metal complexes, it is customary to describe its chirality employing Λ- and Δ-descriptors (Meierhenrich, 2008). It turns out that the enantiomeric complexes correlate with the corresponding chiral space groups, as indicated in Fig. 2.

Figure 2
Views of the Λ and Δ enantiomers of [Fe(C₂O₄)₃]³⁻.

The possibility of controlling the crystal chirality and therefore obtaining enhanced optical activity of functional materials has been discussed (Gruselle et al., 2006 ). To this purpose, two general synthetic routes have been developed to reach optically active coordination compounds, namely either by enantioselective synthesis using enantiopure chiral species, which yields enantiopure samples (Knof & von Zelewsky, 1999 ) or by spontaneous resolution upon crystallization from a racemate, which yields a conglomerate (Pérez-García & Amabilino, 2002 ). As explained above, the chiral NaRb₅[Fe(C₂O₄)₃]₂ crystals were obtained through the phenomena of spontaneous resolution from a racemic solution of [Fe(C₂O₄)₃]³⁻ complex ions into a racemic conglomerate. This is presumably followed by a structural inductive effect by these chiral molecular ions on the alkali metal ions through shared oxalate ligands. In fact, not only is the Fe^III ion a `stereogenic centre' in the Fe(C₂O₄)₃ tris-chelated metal complex, but so also are the sodium and one (Rb2) of the rubidium ions. These metal ions are in a distorted octahedral environment coordinated to six oxalate anions, acting as monodentate ligand through one of their oxygen atoms and resembling a six-bladed propeller-like conformation. From the structural data, it turns out that the chirality of this local arrangement around the alkaline ions is coincident with the one of the [Fe(C₂O₄)₃]³⁻ inductor and therefore the chiral crystals reported here can be more conveniently described as Λ-NaΛ-Rb₂Rb₃[Λ-Fe(C₂O₄)₃]₂ (P4₃32) and Δ-NaΔ-Rb₂Rb₃[Δ-Fe(C₂O₄)₃]₂ (P4₁32). However, no definitive chirality can be unambiguously assigned to the other independent rubidium (Rb1) ion which is in an eightfold polyhedral coordination.

3. Database survey

The formation of racemic conglomerates of single crystals, adequate for structural X-ray diffraction, generated by spontaneous resolution is an infrequent phenomenon. In fact, a search of the Cambridge Structural Database (Groom et al., 2016 ) invoking the term `spontaneous resolution' showed seventeen entries, and another one using as a target `chiral crystals' produced a further four hits. Among them there were reported the chiral to each other (M)- and (P)-catena-{[μ₂-2-(imidazo[4,5-f](1,10)phenanthrolin-2-yl)benzoato-N,N′,O]aquachlorozinc(II)} (CSD refcodes EJINOB and EJINUH; Wei et al., 2011 ) and catena-[(μ₈-benzene-1,3,5-tricarboxylato)lithiumzinc] (CSD refcodes WAJHUM and WAJJAU; Xie et al., 2010 ).

4. Synthesis and crystallization

As stated in the Chemical context, in one of the preparations generated during the synthesis of the rubidium salt of [Fe(C₂O₄)₃]³⁻, by reaction of freshly precipitated Fe(OH)₃ (obtained by dropwise addition of a small excess of 20% NaOH to an Fe^III solution) with rubidium oxalate: Fe(OH)₃ + 3Rb(HC₂O₄) + 3H₂O → Rb₃[Fe(C₂O₄)₃]·3H₂O + 3H₂O) (Piro et al., 2016), we found a relatively complex reaction giving rise to a poly-phased crystal mixture, from which the NaRb₅[Fe(C₂O₄)₃]₂ chiral pair could be isolated.

5. Refinement details

Crystal data, data collection procedure and structure refinement results are summarized in Table 3. The structure was solved by intrinsic phasing with SHELXT (Sheldrick, 2015a ). The stereoisomers were determined through refinement of the Flack absolute structure parameter. This is the fractional contribution to the diffraction pattern due to the molecule racemic twin and for the correct enantiomeric crystal it should be zero to within experimental error.

Table 3
Experimental details

	Cubic, P4₃32	Cubic, P4₁32
Crystal data
Chemical formula	NaRb₅[Fe(C₂O₄)₃]₂	NaRb₅[Fe(C₂O₄)₃]₂
M_r	1090.16	1090.16
Temperature (K)	297	293
a (Å)	13.8058 (4)	13.7995 (3)
V (Å³)	2631.4 (2)	2627.79 (17)
Z	4	4
Radiation type	Mo Kα	Mo Kα
μ (mm⁻¹)	10.42	10.43
Crystal size (mm)	0.48 × 0.42 × 0.38	0.48 × 0.35 × 0.25

Data collection
Diffractometer	Agilent Xcalibur Eos Gemini	Rigaku Oxford Diffraction Xcalibur, Eos, Gemini
Absorption correction	Multi-scan (CrysAlis PRO; Agilent, 2014 )	Multi-scan (CrysAlis PRO; Rigaku OD, 2015 $[Rigaku OD (2014). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ )
T_min, T_max	0.690, 1.000	0.786, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	2960, 959, 767	4284, 961, 814
R_int	0.043	0.038
(sin θ/λ)_max (Å⁻¹)	0.638	0.638

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.035, 0.064, 1.00	0.032, 0.068, 1.02
No. of reflections	959	961
No. of parameters	68	68
Δρ_max, Δρ_min (e Å⁻³)	0.84, −0.85	1.02, −0.95
Absolute structure	Flack x determined using 225 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )	Flack x determined using 251 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013).
Absolute structure parameter	−0.013 (12)	−0.003 (10)
Computer programs: CrysAlis PRO (Agilent, 2014; Rigaku OD, 2015 $[Rigaku OD (2014). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ ), SHELXT (Sheldrick, 2015a), SHELXL2014 (Sheldrick, 2015b ) and ORTEP-3 for Windows (Farrugia, 2012).

Supporting information

CCDC references: 1563459; 1563458

Crystal structure: contains datablocks P4332, P4132, global. DOI: https://doi.org/10.1107/S2056989018008022/hb7735sup1.cif

Structure factors: contains datablock P4332. DOI: https://doi.org/10.1107/S2056989018008022/hb7735P4332sup2.hkl

Structure factors: contains datablock P4132. DOI: https://doi.org/10.1107/S2056989018008022/hb7735P4132sup3.hkl

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Agilent, 2014) for P4332; CrysAlis PRO (Rigaku OD, 2015) for P4132. Cell refinement: CrysAlis PRO (Agilent, 2014) for P4332; CrysAlis PRO (Rigaku OD, 2015) for P4132. Data reduction: CrysAlis PRO (Agilent, 2014) for P4332; CrysAlis PRO (Rigaku OD, 2015) for P4132. For both structures, program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015b).

Sodium pentarubidium bis[tris(oxalato)ferrate(III)] (P4332) top

Crystal data top

NaRb₅[Fe(C₂O₄)₃]₂	Mo Kα radiation, λ = 0.71073 Å
M_r = 1090.16	Cell parameters from 922 reflections
Cubic, P4₃32	θ = 3.6–27.3°
a = 13.8058 (4) Å	µ = 10.42 mm⁻¹
V = 2631.4 (2) Å³	T = 297 K
Z = 4	Fragment, green
F(000) = 2048	0.48 × 0.42 × 0.38 mm
D_x = 2.752 Mg m⁻³

Data collection top

Agilent Xcalibur Eos Gemini diffractometer	959 independent reflections
Radiation source: Enhance (Mo) X-ray Source	767 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.043
Detector resolution: 16.0604 pixels mm^-1	θ_max = 27.0°, θ_min = 3.3°
ω scans	h = −8→17
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014)	k = −11→16
T_min = 0.690, T_max = 1.000	l = −8→10
2960 measured reflections

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0274P)²] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.035	(Δ/σ)_max < 0.001
wR(F²) = 0.064	Δρ_max = 0.84 e Å⁻³
S = 1.00	Δρ_min = −0.85 e Å⁻³
959 reflections	Absolute structure: Flack x determined using 225 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
68 parameters	Absolute structure parameter: −0.013 (12)
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
C1	0.3861 (5)	0.8068 (4)	0.3863 (5)	0.0207 (13)
C2	0.4510 (5)	0.7715 (5)	0.3027 (5)	0.0234 (16)
O11	0.2953 (3)	0.7918 (3)	0.3718 (3)	0.0241 (10)
O12	0.4203 (3)	0.8466 (3)	0.4566 (3)	0.0312 (11)
O21	0.4037 (3)	0.7481 (3)	0.2262 (3)	0.0287 (10)
O22	0.5380 (3)	0.7665 (4)	0.3119 (3)	0.0402 (13)
Fe	0.26048 (6)	0.73952 (6)	0.23952 (6)	0.0209 (4)
Rb1	0.25612 (5)	1.00612 (5)	0.3750	0.0290 (3)
Rb2	0.67150 (6)	0.82850 (6)	0.17150 (6)	0.0444 (4)
Na	0.3750	0.8750	0.6250	0.0218 (13)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.025 (3)	0.020 (3)	0.017 (3)	−0.001 (3)	−0.001 (3)	0.006 (3)
C2	0.021 (3)	0.029 (4)	0.020 (3)	0.002 (3)	0.000 (3)	0.004 (3)
O11	0.020 (2)	0.032 (3)	0.020 (2)	0.000 (2)	0.002 (2)	0.000 (2)
O12	0.034 (3)	0.041 (3)	0.019 (2)	−0.003 (2)	−0.004 (2)	−0.002 (2)
O21	0.023 (2)	0.044 (3)	0.019 (2)	−0.004 (2)	0.006 (2)	−0.006 (2)
O22	0.020 (2)	0.069 (4)	0.032 (3)	0.004 (3)	0.003 (2)	0.002 (3)
Fe	0.0209 (4)	0.0209 (4)	0.0209 (4)	−0.0006 (4)	−0.0006 (4)	0.0006 (4)
Rb1	0.0290 (3)	0.0290 (3)	0.0288 (5)	−0.0018 (5)	0.0051 (3)	−0.0051 (3)
Rb2	0.0444 (4)	0.0444 (4)	0.0444 (4)	−0.0115 (4)	0.0115 (4)	−0.0115 (4)
Na	0.0218 (13)	0.0218 (13)	0.0218 (13)	0.0014 (16)	−0.0014 (16)	−0.0014 (16)

Geometric parameters (Å, º) top

C1—O12	1.211 (7)	Rb1—O22^v	2.788 (5)
C1—O11	1.286 (7)	Rb1—O22^vi	2.788 (5)
C1—C2	1.540 (9)	Rb1—O11^vii	3.009 (4)
C2—O22	1.211 (7)	Rb1—O11^iv	3.067 (4)
C2—O21	1.283 (7)	Rb1—O11^viii	3.067 (4)
O11—Fe	2.021 (4)	Rb1—O12^v	3.133 (5)
O11—Rb1	3.009 (4)	Rb1—O12^vi	3.133 (5)
O11—Rb1ⁱ	3.067 (4)	Rb1—O12^vii	3.354 (5)
O12—Na	2.439 (4)	Rb2—O22^ix	2.808 (4)
O12—Rb1ⁱⁱ	3.133 (5)	Rb2—O22^x	2.808 (4)
O12—Rb1	3.354 (5)	Rb2—O21ⁱⁱⁱ	3.114 (4)
O21—Fe	1.989 (4)	Rb2—O21^xi	3.114 (4)
O21—Rb2ⁱⁱⁱ	3.114 (4)	Rb2—O21^vi	3.114 (4)
O22—Rb1ⁱⁱ	2.788 (5)	Na—O12^xii	2.439 (4)
O22—Rb2	2.808 (4)	Na—O12ⁱⁱ	2.439 (4)
Fe—O21^iv	1.989 (4)	Na—O12^xiii	2.439 (4)
Fe—O21ⁱ	1.989 (4)	Na—O12^viii	2.439 (4)
Fe—O11ⁱ	2.021 (4)	Na—O12^v	2.439 (4)
Fe—O11^iv	2.021 (4)

O12—C1—O11	125.2 (6)	O11^vii—Rb1—O12^v	110.45 (11)
O12—C1—C2	121.2 (6)	O11^iv—Rb1—O12^v	151.29 (11)
O11—C1—C2	113.5 (5)	O11^viii—Rb1—O12^v	65.47 (11)
O22—C2—O21	125.3 (6)	O22^v—Rb1—O12^vi	91.18 (12)
O22—C2—C1	121.1 (6)	O22^vi—Rb1—O12^vi	56.14 (12)
O21—C2—C1	113.6 (5)	O11—Rb1—O12^vi	110.45 (11)
C1—O11—Fe	115.5 (4)	O11^vii—Rb1—O12^vi	95.92 (11)
C1—O11—Rb1	90.8 (3)	O11^iv—Rb1—O12^vi	65.47 (11)
Fe—O11—Rb1	108.75 (16)	O11^viii—Rb1—O12^vi	151.29 (11)
C1—O11—Rb1ⁱ	133.5 (4)	O12^v—Rb1—O12^vi	133.07 (16)
Fe—O11—Rb1ⁱ	106.67 (16)	O22^v—Rb1—O12^vii	64.52 (12)
Rb1—O11—Rb1ⁱ	93.73 (11)	O22^vi—Rb1—O12^vii	114.33 (13)
C1—O12—Na	137.5 (4)	O11—Rb1—O12^vii	141.04 (11)
C1—O12—Rb1ⁱⁱ	107.6 (4)	O11^vii—Rb1—O12^vii	40.34 (11)
Na—O12—Rb1ⁱⁱ	97.96 (14)	O11^iv—Rb1—O12^vii	90.55 (10)
C1—O12—Rb1	76.5 (4)	O11^viii—Rb1—O12^vii	90.35 (11)
Na—O12—Rb1	92.39 (13)	O12^v—Rb1—O12^vii	116.99 (13)
Rb1ⁱⁱ—O12—Rb1	157.89 (15)	O12^vi—Rb1—O12^vii	62.32 (15)
C2—O21—Fe	116.4 (4)	O22^v—Rb1—O12	114.33 (14)
C2—O21—Rb2ⁱⁱⁱ	133.5 (4)	O22^vi—Rb1—O12	64.52 (12)
Fe—O21—Rb2ⁱⁱⁱ	95.43 (15)	O11—Rb1—O12	40.34 (11)
C2—O22—Rb1ⁱⁱ	121.7 (4)	O11^vii—Rb1—O12	141.04 (11)
C2—O22—Rb2	124.2 (4)	O11^iv—Rb1—O12	90.35 (11)
Rb1ⁱⁱ—O22—Rb2	110.80 (17)	O11^viii—Rb1—O12	90.55 (10)
O21^iv—Fe—O21ⁱ	88.42 (18)	O12^v—Rb1—O12	62.32 (15)
O21^iv—Fe—O21	88.43 (18)	O12^vi—Rb1—O12	116.99 (13)
O21ⁱ—Fe—O21	88.42 (18)	O12^vii—Rb1—O12	178.45 (16)
O21^iv—Fe—O11	160.91 (17)	O22^ix—Rb2—O22^x	116.27 (7)
O21ⁱ—Fe—O11	106.20 (17)	O22^ix—Rb2—O22	116.27 (7)
O21—Fe—O11	79.96 (16)	O22^x—Rb2—O22	116.27 (7)
O21^iv—Fe—O11ⁱ	106.20 (17)	O22^ix—Rb2—O21ⁱⁱⁱ	131.79 (14)
O21ⁱ—Fe—O11ⁱ	79.96 (16)	O22^x—Rb2—O21ⁱⁱⁱ	81.60 (13)
O21—Fe—O11ⁱ	160.91 (17)	O22—Rb2—O21ⁱⁱⁱ	89.01 (12)
O11—Fe—O11ⁱ	88.73 (17)	O22^ix—Rb2—O21^xi	81.60 (13)
O21^iv—Fe—O11^iv	79.96 (16)	O22^x—Rb2—O21^xi	89.01 (12)
O21ⁱ—Fe—O11^iv	160.91 (17)	O22—Rb2—O21^xi	131.79 (14)
O21—Fe—O11^iv	106.20 (17)	O21ⁱⁱⁱ—Rb2—O21^xi	52.88 (13)
O11—Fe—O11^iv	88.72 (17)	O22^ix—Rb2—O21^vi	89.01 (12)
O11ⁱ—Fe—O11^iv	88.73 (17)	O22^x—Rb2—O21^vi	131.79 (14)
O22^v—Rb1—O22^vi	95.3 (2)	O22—Rb2—O21^vi	81.60 (13)
O22^v—Rb1—O11	152.05 (12)	O21ⁱⁱⁱ—Rb2—O21^vi	52.88 (13)
O22^vi—Rb1—O11	83.24 (13)	O21^xi—Rb2—O21^vi	52.88 (13)
O22^v—Rb1—O11^vii	83.24 (13)	O12—Na—O12^xii	76.1 (2)
O22^vi—Rb1—O11^vii	152.05 (12)	O12—Na—O12ⁱⁱ	87.13 (15)
O11—Rb1—O11^vii	110.74 (16)	O12^xii—Na—O12ⁱⁱ	120.9 (2)
O22^v—Rb1—O11^iv	152.40 (12)	O12—Na—O12^xiii	145.7 (2)
O22^vi—Rb1—O11^iv	83.98 (12)	O12^xii—Na—O12^xiii	87.13 (15)
O11—Rb1—O11^iv	55.43 (15)	O12ⁱⁱ—Na—O12^xiii	76.1 (2)
O11^vii—Rb1—O11^iv	84.73 (11)	O12—Na—O12^viii	120.9 (2)
O22^v—Rb1—O11^viii	83.98 (12)	O12^xii—Na—O12^viii	87.13 (15)
O22^vi—Rb1—O11^viii	152.40 (12)	O12ⁱⁱ—Na—O12^viii	145.7 (2)
O11—Rb1—O11^viii	84.73 (11)	O12^xiii—Na—O12^viii	87.13 (15)
O11^vii—Rb1—O11^viii	55.43 (15)	O12—Na—O12^v	87.13 (15)
O11^iv—Rb1—O11^viii	109.10 (16)	O12^xii—Na—O12^v	145.7 (2)
O22^v—Rb1—O12^v	56.14 (12)	O12ⁱⁱ—Na—O12^v	87.13 (15)
O22^vi—Rb1—O12^v	91.18 (12)	O12^xiii—Na—O12^v	120.9 (2)
O11—Rb1—O12^v	95.93 (11)	O12^viii—Na—O12^v	76.1 (2)

O12—C1—C2—O22	13.4 (10)	Rb1ⁱⁱ—C1—O11—Rb1ⁱ	44.6 (12)
O11—C1—C2—O22	−168.2 (6)	O11—C1—O12—Na	24.7 (10)
Rb1—C1—C2—O22	115.8 (6)	C2—C1—O12—Na	−157.1 (4)
Rb1ⁱⁱ—C1—C2—O22	−14.0 (6)	Rb1—C1—O12—Na	78.5 (5)
O12—C1—C2—O21	−167.4 (6)	Rb1ⁱⁱ—C1—O12—Na	−124.1 (6)
O11—C1—C2—O21	11.0 (8)	O11—C1—O12—Rb1ⁱⁱ	148.8 (5)
Rb1—C1—C2—O21	−65.0 (7)	C2—C1—O12—Rb1ⁱⁱ	−32.9 (6)
Rb1ⁱⁱ—C1—C2—O21	165.3 (5)	Rb1—C1—O12—Rb1ⁱⁱ	−157.41 (18)
O12—C1—C2—Rb1ⁱⁱ	27.3 (5)	O11—C1—O12—Rb1	−53.8 (6)
O11—C1—C2—Rb1ⁱⁱ	−154.2 (5)	C2—C1—O12—Rb1	124.5 (6)
Rb1—C1—C2—Rb1ⁱⁱ	129.8 (3)	Rb1ⁱⁱ—C1—O12—Rb1	157.41 (18)
O12—C1—C2—Rb2	−33.2 (10)	O22—C2—O21—Fe	168.6 (6)
O11—C1—C2—Rb2	145.2 (5)	C1—C2—O21—Fe	−10.6 (7)
Rb1—C1—C2—Rb2	69.2 (7)	Rb1ⁱⁱ—C2—O21—Fe	124.4 (11)
Rb1ⁱⁱ—C1—C2—Rb2	−60.5 (5)	Rb2—C2—O21—Fe	−164.6 (2)
O12—C1—O11—Fe	172.3 (5)	O22—C2—O21—Rb2ⁱⁱⁱ	40.5 (10)
C2—C1—O11—Fe	−6.1 (6)	C1—C2—O21—Rb2ⁱⁱⁱ	−138.7 (4)
Rb1—C1—O11—Fe	111.3 (3)	Rb1ⁱⁱ—C2—O21—Rb2ⁱⁱⁱ	−3.7 (16)
Rb1ⁱⁱ—C1—O11—Fe	−108.2 (9)	Rb2—C2—O21—Rb2ⁱⁱⁱ	67.3 (5)
O12—C1—O11—Rb1	61.0 (6)	O21—C2—O22—Rb1ⁱⁱ	−158.0 (5)
C2—C1—O11—Rb1	−117.4 (4)	C1—C2—O22—Rb1ⁱⁱ	21.1 (9)
Rb1ⁱⁱ—C1—O11—Rb1	140.5 (9)	Rb2—C2—O22—Rb1ⁱⁱ	157.4 (7)
O12—C1—O11—Rb1ⁱ	−34.9 (9)	O21—C2—O22—Rb2	44.5 (9)
C2—C1—O11—Rb1ⁱ	146.7 (4)	C1—C2—O22—Rb2	−136.3 (5)
Rb1—C1—O11—Rb1ⁱ	−95.9 (4)

Symmetry codes: (i) −z+1/2, −x+1, y−1/2; (ii) −z+1, x+1/2, −y+3/2; (iii) −y+5/4, −x+5/4, −z+1/4; (iv) −y+1, z+1/2, −x+1/2; (v) y−1/2, −z+3/2, −x+1; (vi) −z+3/4, y+1/4, x−1/4; (vii) y−3/4, x+3/4, −z+3/4; (viii) z−1/4, −y+7/4, x+1/4; (ix) z+1/2, −x+3/2, −y+1; (x) −y+3/2, −z+1, x−1/2; (xi) x+1/4, z+3/4, −y+3/4; (xii) −x+3/4, z+1/4, y−1/4; (xiii) −y+5/4, −x+5/4, −z+5/4.

sodium and rubidium tris(oxalate)ferrate(III) (P4132) top

Crystal data top

NaRb₅[Fe(C₂O₄)₃]₂	Mo Kα radiation, λ = 0.71073 Å
M_r = 1090.16	Cell parameters from 1328 reflections
Cubic, P4₁32	θ = 4.4–27.3°
a = 13.7995 (3) Å	µ = 10.43 mm⁻¹
V = 2627.79 (17) Å³	T = 293 K
Z = 4	Fragment, green
F(000) = 2048	0.48 × 0.35 × 0.25 mm
D_x = 2.756 Mg m⁻³

Data collection top

Rigaku Oxford Diffraction Xcalibur, Eos, Gemini diffractometer	961 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	814 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.038
Detector resolution: 16.0604 pixels mm^-1	θ_max = 27.0°, θ_min = 3.3°
ω scans	h = −14→16
Absorption correction: multi-scan (CrysAlisPro; Rigaku OD, 2015)	k = −14→10
T_min = 0.786, T_max = 1.000	l = −17→16
4284 measured reflections

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.031P)² + 3.9422P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.032	(Δ/σ)_max < 0.001
wR(F²) = 0.068	Δρ_max = 1.02 e Å⁻³
S = 1.02	Δρ_min = −0.95 e Å⁻³
961 reflections	Absolute structure: Flack x determined using 251 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013).
68 parameters	Absolute structure parameter: −0.003 (10)
0 restraints

Special details top

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

	x	y	z	U_iso*/U_eq
C1	0.1366 (5)	0.5569 (4)	0.1362 (5)	0.0228 (14)
C2	0.0522 (5)	0.5213 (5)	0.2007 (5)	0.0256 (15)
O11	0.1218 (3)	0.5418 (3)	0.0448 (3)	0.0254 (10)
O12	−0.0240 (3)	0.4977 (3)	0.1533 (3)	0.0291 (10)
O21	0.2066 (3)	0.5967 (3)	0.1708 (3)	0.0327 (11)
O22	0.0621 (4)	0.5170 (4)	0.2882 (4)	0.0422 (14)
Fe	−0.01047 (6)	0.48953 (6)	0.01047 (6)	0.0218 (4)
Rb1	0.24391 (5)	0.50609 (5)	0.3750	0.0291 (2)
Rb2	−0.07858 (6)	0.57858 (6)	0.42142 (6)	0.0451 (4)
Na	0.3750	0.6250	0.1250	0.0234 (12)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.018 (3)	0.024 (3)	0.027 (4)	0.007 (3)	−0.001 (3)	0.001 (3)
C2	0.026 (4)	0.034 (4)	0.017 (3)	0.006 (3)	0.003 (3)	−0.001 (3)
O11	0.023 (2)	0.032 (3)	0.022 (3)	−0.003 (2)	0.002 (2)	−0.0003 (18)
O12	0.020 (2)	0.042 (3)	0.025 (3)	−0.005 (2)	0.0052 (18)	−0.005 (2)
O21	0.022 (3)	0.041 (3)	0.036 (3)	−0.003 (2)	−0.005 (2)	0.000 (2)
O22	0.032 (3)	0.069 (4)	0.025 (3)	−0.001 (3)	0.003 (2)	0.002 (3)
Fe	0.0218 (4)	0.0218 (4)	0.0218 (4)	0.0003 (4)	−0.0003 (4)	−0.0003 (4)
Rb1	0.0292 (3)	0.0292 (3)	0.0290 (5)	0.0020 (4)	−0.0047 (3)	−0.0047 (3)
Rb2	0.0451 (4)	0.0451 (4)	0.0451 (4)	−0.0124 (4)	0.0124 (4)	−0.0124 (4)
Na	0.0234 (12)	0.0234 (12)	0.0234 (12)	−0.0014 (15)	−0.0014 (15)	0.0014 (15)

Geometric parameters (Å, º) top

C1—O21	1.210 (7)	Rb1—O22^vi	2.785 (5)
C1—O11	1.295 (8)	Rb1—O11^vii	3.006 (4)
C1—C2	1.546 (9)	Rb1—O11^viii	3.006 (4)
C2—O22	1.216 (8)	Rb1—O11^ix	3.059 (4)
C2—O12	1.280 (7)	Rb1—O11^x	3.059 (4)
O11—Fe	2.019 (4)	Rb1—O21^vi	3.125 (5)
O11—Rb1ⁱ	3.006 (4)	Rb1—O21^viii	3.357 (5)
O11—Rb1ⁱⁱ	3.059 (4)	Rb1—O21^vii	3.357 (5)
O12—Fe	1.983 (4)	Rb2—O22^xi	2.805 (5)
O12—Rb2ⁱⁱⁱ	3.106 (4)	Rb2—O22^xii	2.805 (5)
O21—Na	2.439 (4)	Rb2—O12^xiii	3.106 (4)
O21—Rb1	3.125 (5)	Rb2—O12^xiv	3.106 (4)
O21—Rb1ⁱ	3.357 (5)	Rb2—O12^xv	3.106 (4)
O22—Rb1	2.785 (5)	Na—O21^vii	2.439 (4)
O22—Rb2	2.805 (5)	Na—O21^x	2.439 (4)
Fe—O12^iv	1.983 (4)	Na—O21^xvi	2.439 (4)
Fe—O12^v	1.983 (4)	Na—O21ⁱ	2.439 (4)
Fe—O11^v	2.019 (4)	Na—O21^xvii	2.439 (4)
Fe—O11^iv	2.019 (4)

O21—C1—O11	125.7 (6)	O11^viii—Rb1—O11^x	55.34 (16)
O21—C1—C2	121.2 (6)	O11^ix—Rb1—O11^x	108.96 (17)
O11—C1—C2	113.0 (5)	O22^vi—Rb1—O21^vi	56.08 (13)
O21—C1—Rb1ⁱ	82.8 (4)	O22—Rb1—O21^vi	91.06 (13)
O11—C1—Rb1ⁱ	66.1 (3)	O11^vii—Rb1—O21^vi	110.57 (12)
C2—C1—Rb1ⁱ	123.0 (4)	O11^viii—Rb1—O21^vi	95.97 (11)
O21—C1—Rb1	53.9 (3)	O11^ix—Rb1—O21^vi	65.63 (12)
O11—C1—Rb1	154.8 (4)	O11^x—Rb1—O21^vi	151.23 (11)
C2—C1—Rb1	74.1 (3)	O22^vi—Rb1—O21	91.06 (13)
Rb1ⁱ—C1—Rb1	131.92 (18)	O22—Rb1—O21	56.09 (13)
O22—C2—O12	125.9 (6)	O11^vii—Rb1—O21	95.97 (11)
O22—C2—C1	120.2 (6)	O11^viii—Rb1—O21	110.57 (12)
O12—C2—C1	113.9 (5)	O11^ix—Rb1—O21	151.23 (11)
O22—C2—Rb1	41.2 (3)	O11^x—Rb1—O21	65.63 (12)
O12—C2—Rb1	159.2 (4)	O21^vi—Rb1—O21	132.93 (17)
C1—C2—Rb1	81.3 (3)	O22^vi—Rb1—O21^viii	114.16 (14)
O22—C2—Rb2	39.9 (3)	O22—Rb1—O21^viii	64.53 (13)
O12—C2—Rb2	94.4 (4)	O11^vii—Rb1—O21^viii	141.04 (12)
C1—C2—Rb2	142.1 (4)	O11^viii—Rb1—O21^viii	40.54 (11)
Rb1—C2—Rb2	79.41 (13)	O11^ix—Rb1—O21^viii	90.67 (11)
C1—O11—Fe	115.3 (4)	O11^x—Rb1—O21^viii	90.36 (11)
C1—O11—Rb1ⁱ	90.7 (3)	O21^vi—Rb1—O21^viii	62.26 (16)
Fe—O11—Rb1ⁱ	108.83 (17)	O21—Rb1—O21^viii	116.94 (14)
C1—O11—Rb1ⁱⁱ	133.3 (4)	C1^vii—Rb1—O21^viii	160.09 (13)
Fe—O11—Rb1ⁱⁱ	106.92 (16)	C1^viii—Rb1—O21^viii	20.95 (13)
Rb1ⁱ—O11—Rb1ⁱⁱ	93.89 (12)	O22^vi—Rb1—O21^vii	64.53 (13)
C2—O12—Fe	116.4 (4)	O22—Rb1—O21^vii	114.16 (14)
C2—O12—Rb2ⁱⁱⁱ	133.5 (4)	O11^vii—Rb1—O21^vii	40.54 (11)
Fe—O12—Rb2ⁱⁱⁱ	95.68 (16)	O11^viii—Rb1—O21^vii	141.04 (12)
C1—O21—Na	137.0 (4)	O11^ix—Rb1—O21^vii	90.36 (11)
C1—O21—Rb1	107.8 (4)	O11^x—Rb1—O21^vii	90.67 (11)
Na—O21—Rb1	98.10 (14)	O21^vi—Rb1—O21^vii	116.94 (14)
C1—O21—Rb1ⁱ	76.2 (4)	O21—Rb1—O21^vii	62.26 (16)
Na—O21—Rb1ⁱ	92.25 (14)	C1^vii—Rb1—O21^vii	20.95 (13)
Rb1—O21—Rb1ⁱ	158.07 (17)	C1^viii—Rb1—O21^vii	160.09 (13)
C2—O22—Rb1	122.0 (4)	O21^viii—Rb1—O21^vii	178.23 (16)
C2—O22—Rb2	124.0 (5)	O22—Rb2—O22^xi	116.26 (7)
Rb1—O22—Rb2	110.97 (18)	O22—Rb2—O22^xii	116.26 (7)
O12—Fe—O12^iv	88.19 (18)	O22^xi—Rb2—O22^xii	116.26 (7)
O12—Fe—O12^v	88.19 (18)	O22—Rb2—O12^xiii	89.16 (13)
O12^iv—Fe—O12^v	88.19 (18)	O22^xi—Rb2—O12^xiii	131.71 (15)
O12—Fe—O11^v	161.01 (17)	O22^xii—Rb2—O12^xiii	81.59 (14)
O12^iv—Fe—O11^v	106.36 (18)	O22—Rb2—O12^xiv	131.71 (15)
O12^v—Fe—O11^v	80.31 (17)	O22^xi—Rb2—O12^xiv	81.59 (14)
O12—Fe—O11^iv	106.35 (18)	O22^xii—Rb2—O12^xiv	89.16 (13)
O12^iv—Fe—O11^iv	80.31 (17)	O12^xiii—Rb2—O12^xiv	52.74 (13)
O12^v—Fe—O11^iv	161.01 (17)	O22—Rb2—O12^xv	81.59 (14)
O11^v—Fe—O11^iv	88.44 (18)	O22^xi—Rb2—O12^xv	89.16 (13)
O12—Fe—O11	80.31 (17)	O22^xii—Rb2—O12^xv	131.71 (15)
O12^iv—Fe—O11	161.01 (17)	O12^xiii—Rb2—O12^xv	52.74 (13)
O12^v—Fe—O11	106.36 (18)	O12^xiv—Rb2—O12^xv	52.74 (13)
O11^v—Fe—O11	88.43 (18)	O21—Na—O21^vii	86.98 (16)
O11^iv—Fe—O11	88.43 (18)	O21—Na—O21^x	76.2 (2)
O22^vi—Rb1—O22	95.0 (2)	O21^vii—Na—O21^x	121.3 (2)
O22^vi—Rb1—O11^vii	83.52 (14)	O21—Na—O21^xvi	145.5 (2)
O22—Rb1—O11^vii	152.04 (13)	O21^vii—Na—O21^xvi	76.2 (2)
O22^vi—Rb1—O11^viii	152.04 (13)	O21^x—Na—O21^xvi	86.97 (16)
O22—Rb1—O11^viii	83.52 (14)	O21—Na—O21ⁱ	86.97 (16)
O11^vii—Rb1—O11^viii	110.46 (16)	O21^vii—Na—O21ⁱ	86.97 (16)
O22^vi—Rb1—O11^ix	84.14 (13)	O21^x—Na—O21ⁱ	145.5 (2)
O22—Rb1—O11^ix	152.50 (13)	O21^xvi—Na—O21ⁱ	121.3 (2)
O11^vii—Rb1—O11^ix	55.34 (16)	O21—Na—O21^xvii	121.3 (2)
O11^viii—Rb1—O11^ix	84.61 (12)	O21^vii—Na—O21^xvii	145.5 (2)
O22^vi—Rb1—O11^x	152.49 (13)	O21^x—Na—O21^xvii	86.97 (16)
O22—Rb1—O11^x	84.14 (13)	O21^xvi—Na—O21^xvii	86.97 (16)
O11^vii—Rb1—O11^x	84.61 (12)	O21ⁱ—Na—O21^xvii	76.2 (2)

O21—C1—C2—O22	−13.0 (10)	Rb1—C1—O11—Rb1ⁱⁱ	−44.8 (12)
O11—C1—C2—O22	168.7 (6)	O22—C2—O12—Fe	−169.1 (6)
Rb1ⁱ—C1—C2—O22	−115.7 (6)	C1—C2—O12—Fe	10.3 (7)
Rb1—C1—C2—O22	14.4 (6)	Rb1—C2—O12—Fe	−124.2 (11)
O21—C1—C2—O12	167.5 (6)	Rb2—C2—O12—Fe	164.4 (2)
O11—C1—C2—O12	−10.8 (8)	O22—C2—O12—Rb2ⁱⁱⁱ	−40.6 (10)
Rb1ⁱ—C1—C2—O12	64.8 (6)	C1—C2—O12—Rb2ⁱⁱⁱ	138.9 (4)
Rb1—C1—C2—O12	−165.1 (5)	Rb1—C2—O12—Rb2ⁱⁱⁱ	4.4 (16)
O21—C1—C2—Rb1	−27.4 (5)	Rb2—C2—O12—Rb2ⁱⁱⁱ	−67.1 (5)
O11—C1—C2—Rb1	154.3 (5)	O11—C1—O21—Na	−24.5 (10)
Rb1ⁱ—C1—C2—Rb1	−130.1 (3)	C2—C1—O21—Na	157.3 (4)
O21—C1—C2—Rb2	32.8 (10)	Rb1ⁱ—C1—O21—Na	−78.2 (5)
O11—C1—C2—Rb2	−145.6 (5)	Rb1—C1—O21—Na	124.2 (6)
Rb1ⁱ—C1—C2—Rb2	−69.9 (7)	O11—C1—O21—Rb1	−148.7 (5)
Rb1—C1—C2—Rb2	60.1 (5)	C2—C1—O21—Rb1	33.2 (6)
O21—C1—O11—Fe	−172.2 (5)	Rb1ⁱ—C1—O21—Rb1	157.58 (19)
C2—C1—O11—Fe	6.0 (6)	O11—C1—O21—Rb1ⁱ	53.7 (6)
Rb1ⁱ—C1—O11—Fe	−111.3 (3)	C2—C1—O21—Rb1ⁱ	−124.4 (6)
Rb1—C1—O11—Fe	107.9 (9)	Rb1—C1—O21—Rb1ⁱ	−157.58 (19)
O21—C1—O11—Rb1ⁱ	−60.9 (6)	O12—C2—O22—Rb1	157.6 (5)
C2—C1—O11—Rb1ⁱ	117.3 (4)	C1—C2—O22—Rb1	−21.9 (8)
Rb1—C1—O11—Rb1ⁱ	−140.8 (9)	Rb2—C2—O22—Rb1	−158.5 (8)
O21—C1—O11—Rb1ⁱⁱ	35.0 (9)	O12—C2—O22—Rb2	−43.9 (9)
C2—C1—O11—Rb1ⁱⁱ	−146.7 (4)	C1—C2—O22—Rb2	136.6 (5)
Rb1ⁱ—C1—O11—Rb1ⁱⁱ	96.0 (4)	Rb1—C2—O22—Rb2	158.5 (8)

Symmetry codes: (i) −z+1/2, −x+1, y−1/2; (ii) −x+1/2, −y+1, z−1/2; (iii) y−3/4, −x+1/4, z−1/4; (iv) −z, x+1/2, −y+1/2; (v) y−1/2, −z+1/2, −x; (vi) −y+3/4, −x+3/4, −z+3/4; (vii) −y+1, z+1/2, −x+1/2; (viii) −z+1/4, y−1/4, x+1/4; (ix) −x+1/2, −y+1, z+1/2; (x) y−1/4, x+1/4, −z+1/4; (xi) −y+1/2, −z+1, x+1/2; (xii) z−1/2, −x+1/2, −y+1; (xiii) −x−1/4, −z+3/4, −y+3/4; (xiv) −y+1/4, x+3/4, z+1/4; (xv) z−1/4, y+1/4, −x+1/4; (xvi) −x+3/4, −z+3/4, −y+3/4; (xvii) z+1/4, −y+5/4, x−1/4.

Funding information

Funding for this research was provided by: CONICET (PIP 11220130100651CO) and UNLP (Project 11/X709) of Argentina. OEP and GAE are Research Fellows of CONICET.

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