Neue Oxoferrate(III). Na2Li3[FeO4] und K2Li3[FeO4]

New Oxoferrates (III). Na₂Li₃[FeO₄] and K₂Li₃[FeO₄] . Na₂Li₃[FeO₄] and K₂Li₃[FeO₄] (transparent, pink or light yellow single crystals) have been prepared by heating mixtures of the oxides (Na:Li:Fe = 2.2:3.3:1; Ag-tube, 720°C, 27 d or K:Li:Fe = 2.2:3.3:1; analogous, 700°C, 40 d). Na₂Li₃[FeO₄] is isotypic with Na₂Li₃[GaO₄] (a = 832.2(1), b = 796.0(1), c = 656.3(1)pm, Pnnm) and K₂Li₃[FeO₄] with K₂Li₃[GaO₄] (a = 557.7(1), b = 880.6(1), c = 1101.8(2)pm, β = 111.51(2)°, P2₁/c). Four cycle diffractometer data: MoK_α, 525 out of 686 I₀(hkl), R = 9.36%, R_w = 5.97% or 1424 out of 1424 I₀(hkl), R = 8.45%, R_w = 5.66%. Parameters see text. The structures are characterized by calculations of the Madelung Part of Lattice Energy, MAPLE. The Effective Coordination Numbers, ECoN, which are calculated by means of Mean Fictive Ionic Radii, MEFIR, are compared with the analogous gallates.     

Über Oxide mit dem “Butterfly-Motiv”: Rb6[Fe2O5] und K6[Fe2O5]

New Oxides with the “Butterfly-Motive”: Rb₆[Fe₂O₅] and K₆[Fe₂O₅] Rb₆[Fe₂O₅] and K₆[Fe₂O₅] were obtained for the first time by annealing intimate mixtures of “Rb₆CdO₄” with CdO (molar ratio 1 : 1.1) and KO_0.48 with CdO (molar ratio 5.9 : 1) respectively in closed Fe-cylinders. Determination and refinement of the crystalstructure confirms the space group C2/m (four-circle-diffractometer data). Rb₆[Fe₂O₅]: Ag Kα , 720 out of 1220 Io(hkl), R = 9.68%, R_w = 6.09%; a = 718.9pm, b = 1183.1 pm, c = 695.4pm, β = 95.05°, Z = 2; K₆[Fe₂O₅]: MoKα , 1214 Out of 12141_o(hkl), R = 3.20070, R_w = 2.48%, a = 691.21 pm, b = 1142.78pm, c = 665.50pm, β = 93.82°, Z = 2. The binuclear unit [O₂FeOFeO₂]^6? already known to be planar with oxoferrates(II) now was observed to be angular here and closely related to Na₆[Be₂O₅].     

Zur Konstitution von Cs2[FeO4]

On the Constitution of Cs₂[FeO₄] For the first time black, spherical single crystals of Cs₂[FeO₄] were prepared by an “oxydative exchange reaction” of NaFeO₂ with CsO_1,8 (molar ratio Fe:Cs = 1.00:2.10, Au-tube, 250°C 3d, 480°C 24d, 360°C 5d): Spacegroup Pnma with a = 842.86(12) pm, b = 628.12(10) pm, c = 1105.33(17) pm. Cs₂[FeO₄] is isotypic to β-K₂SO₄. The structure was determined by four circle diffractometer data [MoKα , 1384 of 1387 I_o(hkl), R = 3.36%, R_w = 3.08%]; parameters as given in the text. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, and the Charge-distribution will be calculated and discussed.     

Neue Oxozincate mit Inselstruktur: K4[ZnO3] Mit einem Anhang über Rb7Na[ZnO3]2

New Nesozincates: K₄[ZnO₃], Rb₇Na[ZnO₃]₂ For the first time A) K₄[ZnO₃] and B) Rb₇Na[ZnO₃]₂ have been prepared (from the binary oxides). They represent the first oxozincates of the alkali metals in which the coordination number of Zn²⁺ is exclusively 3 (carbonate-like groups [ZnO₃]). Both oxides crystallize triclinic, space group P1 with A): a = 1103.3(3), b = 881.3(3), c = 698.2(2) pm, α = 109.65(2)°, β = 89.56(2)°, γ = 102.41(3)° and Z = 4, and B): a = 1128.3(3), b = 974.5(3), c = 711,8(2) pm, α = 114.12(2)β, = = 88.46(3)°,γ = 106.48(2)° and Z = 4. Their crystal structures have been determined from single crystal data (four circle diffractometer) and refined to R = 10.1%, R_w = 7.8% (2905 unique I₀(hkl)) and R = 19.5%, R_w = 17.3% (2269 unique I₀(hkl)), respectively. The Madelung Part of Lattice Energy (MAPLE), Effective Coordination Numbers (ECoN) and Mean Fictive Ionic Radii (MEFIR) have been calculated.     

Die ersten Oxocobaltate(II) mit zweikernigem Anion: Rb2Na4[Co2O5] und K2Na4[Co2O5]

The First Oxocobaltate(II) with Dinuclear Anion: Rb₂Na₄[Co₂O₅] and K₂Na₄[Co₂O₅] By heating of well ground mixtures of the binary oxides [A₂O, Na₂O, ?CoO”?, A:Na:Co = 1.00:2.00:1, (A = K, Rb); Ag-tube, 600°C, 14 d] we obtained Rb₂Na₄[Co₂O₅] and K₂Na₄[Co₂O₅] rough, transparent, red single crystals. We find a new type of structure with the anion [O₂CoOCoO₂]^6?. Space group P4₂/mnm; a = 634.4 pm, c = 1030.3 pm, Z = 2 (A = K) a = 647.6 pm, c = 1021.1 pm, Z = 2 (A = Rb); four-circle diffractometer data; MoKα -radiation; 360 from 364 I₀(hkl), R = 4.34%, R_w = 3.54% (A = K); 361 from 366 I₀(hkl), R = 6.54%, R_w = 2.70% (A = Rb). The anion is planar, the CN of Co is 3. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, are calculated and discussed.     

Das gemischtvalente ternäre Oxoferrat(II,III) K3[Fe2O4] – eine aufgefüllte Variante des K2[Fe2O4]‐Typs

The Mixed‐Valent Oxoferrate(II,III) K₃[Fe₂O₄] – A Stuffed Variant of the K₂[Fe₂O₄] Type of Structure K₃[Fe₂O₄] has been obtained by tempering “Cs₃K₃CdO₄” in sealed Fe containers (36 d at 450–480 °C) as dark red transparent single crystals of rectangular shape. The structure determination (IPDS diffractometer data, MoKα, 1891 collected reflections, 234 symmetry independent, R1 = 0.033, wR2 = 0.088) confirms the space group Fddd; a = 596.11(9), b = 1140.3(1), c = 1717.9(3) pm; Z = 8. K₃[Fe₂O₄] exhibits a structure with [FeO₄] tetrahedra connected via corners leading to a three‐dimensional network closely related to the KFeO₂ type of structure. From the oxidation at 520 °C of iron metal with KO₂ in the presence of Na₂O black single crystal of K₂[Fe₂O₄] have been obtained. K₂[Fe₂O₄] crystallizes in the space group Pbca with Z = 8 and a = 559.18(7), b = 1122.1(1), c = 1592.8(2) pm (IPDS diffractometer data, MoKα, collected refelctions: 9543, 1213 symmetry independent, R1 = 0.043, wR2 = 0.102).     

Darstellung und Kristallstruktur von K6[Al2O6] und Rb6[Al2O6]

Preparation of Crystal Structure of K₆[Al₂O₆] and Rb₆[Al₂O₆] Colourless single crystals of K₆[Al₂O₆] have been prepared from intimate mixtures of KAlO₂ and K₂O (550°C, 90 d). The structure determination from four-circle diffractometer data (MoKα , 742 I_o(hkl), R = 2.2%, R_w = 2.1%) confirms the space group C2/m with Z = 2; a = 698.25 pm, b = 1 103.54 pm, c = 646.49 pm, β = 102.49°. Colourless single crystals of hitherto unknown Rb₆[Al₂O₆] have been prepared from intimate mixtures of RbAlO₂ and Rb₂O (520°C, 120 d). The structure determination from four-circle diffractometer data (MoKα , 1 240 I_o(hkl)) results in the residual values R = 7.2%, R_w = 4.9%; space group C2/m; a = 725.92 pm, b = 1 143.33 pm, c = 678.06 pm, β = 104.05°; Z = 2. K₆[Al₂O₆] and Rb₆[Al₂O₆] are isostructural with K₆[Fe₂O₆]. A characteristic structure unit is the anion [Al₂O₆]^6? consisting of two edge-sharing [AlO₄] tetrahedra. Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR), the Madelung Part of Lattice Energy (MAPLE) and the Charge Distribution (CHARDI) are calculated and discussed.     

Ein neues Inoferrat(III): K2 Na4[(FeO3)2]

A New Inoferrate(III): K₂Na₄[(FeO₃)₂] For the first time amber coloured single crystals of K₂Na₄[(FeO₃)₂] were prepared by heating well ground mixtures of KFeO₂ and Na₂O (molar ratio Na₂O:KFeO₂= 1.4:1.0; ?Ag-tube”?, 500 °C/29 d, 400 °C/5 d): Spacegroup Pnma with a = 650.50(6) pm, b = 619.62(5) pm, c = 1020.64(12) pm. K₂Na₄[(FeO₃)₂] is isotypic to K₂Na₄[(GaO₃)₂] [2]. The structure has been determined by four-circle-diffractometer data [Mo—Kα , 982 of 982 unique I₀(hkl), R = 4.56%, R_w = 4.56% (no weight)]; parameters as given in the text. The Madelung Part of Lattice Energy, MAPLE, and the Effective Coordination Number, ECoN, these via Mean Fictive Ionic Radii, MEFIR will be calculated and discussed.     

Neue Vertreter des K2Li14[Pb3O14]-Typs Cs2Li14[Tb3O14] und K2Li14[Zr3O14] [1, 2]

Inhaltsübersicht. Erstmals wurden klar durchscheinende, orange-farbene Einkristalle von Cs₂Li₁₄[Tb₃O₁₄] aus Cs₂TbO₃ und Li₂O (Tb: Li = 1:5) dargestellt [550°C, 21 d, verschlossenes AuRohr]. Es liegt der K₂Li₁₄[Pb₃O₁₄]-Typ vor [Vierkreisdiffraktometerdaten, PW 1100, MoKä-Strahlung, 660 I_o(hkl), R = 4,8%, R_w = 3,4%, Immm, a = 1293,5(8), b = 792,6(3), c = 740,4(3) pm, Z = 2, d_rö = 4,65]. Ebenfalls neu wurde K₂Li₁₄[Zr₃O₁₄] in Form farbloser Einkristalle durch Tempern inniger Gemenge von K₂O, Li₂O und ZrO₂ (K: Li: Zr = 1:4:1,5) dargestellt [900°C, 14 d, geschlossene Ni-Bombe] und röntgenographisch untersucht. Die Strukturverfeinerung [612 I_o(hkl), Vierkreisdiffraktometerdaten, PW 1100, MoKα-Strahlung, R = 5,9%, R_w = 5,3%, Immm, a = 1244,6, b = 776,4, c = 724,3 pm, Z = 2] bestätigt die Isotypie mit K₂Li₁₄[Pb₃O₁₄]. Der Madelunganteil der Gitterenergie, MAPLE, Effektive Koordinationszahlen, ECoN, diese über Mittlere Effektive Ionenradien, MEFIR, wurden berechnet. Für die nun bekannten Vertreter dieses Typs wurde ein Isotypievergleich vorgenommen. New Compounds of the K₂Li₁₄[Pb₃O₁₄] Type: Cs₂Li₁₄[Tb₈O₁₄] and K₂Li₁₄[Zr₃O₁₄] For the first time Cs₂Li₁₄[Tb₃O₁₄] has been prepared as orange single crystals from Cs₂TbO₃ and Li₂O (Tb: Li = 1:5) [550°C, 21 d, sealed Au-Tube]. Structure Refinement [four-circle diffractometer data, PW 1100, MoKα radiation, 660 I_o(hkl), R = 4.8%, R_w = 3.4%, Immm, a = 1293.5(8), b = 792.6(3), c = 740.4(3) pm, Z = 2, d_rö = 4.65] confirms isotypy with K₂Li₁₄[Pb₃O₁₄]. K₂Li₁₄[Zr₃O₁₄] has also been prepared as colorless single crystals from K₂O, Li₂O, and ZrO₂ (K: Li: Zr = 1:4:1.5), [900°C, 14 d, closed Ni-cylinder] and investigated by x-ray [612 I_o(hkl), four-circle diffractometer data, PW 1100, MoKα radiation, R = 5.9%, R_w = 5.3%, Immm, a = 1244.6, b = 776.4, c = 724.3 pm, Z = 2]. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, the latter derived from Mean Effective Fictive Ionic Radii, MEFIR, are calculated. A detailed comparison of the structures is carried out.     

Über ein neues Oxoferrat mit „Butterfly-Motiv”︁: K2Na4[Fe2O5]

A New Oxoferrate with “Butterfly-Motiv”: K₂Na₄[Fe₂O₅] Dark red-brown single-crystals of K₂Na₄[Fe₂O₅] were obtained for the first time by heating “K₃Na₃CdO₄” at 500°C in closed Fe-cylinders. Determination and refinement of the crystal structure confirms the space group P4₂/mnm (No. 136). Four-circle diffractometer data: MoKα , 373 out of 373 I_o(hkl); R = 5.3%; R_w = 4.6%; a = 645.94(5), c = 1 039.2(1) pm. In contrast to the already known oxoferrates(II) with the “Butterfly-Motiv”, Rb₆[Fe₂O₅] and K₆[Fe₂O₅] [1], we now found an isotypic structure for K₂Na₄[Fe₂O₅] with the oxocobaltates of Rb₂Na₄[Co₂O₅] and K₂Na₄[Co₂O₅] [2].     

Neue Oxocadmate der Alkalimetalle: K6[CdO4],Rb6[CdO4], Rb2CdO2 und Rb2Cd2O3

The crystal structure of K₆[CdO₄] and Rb₂CdO₂ has been determined from single crystal X-ray diffraction data and refined toR=0.058 (K₆[CdO₄]) andR=0.088 (Rb₂CdO₂). K₆[CdO₄] crystallizes hexagonal, space group P6₃mc with lattice constantsa=867.42 (6),c=665.5 (1) pm,c/a=0.767 andZ=2. It is isotypic with Na₆[ZnO₄]. Rb₂CdO₂ is orthorhombic, space group Pbcn witha=1045.0 (2),b=629.1 (1),c=618.3 (1) pm,Z=4, and crystallizes with the K₂CdO₂ structure type. The crystal structures can be deduced from the motif of a closest packed arrangement of O^2– with hexagonal (K₆[CdO₄]) or cubic (Rb₂CdO₂) stacking. The tetrahedra occupied by Cd²⁺ are isolated (K₆[CdO₄]) or edge-shared (formation of infinite SiS₂-like chains [CdO_4/2]) (Rb₂CdO₂). The powder diffraction pattern of Rb₆[CdO₄] [a=906.6 (1),c=694.3 (1) pm] and Rb₂Cd₂O₃ [a=642.6 (2),b=679.0 (1),c=667.9 (2) pm, =115.2 (1)] confirm isotypie with K₆[CdO₄] and K₂Cd₂O₃ respectively.

Herrn Prof. Dr.Gutman zum 65. Geburtstag gewidmet.     

Zur Konstitution von Alkaliperoxotantalaten(V): Über den Aufbau von K3[Ta(O2)4]

On the Constitution of Peroxotantalates(V) with Alkali Metals: On the Structure of K₃[Ta(O₂)₄] [1] By solving of recently precipitated Ta₂O₅ · aq in a 1.5-molar solution of KOH in 3% H₂O₂ and subsequently cooling at 0°C we obtained colourless single-crystals of K₃[Ta(O₂)₄]. The compound crystallizes tetragonal (spacegroup 142m) with a = 679.5(1) pm, c = 791.2(1) pm, Z = 2 (Guinier-de-Wolff powder data). The determinated crystal structure (four-circle diffractometer, 444 out of 444 I₀(hkl); R = 1.51%, R_w = 1.48%, parameters see text) proves that K₃[Ta(O₂)₄] is isotypic with K₃[Cr(O₂)₄] [2]. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these calculated via Mean Fictive Ionic Radii, as well as charge distribution (CHARDI) are calculated and discussed.     

Oxydation intermetallischer Phasen: CsK2[AuO2] aus CsAu + K2O2

Oxidation of Intermetallic Phases CsK₂[AuO₂] from CsAu+K₂O₂ We prepared the hitherto unknown CsK₂[AuO₂] [Heating mixtures of CsAu and K₂O_2,2; 1:1; gives single crystals (Ag-cylinder, 430°C, 6d)]. The single crystals are light blue, nearly colourless, and transparent. A new type of structure is found. The single crystal data are: Pnma; a = 1256.5(5), b = 727.3(2), c = 627.9(2)pm, Z = 4; four-circle diffractometer PW 1100, MoKα;849 out of 871 I₀(hkl), R = 7.3% and R_w = 6.3%. The Madelung Part of Lattice Energy, MAPLE, is calculated.     

Ein neues Oxoindat K2Na3[InO4]

A New Oxoindate K₂Na₃[InO₄] We prepared the hitherto unknown K₂Na₃[InO₄] on two different ways as single crystals

• a) by heating mixtures of In₂O₃, NaO_0.48 and KO_0.60 (In:Na:K = 1:3.3:2.2) [Ag-cylinder, 580°C, 42 d].
• b) by the oxidation of NaIn with Na₂O₂ and KO_0.87 (In:Na:K = 1:2:6) [Ag-cylinder, 480°C, 8 d].

The single crystals of K₂Na₃[InO₄] are colourless, all transparent and rough. The type of structure was elucidated by 4-circle diffractometer (Siemens AED 2) data: Pnnm; a = 955.5(4), b = 927.6(4), c = 753.4(2) pm; Z = 4; MoKα; 909 of 1031 I₀(hkl); R = 9.7%, R_w = 3.9%. The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

Das erste Oxid vom Formeltyp K5[MO4]: K5[TIO4] [1]

The First Oxide with the Formula Type K₅[MO₄]: K₅[TlO₄] Light yellow powder and pale yellow transparent single crystals of K₅[TlO₄] were newly prepared from mixtures of binary oxides (K₂O/Tl₂O₃) preheated and levigated several times [closed Ag-cylinder, 580°C, 24 h and 600°C, 20 d]. Space group Pbca with a = 1170.4(3), b = 686.1(1), c = 2079.2(5) pm, Z = 8 [four-circle-diffraktometer data, 997 I₀(hkl), R = 7.87%, R_w = 5.63%, MoKα] (parameter s. text). The crystal structure belongs to the Na₅[GaO₄] type. Structural aspects, ECoN and MAPLE are discussed.     

Ein neues Oxoberyllat: K2Na4[O2BeOBeO2]

On K₂Na₄[O₂BeOBeO₂] For the first time colourless single crystals of K₂Na₄[Be₂O₅] which are isotypic with K₂Na₄[Co₂O₅] [2] and Rb₂Na₄[Co₂O₅] have been prepared by heating e.g. a well ground mixture of K₂O, Na₂O and BeO (K:Na:Be = 2.2:4.4:2; 750°C; 21 d; Ni-tube). The crystal structure was solved by four-circle diffractometer data [Siemens AED 2; 389 I_o(hkl); space group P4₂/mnm; Z = 2; a = 595.17(4) pm, c = 1 002.66(9) pm; R = 4.1%; R_w = 2.3%]. Mean Fictive Ionic Radii, MEFIR, Effective Coordination Numbers, ECoN, the Madelung Part of Lattice Energy, MAPLE, and the charge distribution are calculated.     

Synthese,Kristallstrukturen und Absorptionsspektren der neuen „Cupriosilicate”︁: K6[CuSi2O8] und Rb4[CuSi2O7]

Synthesis, Crystal Structures, and Absorption Spectra of the New “Cupriosilicates”: K₆[CuSi₂O₈] and Rb₄[CuSi₂O₇] K₆[CuSi₂O₈] and Rb₄[CuSi₂O₇] were obtained by annealing intimate mixtures of K₂O and Rb₂O, respectively, CuO and SiO₂ in sealed Ag cylinders at 500°C as transparent greenish-blue single crystals. The structure solution (IPDS-data Mo Kα; K₆[CuSi₂O₈]: 1292 F²(hkl), R1 = 0.059; wR2 = 0.103 and Rb₄[CuSi₂O₇]: 763 F²(hkl), R1 = 0.049; wR2 = 0.114) confirms the space group P1 for both compounds. K₆[CuSi₂O₈]: a = 619.4(2); b = 665.5(2); c = 753.0(2) pm; α = 83.66(3); β = 87.71(3); γ = 70.19(3)°; Z = 1. Rb₄[CuSi₂O₇]: a = 631.9(9); b = 707.5(10); c = 715.2(6) pm; α = 114.2(1); β = 100.7(1); γ = 107.9(1)°; Z = 1. The Madelung Part of the Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these calculated via Mean Effective Ionic Radii, MEFIR, are given. The absorption spectra of K₆[CuSi₂O₈] and Rb₄[CuSi₂O₇] are discussed in terms of the Angular Overlap Model, AOM.     

Das erste oligomere Oxoindat(III): K14[In4O13]

The First Oligooxoindate(III): K₁₄[In₄O₁₃] For the first time K₁₄[In₄O₁₃] was obtained by heating intimate mixtures of K₂O, CdO and elementar In (molar ratio 3.1:1.0:1.0) in closed Ag-cylinders (30 days, 450°C) in form of yellow-brown single crystals. The structure determination by four circle diffractometer data MoKα, 3 689 out of 3 689 I_o(hkl), R = 4.22, R_w = 2.45) confirms the space group P2₁/c with lattice constants a = 687.7 pm; b = 3 118.5 pm; c = 686.4 pm; β = 119.3°; Z = 2. The characteristic feature of the structure is [In₄O₁₃]^14? groups, oligomers consisting of four corner-sharing InO₄ tetrahedra. These groups are connected by crystallographically distinct potassium atoms. The structure is isotypic with Na₁₄[Al₄O₁₃] [2] and K₁₄[Fe₃O₁₃] [3]. ECoN and MAPLE calculationes are discussed.     

Über „Lithovanadate”︁: Zur Kenntnis von Rb2[LiVO4] und Cs2[LiVO4]

On ?Lithovanadates”?: Rb₂[LiVO₄] and Cs₂[LiVO₄] By heating of well ground mixtures of the binary oxides [A₂O, Li₂O, V₂O₅, A : Li: V = 2.2 : 1.1 : 1.0 (A = Rb, Cs); Ni-tube, 750° 25 d] we obtained Rb₂[LiVO₄] and Cs₂[LiVO₄] colourless, orthorhombic single crystals. We found a new type of ?Lithovanadate”?-structure: space group Cmc2₁; a = 587.9(1), b = 1170.1(1), c = 793.3(1) pm, Z = 4 (A = Rb) bzw. a = 610.5(1), b = 1222.6(3), c = 815.5(2) pm, Z = 4 (A = Cs). The structure was determined by four-circle diffractometer data [MoKα -radiation; 997 from 1157 I₀(hkl), R = 7.75%, R_w = 5.54% (A = Rb); 686 from 686 I₀(hkl), R = 6.97%, R_w = 4.20% (A = Cs)] parameters see text. The Madelung part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, have been calculated.     

Na9[FeO3][FeO4] ein gemischtvalentes Oxoferrat(II,III) mit isolierten [FeO3]4— — und [FeO4]5— ‐Anionen

Na₉[FeO₃][FeO₄]a Mixed Valent Oxoferrat(II, III) with Isolated [FeO₃]^4— — and [FeO₄]^5— Anions Na₉[FeO₃][FeO₄] has been formed and obtained from a redox reaction between CdO and iron metal (reaction container) and Na₂O in the presence of NaOH at 450 °C as orange‐red transparent single crystals. The crystal structure determination (IPDS data: Pca2₁, a = 956.2(2) pm, b = 999.1(2) pm, c = 1032.3(2) pm, Z = 4, R_all = 0.0455) reveals the presence of isolated complex anions, [FeO₃]^4— and [FeO₄]^5—.