Synthesis of a Ferrolite: A Zeolitic All‐Iron Framework

Latshaw, Allison M.; Chance, W. Michael; Morrison, Gregory; Loye, Karl D. zur; Wilkins, Branford O.; Smith, Mark D.; Whitfield, Pamela S.; Kirkham, Melanie J.; Stoian, Sebastian A.; Loye, H.‐C. Zur

doi:10.1002/anie.201607800

Cited by 8 publications

(5 citation statements)

References 17 publications

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“…With alkaline earth metals, the oxoferrate(II,III) hydroxoferrate(III) Ba 4 [Fe 8 O 14 ][Fe(OH) 6 ] and the perovskite Ba[FeO 2.5−x (OH) 2x ], were described. Highly remarkable is the mixed‐metal oxoferrate(III) hydroxide Ba 8 (Fe 12 O 24 )Na y (OH) 6 ⋅ x H 2 O, which is a zeolitic framework of iron‐centered tetrahedra hosting hydroxide ions and counter cations in its channels.…”

Section: Introductionmentioning

confidence: 99%

Antiferromagnetic Alkali Metal Oxohydroxoferrates(III) with Correlated Hydrogen Bonding Systems

et al. 2019

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The oxohydroxoferrates(III) A 2 [Fe 2 O 3 (OH) 2 ] (A = K, Rb, Cs) were synthesized under hydroflux conditions. Approximately equimolar mixtures of the alkali metal hydroxides and water were reacted with Fe(NO 3 ) 3 · 9H 2 O at about 200°C. The product formation depends on the hydroxide concentration, therefore also other reaction products, such as KFeO 2 , K 2À x [Fe 4 O 7À x (OH) x ] or α-Fe 2 O 3 , are obtained. The crystal structures of the oxohydroxoferrates(III) A 2 [Fe 2 O 3 (OH) 2 ] follow the same structural principle, yet differ in their layer stacking or/and their hydrogen bonding systems depending on A and temperature. In the resulting four different orthorhombic structure types, [FeO 3 OH] 4À tetrahedra share their oxide corners to create folded 1 2 ½Fe 2 O 3 (OH) 2 ] 2À layers. The terminal hydroxide ligands form hydrogen bonds between and/or within the layers. The positions of the hydrogen atoms in these networks are correlated. The A + cations are located between the folded anionic layers as well as in their trenches. Under reaction conditions, the potassium compound crystallizes in the space group Cmce (Pearson symbol oC88), showing a bimodal disorder of the hydrogen atoms in hydrogen bridges. In a virtually hysteresis-less first-order transition at 340(2) K, the structure slightly distorts into the room-temperature modification with the subgroup Pbca (oP88), and the hydrogen atoms order. The rubidium and caesium compounds are isostructural to each other but not to the potassium compound, and are always obtained as mixtures of two modifications with space groups Cmce (oC88') and Immb (oI88). Upon heating, the oxohydroxoferrates decompose into their anhydrides AFeO 2 and water. The type of hydrogen bonding network influences the decomposition temperature, the structure and the morphology of the crystals. Despite the presence of iron(III), which was confirmed by 57 Fe-Mössbauer spectroscopy, K 2 [Fe 2 O 3 (OH) 2 ] is diamagnetic in the investigated temperature range between 1.8 and 300 K. Neutron diffraction revealed strong antiferromagnetic coupling of the magnetic moments, which are inverted in neighboring tetrahedra.

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Section: Introductionmentioning

confidence: 99%

Antiferromagnetic Alkali Metal Oxohydroxoferrates(III) with Correlated Hydrogen Bonding Systems

et al. 2019

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“…Fe( 1) is coordinated to O(1), O(2), O(4), and O(6) in a tetrahedral environment with bond lengths of 1.8564, 1.831(5), 1.831(4), and 1.837(4) Å, respectively. A similar tetrahedral environment is exhibited by Fe(2), which is coordinated to O(3), O(5), O (7), and O(8) with bond lengths 1.835(4), 1.826(3), 1.861(5), and 1.856(5) Å, respectively. These bond lengths are in fair agreement with the Fe−O bond lengths ranging from 1.828 Å−1.896 Å in Ba 4 KFe 3 O 9 , 41 which contains discrete 6membered rings of corner-sharing FeO 4 tetrahedra, as well as other compounds containing iron in tetrahedral, noncentrosymmetric environment.…”

Section: ■ Results and Discussionmentioning

confidence: 79%

“…Zeolites are a naturally occurring class of microporous, crystalline aluminosilicates that are produced commercially for their use in catalysis, gas adsorption, and ion-exchange applications. − Modifying aluminosilicates by introducing transition elements has always been of interest; however, attempts to incorporate, for example, iron into the aluminosilicate framework via hydrothermal routes have been met with limited success. − Nonetheless, the growth of single crystals of the first sodalite-type zeolite containing an all-iron framework, a ferrolite, Ba 8 (Fe 12 O 24 )Na y (OH) 6 · x H 2 O, was recently reported using a modified hydrothermal method, the hydroflux method, in nearly quantitative yield . Achieving tetrahedral Fe(III) coordination in a normal hydrothermal environment appears difficult and is likely the chief impediment to the formation of iron-based zeolite-type, three-dimensional porous frameworks.…”

Section: Introductionmentioning

confidence: 99%

“…4−6 Nonetheless, the growth of single crystals of the first sodalite-type zeolite containing an all-iron framework, a ferrolite, Ba 8 (Fe 12 O 24 )Na y (OH) 6 •xH 2 O, was recently reported using a modified hydrothermal method, the hydroflux method, in nearly quantitative yield. 7 Achieving tetrahedral Fe(III) coordination in a normal hydrothermal environment appears difficult and is likely the chief impediment to the formation of iron-based zeolite-type, threedimensional porous frameworks.…”

Section: ■ Introductionmentioning

confidence: 99%

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Polymorphism and Molten Nitrate Salt-Assisted Single Crystal to Single Crystal Ion Exchange in the Cesium Ferrogermanate Zeotype: CsFeGeO₄

et al. 2020

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Two polymorphs of a new cesium ferrogermanate zeotype, CsFeGeO4, were synthesized using the molten CsCl-CsF flux growth approach at 900 °C. The orthorhombic polymorph, referred to as (1), crystallizes in the centrosymmetric nonpolar Pbcm space group. The compound exhibits a three-dimensional porous framework structure composed of disordered (Fe/Ge)O4 corner-sharing tetrahedra that generate large eight-sided channels running down the b-axis. These channels are occupied by Cs ions that provide charge balance to the anionic framework. Minor modifications in the reaction conditions lead to the synthesis of a monoclinic polymorph of CsFeGeO4, referred to as (2), crystallizing in the noncentrosymmetric polar space group P21 and exhibiting an identical framework structure to (1), albeit featuring ordered FeO4 and GeO4 tetrahedra. Solid state synthesis of CsFeGeO4 produces a polycrystalline mixture of (1) and (2), referred to as (6). Polarization-electric field (P-E) measurements of (6) indicate that the material is not ferroelectric. Powder second harmonic generation (SHG) measurements of (2) and (6) revealed them to be SHG active with intensities of 1.5 and 0.2 times that of α-SiO2, respectively. The temperature dependent magnetic susceptibility of (2) exhibits a downturn at T = 2.6 K, indicative of antiferromagnetic ordering. First-principles calculations in the form of density functional theory showed that (1) and (2) differ in stability by only 1.3 meV/atom, with (2) being the thermodynamically stabilized phase. Additional calculations for (1), using molten nitrate as reference, predicted the formation of energetically favorable phases, KFeGeO4 (3) and RbFeGeO4 (4). They were subsequently prepared via a molten nitrate salt bath treatment of (1) to replace Cs with K and Rb, affording (3) and (4) as single-crystal to single-crystal ion exchange products. Structure determination and property measurements for a pyroxene phase, CsFeGe2O6, referred to as (5), are also reported. This compound crystallized as a side product in the flux synthesis of CsFeGeO4.

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“…The work of zur Loye [15,16,[19][20][21][22][23][24][25][26][27][28] and the recent contributions by us [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] give an impression of the potential of the hydroflux method. In just a few years, almost 100 new compounds were found in already extensively explored systems.…”

Section: Introductionmentioning

confidence: 99%

Oxohydroxo‐Tellurates(VI) K₂[TeO₂(OH)₄] and K₂[Fe₂TeO₆(OH)₂] ⋅ 2H₂O from Alkaline Hydroflux

He,

Li,

Albrecht

et al. 2023

Zeitschrift anorg allge chemie

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The ultra‐alkaline conditions of a hydroflux offer the possibility of redox chemistry far from the electrochemical standard potentials. We explored the possibilities of synthesizing tellurium(VI) compounds, using both tellurium(VI) and tellurium(IV) as starting materials. Colorless, block‐shaped crystals of the oxohydroxotellurate(VI) K2[TeO2(OH)4] were synthesized from (NH4)2TeO4 in a KOH hydroflux at 200 °C. In the triclinic crystal structure, [TeO2(OH)4]2− octahedra are connected via hydrogen bonds to form layers, which are separated from each other by potassium cations. Yellow‐colored platelets of the ferrate(III) tellurate(VI) K2[Fe2TeO6(OH)2] ⋅ 2H2O were obtained by oxidation of TeO2 with H2O2 followed by reaction with Fe(NO3)3 ⋅ 9H2O in a KOH hydroflux. In the monoclinic crystal structure, strongly corrugated anionic layers Fe2TeO6(OH)2]2− are covered with water molecules and separated from each other by potassium cations. The octahedrally coordinated iron(III) atoms form a distorted honeycomb network, in which they are antiferromagnetically coupled at room temperature and in external fields up to at least 7 T.

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Synthesis of a Ferrolite: A Zeolitic All‐Iron Framework

Cited by 8 publications

References 17 publications

Antiferromagnetic Alkali Metal Oxohydroxoferrates(III) with Correlated Hydrogen Bonding Systems

Antiferromagnetic Alkali Metal Oxohydroxoferrates(III) with Correlated Hydrogen Bonding Systems

Polymorphism and Molten Nitrate Salt-Assisted Single Crystal to Single Crystal Ion Exchange in the Cesium Ferrogermanate Zeotype: CsFeGeO₄

Oxohydroxo‐Tellurates(VI) K₂[TeO₂(OH)₄] and K₂[Fe₂TeO₆(OH)₂] ⋅ 2H₂O from Alkaline Hydroflux

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Synthesis of a Ferrolite: A Zeolitic All‐Iron Framework

Cited by 8 publications

References 17 publications

Antiferromagnetic Alkali Metal Oxohydroxoferrates(III) with Correlated Hydrogen Bonding Systems

Antiferromagnetic Alkali Metal Oxohydroxoferrates(III) with Correlated Hydrogen Bonding Systems

Polymorphism and Molten Nitrate Salt-Assisted Single Crystal to Single Crystal Ion Exchange in the Cesium Ferrogermanate Zeotype: CsFeGeO4

Oxohydroxo‐Tellurates(VI) K2[TeO2(OH)4] and K2[Fe2TeO6(OH)2] ⋅ 2H2O from Alkaline Hydroflux

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Resources

About

Polymorphism and Molten Nitrate Salt-Assisted Single Crystal to Single Crystal Ion Exchange in the Cesium Ferrogermanate Zeotype: CsFeGeO₄

Oxohydroxo‐Tellurates(VI) K₂[TeO₂(OH)₄] and K₂[Fe₂TeO₆(OH)₂] ⋅ 2H₂O from Alkaline Hydroflux