Unknown

Dataset Information

0

Oxo-Hydroxoferrate K2-x Fe4O7-x (OH) x : Hydroflux Synthesis, Chemical and Thermal Instability, Crystal and Magnetic Structures.

ABSTRACT: The reaction of Fe(NO3)3?9 H2O with KOH under hydroflux conditions at about 200?°C produces red crystals of K2-x Fe4O7-x (OH) x in a quantitative yield. In the crystal structure, edge-sharing [FeO6] octahedra form ?2[ Fe2O6] honeycomb nets. Pillars consisting of pairs of vertex-sharing [FeO4] tetrahedra link the honeycomb layers and form columnar halls in which the potassium ions are located. The trigonal (P 3? 1m) and the hexagonal (P63/mcm) polytypes of K2-x Fe4O7-x (OH) x show oriented intergrowth. The sub-stoichiometric potassium content (x?0.3) is compensated by hydroxide ions. K2-x Fe4O7-x (OH) x is an antiferromagnet above 2?K and its magnetic structure was determined by neutron powder diffraction. Under ambient conditions, K2-x Fe4O7-x (OH) x hydrolyzes and K2CO3???H2O forms gradually on the surface of the K2-x Fe4O7-x (OH) x crystals. Upon annealing at air at about 500?°C, the potassium atoms in the columnar halls start to order into a superstructure. The thermal decomposition of K2-x Fe4O7-x (OH) x proceeds via a topotactic transformation into K1+x' Fe11O17, adopting the rhombohedral ?'' or the hexagonal ?-aluminate-type structure, before ?-Fe2O3 is formed above 950?°C, which then converts into thermodynamically stable ?-Fe2O3.

SUBMITTER: Albrecht R 

PROVIDER: S-EPMC6345222 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

Json Xml
altmetric image

Publications

Oxo-Hydroxoferrate K<sub>2-<i>x</i></sub> Fe<sub>4</sub>O<sub>7-<i>x</i></sub> (OH) <sub><i>x</i></sub> : Hydroflux Synthesis, Chemical and Thermal Instability, Crystal and Magnetic Structures.

Albrecht Ralf R   Hunger Jens J   Block Theresa T   Pöttgen Rainer R   Senyshyn Anatoliy A   Doert Thomas T   Ruck Michael M  

ChemistryOpen 20190124 1

The reaction of Fe(NO<sub>3</sub>)<sub>3</sub>⋅9 H<sub>2</sub>O with KOH under hydroflux conditions at about 200 °C produces red crystals of K<sub>2-<i>x</i></sub> Fe<sub>4</sub>O<sub>7-<i>x</i></sub> (OH) <sub><i>x</i></sub> in a quantitative yield. In the crystal structure, edge-sharing [FeO<sub>6</sub>] octahedra form ∞ 2 [ Fe<sub>2</sub>O<sub>6</sub>] honeycomb nets. Pillars consisting of pairs of vertex-sharing [FeO<sub>4</sub>] tetrahedra link the honeycomb layers and form columnar ha  ...[more]

Similar Datasets

Unknown Crystal structures, and magnetic and thermal properties of basic copper formates with two-dimensional triangular-lattice magnetic networks.
| S-EPMC9086228 | biostudies-literature
Unknown Mesoporous single-crystal CoSn(OH)6 hollow structures with multilevel interiors.
| S-EPMC3589726 | biostudies-literature
Unknown Inorganic Phosphate and Arsenate within New Tetranuclear Copper and Zinc Complexes: Syntheses, Crystal Structures, Magnetic, Electrochemical, and Thermal Studies.
| S-EPMC6641055 | biostudies-literature
Unknown Accurate crystal structures and chemical properties from NoSpherA2.
| S-EPMC8179328 | biostudies-literature
Unknown Crystal structures of Z-Gly-Aib-O-·0.5Ca2+·H2O and Z-Gly-Aib-OH.
| S-EPMC6073005 | biostudies-literature
Unknown 3D Metal-Organic Frameworks Based on Co(II) and Bithiophendicarboxylate: Synthesis, Crystal Structures, Gas Adsorption, and Magnetic Properties.
| S-EPMC7956319 | biostudies-literature
Unknown Synthesis and crystal structures of three new benzotriazolylpropanamides.
| S-EPMC5458315 | biostudies-literature
Unknown Does the thermal evolution of molecular structures critically affect the magnetic anisotropy?
| S-EPMC5851079 | biostudies-literature
Unknown The crystal structures of four N-(4-halophen-yl)-4-oxo-4H-chromene-3-carboxamides.
| S-EPMC4331845 | biostudies-literature
Unknown Tin thiocarbonohydrazone complexes: synthesis, crystal structures and biological evaluation.
| S-EPMC7069364 | biostudies-literature