The Hydrogarnets Sr₃[RE(OH)₆]₂ (RE = Sc, Y, Ho – Lu): Syntheses, Crystal Structures, and their Thermal Decomposition to Ternary Rare‐Earth Metal Oxides

Abstract

Seven rare-earth metal hydrogarnets Sr 3 [RE(OH) 6 ] 2 (RE = Sc, Y, Ho-Lu) were synthesized at about 200°C starting from the respective RE 2 O 3 and Sr(NO 3) 2 in a KOH hydroflux with a water-tobase ratio of 1.6. All seven hydrogarnets crystallize in the acentric variant (space group I43d) of the cubic garnet structure. The crystal structures of the hydrogarnets Sr 3 [RE(OH) 6 ] 2 , the differences between both structural variants including a simple method to distinguish between them, and the crystal-chemical classification with respect to other known strontium hydrogarnets are discussed. The rare-earth hy

Hydroflux synthesis and crystal structure of Tl3IO

“…For the synthesis of the title compound, the hydroflux method was used, which can be classified as intermediate between hydrothermal and flux synthesis (Chance et al, 2013). An approximately equimolar mixture of alkali-metal hydroxide (typically NaOH or KOH) and water is used as reaction medium (Albrecht et al, 2020a). Good solubility of oxides and hydroxides, highly crystalline reaction products suitable for single-crystal X-ray diffraction analysis, comparably low reaction temperatures and a pressureless setup are essential advantages of the hydroflux method.…”

Hydrothermal Synthesis, Crystal Structure, and Magnetism of Na2[Ir(OH)6] and its Dehydration to Na2IrO3

“…The hydrothermal method is especially suitable for oxides and hydroxides, although the parameter space is large and products of such reactions are sometimes difficult to predict [17] . For the synthesis of Na 2 [Ir(OH) 6 ], we used higher concentrated solutions, inspired by the hydroflux method, [10] which provides a greater solubility of oxides/hydroxides, excellent yields of highly crystalline products and single‐crystals suitable for X‐ray structure analysis [18–20] …”

“…[17] For the synthesis of Na 2 [Ir(OH) 6 ], we used higher concentrated solutions, inspired by the hydroflux method, [10] which provides a greater solubility of oxides/hydroxides, excellent yields of highly crystalline products and single-crystals suitable for X-ray structure analysis. [18][19][20] Yellow hexagonal plates of Na 2 [Ir(OH) 6 ] ( Figure 1) were synthesized under hydrothermal conditions in a 20 m sodium hydroxide solution. The reaction was carried out in a PTFE-lined stainless steel autoclave to prevent water loss and due to the high corrosiveness of the reaction medium.…”

Ba3[Rh(OH)6]2 ⋅ H2O – a Precursor to Barium Oxorhodates with One‐dimensional Hydrogen Bonding Systems

“…[10][11][12][13] The hydroflux method is known for excellent yields of highly crystalline products with large single-crystals. [14,15] In addition, the extremely basic reaction medium readily dissolves oxides and hydroxides, [16] which naturally are formed when adding the starting materials (e. g. RhI 3 ) to the massive amounts of hydroxide of the hydroflux. A rarely studied phenomenon of the hydroflux method is the concentration dependent product formation.…”