Ruthenium(V) Oxides from Low‐Temperature Hydrothermal Synthesis

Abstract

hydrothermal synthesis of the ruthenium oxides Ca 1.5 Ru 2 O 7 , SrRu 2 O 6 , and Ba 2 Ru 3 O 9 (OH) is reported. Ca 1.5 Ru 2 O 7 is a defective pyrochlore containing Ru V/VI ; SrRu 2 O 6 is a layered Ru V oxide with a PbSb 2 O 6 structure, whilst Ba 2 Ru 3 O 9 (OH) has a previously unreported structure type with orthorhombic symmetry solved from synchrotron X-ray and neutron powder diffraction. SrRu 2 O 6 exhibits unusually high-temperature magnetic order, with antiferromagnetism persisting to at least 500 K, and refinement using room temperature neutron powder diffraction data provides the magnetic structure. All three ruthenates are metastable and readily collapse to mixtures of other oxides upon heating in air at temperatures around 300-500 8C, suggesting they would be difficult, if not impossible, to isolate under conventional high-temperature solid-state synthesis conditions.

AgRuO3, a Strongly Exchange‐Coupled Honeycomb Compound Lacking Long‐Range Magnetic Order

“…Examples knowna mong ternary oxides are Ag 5 Pb 2 O 6 [41] and SrRu 2 O 6 , [28,32,33] or,m ore frequently encountered, alkali oxo-metalates of general com-positionA 2 MO 3 ,w ith A = Li, Na and M = tetravalent metal, where the voids of the honeycomb layers are occupied by an alkali metal ion. Its organization can be addressed essentially as as tackingo fh oneycomb-type (RuO 3 ) À polyoxonanions along the c axis with the silver atoms located within the van der Waals gaps (Figure1).…”

“…Such as tructural buildingp rinciple is rather common. Examples knowna mong ternary oxides are Ag 5 Pb 2 O 6 [41] and SrRu 2 O 6 , [28,32,33] or,m ore frequently encountered, alkali oxo-metalates of general com-positionA 2 MO 3 ,w ith A = Li, Na and M = tetravalent metal, where the voids of the honeycomb layers are occupied by an alkali metal ion. [13][14][15][16][17][18][19][20][21][22] Compared to the standard representatives mentioned, the crystal structure of AgRuO 3 is singular and displays distinctly differentf eatures in relevant respects.…”

“…[14] Li 2 IrO 3 ,o nt he other extreme, displays an unusuale lectronic ground state with anisotropic spin interactions causing ad istinctly new kind of magnetic frustration. [28] This new ternary oxide belongs to the family of layered oxides AB 2 O 6 ,a doptingt he PbSb 2 O 6 structure type. [28] This new ternary oxide belongs to the family of layered oxides AB 2 O 6 ,a doptingt he PbSb 2 O 6 structure type.…”

“…[23][24][25][26][27] Recently,t he synthesis and characterization of SrRu 2 O 6 was reported. [28] This new ternary oxide belongs to the family of layered oxides AB 2 O 6 ,a doptingt he PbSb 2 O 6 structure type. Family members hosting an open shell TM at the As ite have been reported before as MAs 2 O 6 ,M= Mn, Co, Ni, and Pd, [29][30][31] where PdAs 2 O 6 exhibits an appreciably high antiferromagnetic ordering temperature (T N )o f1 40 K. [30,31] SrRu 2 O 6 represents the first realization of this motif with an open shell TM located at the Bs ite;t hus developing a2 Dh oneycomb polyoxoanion.…”

Spin waves and spin-state transitions in a ruthenate high-temperature antiferromagnet

“…Here we introduce a resonant inelastic x-ray scattering (RIXS) [10,11] technique capable of probing collective modes in microcrystals of 4d-electron materials. We present a comprehensive set of data on spin waves and spin-state transitions in the honeycomb antiferromagnet SrRu 2 O 6 [12], which possesses an unusually high Néel temperature [13][14][15][16][17][18]. The new RIXS method provides fresh insight into the unconventional magnetism of SrRu 2 O 6 , and enables momentum-resolved spectroscopy of a large class of 4d transition-metal compounds.…”