Borides of Rhenium and the Platinum Metals. The Crystal Structure of Re7B3, ReB3, Rh7B3, RhB~1.1, IrB~1.1 and PtB.

Aronsson, B.; Stenberg, E.; Åselius, J.; Refn, Susanne; Westin, Gertrud

doi:10.3891/acta.chem.scand.14-0733

Cited by 89 publications

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“…), this mode of combination of prisms The binary transition metal and platinum metal borides T 7 B 3 (T = Re, Ru, Rh) are also representatives of this structural type. 28 Thus, in the crystal structure of the ternary compound Sc 4 Rh 17 B 12 , one can distinguish a frag ment of the binary boride Rh 7 B 3 structure (see Fig. 3, c).…”

Section: Resultsmentioning

confidence: 99%

New scandium rhodium boride Sc4Rh17B12 with a framework structure: synthesis, crystal structure, and properties

et al. 2008

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The new scandium rhodium boride Sc 4 Rh 17 B 12 was synthesized by arc melting of the elements followed by annealing in inert atmosphere. The crystal structure of Sc 4 Rh 17 B 12 was solved using single crystal X ray diffraction data. The structure can be described as a three dimensional frame work formed by trigonal prisms [BRh 6 ] and [BRh 5 Sc] with isolated boron atoms inside the prisms and trigonal prisms [BRh 5 B] representing the coordination polyhedra of paired boron atoms. The temperature dependences of the magnetic susceptibility and specific resistance of Sc 4 Rh 17 B 12 revealed that the compound is a Pauli paramagnet and shows metal like specific resistance.Key words: Sc 4 Rh 17 B 12 , synthesis, crystal structure.Owing to the specific electronic structure, scandium is often assigned to rare earth elements. However, due to the small atomic radius of Sc (r Sc = 1.606 Å) 1 close to the ra dii of alkaline earth metals (for example, r Mg = 1.600 Å), 1 the crystal chemistry of scandium compounds is unique in many respects. Thus ternary scandium and platinum metal borides tend to exist as both structural analogs of rare earth element borides or compounds isostructural to complex magnesium borides and as unique structural types, which are often related to transition metal com pounds.At low boron content (M/B > 4, where M is the total quantity of metals in the compound, M = Sc + T) in Sc-T-B systems, where T = Ru, Rh, Re, Os, Ir, perovs kite like compounds ScT 3 B 1-x , 2-4 typical of lanthanide containing systems, are formed. These compounds can be considered as interstitial solid solutions containing boron in the octahedral cavities of ScT 3 intermetallics. As the boron content increases to the ratio 1 ≤ M/B ≤ 4, phases with structures identical to the structures of the corresponding magnesium borides are formed (ScOs . 7)). Also, among the ternary scandi um and platinum metal borides in the composition re gion of 1 ≤ M/B ≤ 2, there are compounds that form their own types of structure. These structures are often derived from ternary rare earth element borides and are formed as a result of change in the composition or distor tions associated with the small atomic radius of scan dium (ScIr 3 B 4 , 9 ScOsB 2 , 10 ScIr 3 B 2 , 11 Sc 2 (Os,Ru) 5 B 4 (see Ref. 12)). In the boron rich region, there exist phas es Sc 2 TB 6 5,13-14 crystallizing in the Y 2 ReB 6 structural type, 15 which is frequently encountered among rare earth element borides.Considerable researchers´ interest has always been at tracted by compounds of the ET 4 B 4 class (E is a rare earth metal) in the Sc-T-B systems with 1 ≤ M/B < 2.

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Section: Resultsmentioning

confidence: 99%

New scandium rhodium boride Sc4Rh17B12 with a framework structure: synthesis, crystal structure, and properties

et al. 2008

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“…However, in case of a full occupation of the B3 site, infinite B-B chains would form at a rather short distance (d B3-B3 = 0.1610 nm) Although our X-ray powder pattern of a single-phase alloy (nominal composition Ir 52 B 48 in at.%) annealed at 900°C could be indexed on the basis of the α-ThSi 2 structure type (see Fig. 3) as published for the compound labelled in the literature as 'IrB 1.1 ' (space group I4 1 /amd; a = 0.281 and c = 1.026 nm [12]), the calculated intensities from Rietveld refinement did not fit well with the experimental observation. Therefore, a structure analysis has been attempted on a single crystal specimen mechanically isolated from the sample with nominal composition Ir 53 B 47 (in at.%) obtained after the DSC measurement.…”

Section: Articlesmentioning

confidence: 99%

“…It should be noted here that the intensities of the superstructure reflections are rather small and almost indistinguishable from the background. In order to rule out the existence of a disordered and defect α-ThSi 2 structure type (as reported earlier [8,12]) in the phase diagram, further single crystals were investigated, which were isolated from two alloys, one located close to the B-poor and the second one located close to the B-rich flanks of the Ir 5 B 4 phase, respectively. The locations of these alloys were carefully checked by DTA yielding small signals of the relevant isothermal reactions of the adjoining phases.…”

Section: Articlesmentioning

confidence: 99%

“…X-ray powder and single crystal (Weissenberg) photographs served to evaluate the crystal structure of IrB 1.1 , which was reported to be isotypic with the α-ThSi 2 structure type (space group I4 1 /amd; a = 0.2810, c =1.0263 nm) exhibiting a severe defect at the boron sites (8e sites randomly occupied by ~50% of B atoms) [12]. For the compound richest in boron, 'IrB 2 ' , monoclinic symmetry (space group C2/m) was established from X-ray single crystal multi-film Weissenberg photographs yielding a crystal structure described as a stacking of puckered boron layers (A) and puckered double layers of metal atoms (B) in the simple sequence ABAB in c-direc-…”

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Crystal structures and constitution of the binary system iridium-boron

et al. 2015

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GPa [2] (48 GPa (0.5 N) [3]) or 26.6 GPa (39.3 GPa (0.5 N)) [2] with rather different hardness values due to the anisotropic crystal structure (for details on the crystal structure of W 1−x B 3 , see [4]). Vicker's hardness measurements on the boron richest iridium boride IrB 1.35 revealed a load independent value of 18.2 GPa (at 9.81 N) but 49.8 GPa at 0.49 N [5] and at such low loads the hardness is therefore comparable with bulk samples of ReB 2 . Quite high hardness values were also recorded for IrB 1.1 thin films (on SiO 2 substrate) revealing an intrinsic film hardness of 43(±5) GPa [6].Investigations on the constitution of the binary system Ir-B revealed the existence of three compounds Ir 3 B 2 , IrB and IrB 2 [7−9]. Some of the early reports were mainly concerned with the metal-rich eutectic (1046°C at 21.4 at.% B [10]), with the optimization of synthesis techniques [8] and with the stability of IrB 1.1 against various acids and bases [11]. Melting point (T m = 1190 ± 20°C), microhardness 1652 ± 80 kgf/mm 2 , Seebeck coefficient (20−800°C, S V , min = −9 μV/K at 350°C) and electrical resistance (20−800°C) for IrB 1.1 were reported by Samsonov et al. [8]. X-ray powder and single crystal (Weissenberg) photographs served to evaluate the crystal structure of IrB 1.1 , which was reported to be isotypic with the α-ThSi 2 structure type (space group I4 1 /amd; a = 0.2810, c =1.0263 nm) exhibiting a severe defect at the boron sites (8e sites randomly occupied by ~50% of B atoms) [12]. For the compound richest in boron, 'IrB 2 ' , monoclinic symmetry (space group C2/m) was established from X-ray single crystal multi-film Weissenberg photographs yielding a crystal structure described as a stacking of puckered boron layers (A) and puckered double layers of metal atoms (B) in the simple sequence ABAB in c-direc-

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“…Several synthesis methods have been employed to obtain ReB 2 as powder, single crystals or as thin films, including solid state reactions, self-propagating high-temperature synthesis, arc melting, zone melting, floating zone furnace-based techniques and pulsed laser deposition, among others [2,16e19]. In contrast, the other two binary phases that have been observed in the ReeB system, namely Re 3 B and Re 7 B 3 have attracted much less attention [20,21]. Kawano et al [22] reported the superconductivity of Re 7 B 3 (T c ¼ 3.3 K) and Re 3 B (T c ¼ 4.8 K), while Takagiwa et al [23] reported the magnetic properties of Re 3 B.…”

Section: Q1mentioning

confidence: 99%

In situ study of the formation of rhenium borides from the elements at high-(p, T) conditions: Extreme incompressibility of Re7B3 and formation of new phases

Juarez‐Arellano

Winkler

Friedrich

et al. 2013

Solid State Sciences

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Borides of Rhenium and the Platinum Metals. The Crystal Structure of Re7B3, ReB3, Rh7B3, RhB~1.1, IrB~1.1 and PtB.

Cited by 89 publications

References 0 publications

New scandium rhodium boride Sc4Rh17B12 with a framework structure: synthesis, crystal structure, and properties

New scandium rhodium boride Sc4Rh17B12 with a framework structure: synthesis, crystal structure, and properties

Crystal structures and constitution of the binary system iridium-boron

In situ study of the formation of rhenium borides from the elements at high-(p, T) conditions: Extreme incompressibility of Re7B3 and formation of new phases

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