Polymorphism and hydrogen discharge from holmium borohydride, Ho(BH4)3, and KHo(BH4)4

Wegner, Wojciech; Jaroń, Tomasz; Grochala, Wojciech

doi:10.1016/j.ijhydene.2014.10.013

Cited by 24 publications

(21 citation statements)

References 49 publications

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“…23.3 Hz), while milling bowl was slightly cooled between the periods, using liquid nitrogen to avoid thermal decomposition and overheating of the products. Two polymorphic forms of Ln(BH 4 ) 3 were prepared that both exhibit a ReO 3 ‐type 3D network with BH 4 – anions coordinating Ln III cations in bidentate fashion and bridging Ln III cations in all three directions.

{normalLnCl}_{3} + 3 {normalLiBH}_{4} \to α -Ln {({normalBH}_{4})}_{3} + 3 LiCl

{normalLnCl}_{3} + 12 {normalLiBH}_{4} \to β -Ln {({normalBH}_{4})}_{3} + 3 LiCl + 9 {normalLiBH}_{4}

{normalLnCl}_{3} + 3 {normalLiBH}_{4} + {normalMBH}_{4} \to MLn {({normalBH}_{4})}_{4} + 3 LiCl

{normalYbCl}_{3} + 12 {normalLiBH}_{4} \to LiYb {({normalBH}_{4})}_{4} + 3 LiCl + 8 {normalLiBH}_{4}

…”

Section: Methodsmentioning

confidence: 99%

Borohydride as Magnetic Superexchange Pathway in Late Lanthanide Borohydrides

et al. 2019

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The magnetic characteristics of a series of borohydride‐based systems, including binary α‐/β‐Ln(BH4)3 phases (Ln = Gd, Tb, Dy, Ho, Er, and Tm) with direct Ln–HBH–Ln bridges and selected mixed‐metal systems, LiYb(BH4)4, NaYb(BH4)4, KHo(BH4)4, RbTm(BH4)4, with isolated Ln3+ ions embedded in [Ln(BH4)4]– anions are described for the first time using SQUID magnetometry and DFT+U calculations. Crystal field effects as well as the nature and strength of magnetic superexchange interactions via BH4– ligands are established based on a ligand field theory approach. We find Auzel's scalar crystal field strength parameter (Nv, the weighted quadratic mean of the ligand field parameters Bkq) for these systems to be substantial, in particular for α‐Ho(BH4)3, indicating a significant covalent component in the Ho···H bonding. The BH4– anion is capable of mediating both weakly ferro‐ or antiferromagnetic superexchange. Quantum mechanical DFT+U calculations, even when including spin‐orbit coupling effects, do not reliably describe the sign and the size of the magnetic superexchange constants in these systems.

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{normalLnCl}_{3} + 3 {normalLiBH}_{4} \to α -Ln {({normalBH}_{4})}_{3} + 3 LiCl

{normalLnCl}_{3} + 12 {normalLiBH}_{4} \to β -Ln {({normalBH}_{4})}_{3} + 3 LiCl + 9 {normalLiBH}_{4}

{normalLnCl}_{3} + 3 {normalLiBH}_{4} + {normalMBH}_{4} \to MLn {({normalBH}_{4})}_{4} + 3 LiCl

{normalYbCl}_{3} + 12 {normalLiBH}_{4} \to LiYb {({normalBH}_{4})}_{4} + 3 LiCl + 8 {normalLiBH}_{4}

…”

Section: Methodsmentioning

confidence: 99%

Borohydride as Magnetic Superexchange Pathway in Late Lanthanide Borohydrides

et al. 2019

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“…Ultimately the decomposition reaction results in the formation of the corresponding rare earth hydrides and borides which is favored over the formation of elemental boron for technological applications. Crystalline decomposition products are not always formed, however, even when heating the materials to 400-500 • C, as is the case for Pr(BH 4 ) 3 and Ho(BH 4 ) 3 [30,32]. The thermal decomposition of the LiRE(BH 4 ) 3 Cl-type compounds appears to be more complex and proceeds via a multi-step process involving at least two different steps over a temperature range of up to 50 • C. The highest decomposition temperature of 266 • C is observed for LiLa(BH 4 ) 3 Cl while LiNd(BH 4 ) 3 Cl possesses the lowest one with 241 • C. The variation in decomposition temperature is far less pronounced in the rare earth borohydrides as compared to alkali or alkaline earth borohydrides though.…”

Section: Yttrium Borohydridementioning

confidence: 98%

“…The Na(BH4)6 octahedra form edge-sharing chains along the c-axis, with the chains also being interconnected by egde-sharing Sc(BH4)4 tetrahedra. NaY(BH4)4 [10,40], NaEr(BH4)4 [42], KHo(BH4)4 [32], o-KY(BH4)4 [43], KEr(BH4)4 [44], and KYb(BH4)4 [45] are isostructural to NaSc(BH4)4. KSc(BH4)4 (space group Pnma) contains similar tetrahedral [Sc(BH4)4] − complexes while the coordination number of alkali metal increases further to eight [46].…”

Section: Bi-and Trimetallic Re-borohydridesmentioning

confidence: 99%

“…However, the deuterated PND sample contained highly neutron-absorbing natural boron and they were thus unable to refine the atomic positions of boron or deuterium. [19,29,30,32,33]. Due to the challenges with extreme neutron absorption in Sm, Dy and Gd, in addition to the general problem with absorption in natural boron and incoherent scattering from H, these phases have not been investigated by PND and thus accurate positions for B and H have not been obtained.…”

Section: Monometallic Re-borohydridesmentioning

confidence: 99%

“…The correlation between the unit cell parameters and the cation radii are shown in Figure 2. SR-PXD measurements have revealed that β-RE(BH 4 ) 3 modifications also exist for Ce(BH 4 ) 3 , Pr(BH 4 ) 3 , Sm(BH 4 ) 3 , Ho(BH 4 ) 3 , Er(BH 4 ) 3 and Yb(BH 4 ) 3 [19,29,30,32,34]. Due to the chemical similarity of these RE ions and Y 3+ , it seems likely that these phases take structures with ordered BH 4 − orientations.…”

Section: Monometallic Re-borohydridesmentioning

confidence: 99%

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Rare Earth Borohydrides—Crystal Structures and Thermal Properties

et al. 2017

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Rare earth (RE) borohydrides have received considerable attention during the past ten years as possible hydrogen storage materials due to their relatively high gravimetric hydrogen density. This review illustrates the rich chemistry, structural diversity and thermal properties of borohydrides containing RE elements. In addition, it highlights the decomposition and rehydrogenation properties of composites containing RE-borohydrides, light-weight metal borohydrides such as LiBH 4 and additives such as LiH.

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Inclusion of Neon into an Yttrium Borohydride Structure at Elevated Pressure – An Experimental and Theoretical Study

et al. 2020

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We report here the experimental and computational results of a high‐pressure study (up to 40 GPa) of yttrium borohydride. During compression in neon pressure medium the cage‐like RuO3 structure of α‐Y(BH4)3 is stabilized by the formation of the inclusion compound with this chemically inert gas. Ne atoms fill the voids available in the crystal structure of the host at the special 0 0 0 and 0.5 0.5 0.5 positions. The inclusion compound preserves high crystallinity up to ca. 10 GPa, while gradual amorphization is observed at higher pressures. The results of our DFT calculations indicate that although the molecular volumes of the tested system are rather well modeled using PBEsol functional, significant improvement, especially in terms of the phases' relative energy can be made when applying dispersion correction, using PBE‐TS approach.

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Polymorphism and hydrogen discharge from holmium borohydride, Ho(BH4)3, and KHo(BH4)4

Cited by 24 publications

References 49 publications

Borohydride as Magnetic Superexchange Pathway in Late Lanthanide Borohydrides

Borohydride as Magnetic Superexchange Pathway in Late Lanthanide Borohydrides

Rare Earth Borohydrides—Crystal Structures and Thermal Properties

Inclusion of Neon into an Yttrium Borohydride Structure at Elevated Pressure – An Experimental and Theoretical Study

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