Ammine Lanthanum and Cerium Borohydrides, M(BH4)3· nNH3; Trends in Synthesis, Structures, and Thermal Properties

Jakob B. Grinderslev; Morten B. Ley; Young Su Lee; Lars H. Jepsen; Mathias Jørgensen; Young Whan Cho; Jørgen Skibsted; Torben R. Jensen

doi:10.1021/acs.inorgchem.0c00817

Ammine Lanthanum and Cerium Borohydrides, M(BH₄)₃· nNH₃; Trends in Synthesis, Structures, and Thermal Properties

Jakob B. Grinderslev, Morten B. Ley, Young Su Lee, Lars H. Jepsen, Mathias Jørgensen, Young Whan Cho, Jørgen Skibsted, Torben R. Jensen^*

^*Corresponding author for this work

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Abstract

Ammine metal borohydrides show potential for solid-state hydrogen storage and can be tailored toward hydrogen release at low temperatures. Here, we report the synthesis and structural characterization of seven new ammine metal borohydrides, M(BH₄)₃·nNH₃, M = La (n = 6, 4, or 3) or Ce (n = 6, 5, 4, or 3). The two compounds with n = 6 are isostructural and have new orthorhombic structure types (space group P2₁2₁2) built from cationic complexes, [M(NH₃)₆(BH₄)₂]⁺, and are charge balanced by BH₄^-. The structure of Ce(BH₄)₃·5NH₃ is orthorhombic (space group C222₁) and is built from cationic complexes, [Ce(NH₃)₅(BH₄)₂]⁺, and charge balanced by BH₄^-. These are rare examples of borohydride complexes acting both as a ligand and as a counterion in the same compound. The structures of M(BH₄)₃·4NH₃ are monoclinic (space group C2), built from neutral molecular complexes of [M(NH₃)₄(BH₄)₃]. The new compositions, M(BH₄)₃·3NH₃ (M = La, Ce), among ammine metal borohydrides, are orthorhombic (space group Pna2₁), containing molecular complexes of [M(NH₃)₃(BH₄)₃]. A revised structural model for A(BH₄)₃·5NH₃ (A = Y, Gd, Dy) is presented, and the previously reported composition A(BH₄)₃·4NH₃ (A = Y, La, Gd, Dy) is proposed in fact to be M(BH₄)₃·3NH₃ along with a new structural model. The temperature-dependent structural properties and decomposition are investigated by in situ synchrotron radiation powder X-ray diffraction in vacuum and argon atmosphere and by thermal analysis combined with mass spectrometry. The compounds with n = 6, 5, and 4 mainly release ammonia at low temperatures, while hydrogen evolution occurs for M(BH₄)₃·3NH₃ (M = La, Ce). Gas-release temperatures and gas composition from these compounds depend on the physical conditions and on the relative stability of M(BH₄)₃·nNH₃ and M(BH₄)₃

Original language	English
Journal	Inorganic Chemistry
Volume	59
Issue	11
Pages (from-to)	7768-7778
ISSN	0020-1669
DOIs	https://doi.org/10.1021/acs.inorgchem.0c00817
Publication status	Published - Jun 2020

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10.1021/acs.inorgchem.0c00817

Ammine Lanthanum and Cerium Borohydrides, M(BH4)3·nNH3 Trends in Synthesis, Structures, and Thermal PropertiesAccepted manuscript, 1.45 MBLicence: Other

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@article{f133779010c249319d117da1802ac19b,

title = "Ammine Lanthanum and Cerium Borohydrides, M(BH4)3· nNH3; Trends in Synthesis, Structures, and Thermal Properties",

abstract = "Ammine metal borohydrides show potential for solid-state hydrogen storage and can be tailored toward hydrogen release at low temperatures. Here, we report the synthesis and structural characterization of seven new ammine metal borohydrides, M(BH4)3·nNH3, M = La (n = 6, 4, or 3) or Ce (n = 6, 5, 4, or 3). The two compounds with n = 6 are isostructural and have new orthorhombic structure types (space group P21212) built from cationic complexes, [M(NH3)6(BH4)2]+, and are charge balanced by BH4-. The structure of Ce(BH4)3·5NH3 is orthorhombic (space group C2221) and is built from cationic complexes, [Ce(NH3)5(BH4)2]+, and charge balanced by BH4-. These are rare examples of borohydride complexes acting both as a ligand and as a counterion in the same compound. The structures of M(BH4)3·4NH3 are monoclinic (space group C2), built from neutral molecular complexes of [M(NH3)4(BH4)3]. The new compositions, M(BH4)3·3NH3 (M = La, Ce), among ammine metal borohydrides, are orthorhombic (space group Pna21), containing molecular complexes of [M(NH3)3(BH4)3]. A revised structural model for A(BH4)3·5NH3 (A = Y, Gd, Dy) is presented, and the previously reported composition A(BH4)3·4NH3 (A = Y, La, Gd, Dy) is proposed in fact to be M(BH4)3·3NH3 along with a new structural model. The temperature-dependent structural properties and decomposition are investigated by in situ synchrotron radiation powder X-ray diffraction in vacuum and argon atmosphere and by thermal analysis combined with mass spectrometry. The compounds with n = 6, 5, and 4 mainly release ammonia at low temperatures, while hydrogen evolution occurs for M(BH4)3·3NH3 (M = La, Ce). Gas-release temperatures and gas composition from these compounds depend on the physical conditions and on the relative stability of M(BH4)3·nNH3 and M(BH4)3",

author = "Grinderslev, {Jakob B.} and Ley, {Morten B.} and Lee, {Young Su} and Jepsen, {Lars H.} and Mathias J{\o}rgensen and Cho, {Young Whan} and J{\o}rgen Skibsted and Jensen, {Torben R.}",

year = "2020",

month = jun,

doi = "10.1021/acs.inorgchem.0c00817",

language = "English",

volume = "59",

pages = "7768--7778",

journal = "Inorganic Chemistry",

issn = "0020-1669",

publisher = "AMER CHEMICAL SOC",

number = "11",

}

Ammine Lanthanum and Cerium Borohydrides, M(BH₄)₃· nNH₃; Trends in Synthesis, Structures, and Thermal Properties. / Grinderslev, Jakob B.; Ley, Morten B.; Lee, Young Su et al.
In: Inorganic Chemistry, Vol. 59, No. 11, 06.2020, p. 7768-7778.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

TY - JOUR

T1 - Ammine Lanthanum and Cerium Borohydrides, M(BH4)3· nNH3; Trends in Synthesis, Structures, and Thermal Properties

AU - Grinderslev, Jakob B.

AU - Ley, Morten B.

AU - Lee, Young Su

AU - Jepsen, Lars H.

AU - Jørgensen, Mathias

AU - Cho, Young Whan

AU - Skibsted, Jørgen

AU - Jensen, Torben R.

PY - 2020/6

Y1 - 2020/6

N2 - Ammine metal borohydrides show potential for solid-state hydrogen storage and can be tailored toward hydrogen release at low temperatures. Here, we report the synthesis and structural characterization of seven new ammine metal borohydrides, M(BH4)3·nNH3, M = La (n = 6, 4, or 3) or Ce (n = 6, 5, 4, or 3). The two compounds with n = 6 are isostructural and have new orthorhombic structure types (space group P21212) built from cationic complexes, [M(NH3)6(BH4)2]+, and are charge balanced by BH4-. The structure of Ce(BH4)3·5NH3 is orthorhombic (space group C2221) and is built from cationic complexes, [Ce(NH3)5(BH4)2]+, and charge balanced by BH4-. These are rare examples of borohydride complexes acting both as a ligand and as a counterion in the same compound. The structures of M(BH4)3·4NH3 are monoclinic (space group C2), built from neutral molecular complexes of [M(NH3)4(BH4)3]. The new compositions, M(BH4)3·3NH3 (M = La, Ce), among ammine metal borohydrides, are orthorhombic (space group Pna21), containing molecular complexes of [M(NH3)3(BH4)3]. A revised structural model for A(BH4)3·5NH3 (A = Y, Gd, Dy) is presented, and the previously reported composition A(BH4)3·4NH3 (A = Y, La, Gd, Dy) is proposed in fact to be M(BH4)3·3NH3 along with a new structural model. The temperature-dependent structural properties and decomposition are investigated by in situ synchrotron radiation powder X-ray diffraction in vacuum and argon atmosphere and by thermal analysis combined with mass spectrometry. The compounds with n = 6, 5, and 4 mainly release ammonia at low temperatures, while hydrogen evolution occurs for M(BH4)3·3NH3 (M = La, Ce). Gas-release temperatures and gas composition from these compounds depend on the physical conditions and on the relative stability of M(BH4)3·nNH3 and M(BH4)3

AB - Ammine metal borohydrides show potential for solid-state hydrogen storage and can be tailored toward hydrogen release at low temperatures. Here, we report the synthesis and structural characterization of seven new ammine metal borohydrides, M(BH4)3·nNH3, M = La (n = 6, 4, or 3) or Ce (n = 6, 5, 4, or 3). The two compounds with n = 6 are isostructural and have new orthorhombic structure types (space group P21212) built from cationic complexes, [M(NH3)6(BH4)2]+, and are charge balanced by BH4-. The structure of Ce(BH4)3·5NH3 is orthorhombic (space group C2221) and is built from cationic complexes, [Ce(NH3)5(BH4)2]+, and charge balanced by BH4-. These are rare examples of borohydride complexes acting both as a ligand and as a counterion in the same compound. The structures of M(BH4)3·4NH3 are monoclinic (space group C2), built from neutral molecular complexes of [M(NH3)4(BH4)3]. The new compositions, M(BH4)3·3NH3 (M = La, Ce), among ammine metal borohydrides, are orthorhombic (space group Pna21), containing molecular complexes of [M(NH3)3(BH4)3]. A revised structural model for A(BH4)3·5NH3 (A = Y, Gd, Dy) is presented, and the previously reported composition A(BH4)3·4NH3 (A = Y, La, Gd, Dy) is proposed in fact to be M(BH4)3·3NH3 along with a new structural model. The temperature-dependent structural properties and decomposition are investigated by in situ synchrotron radiation powder X-ray diffraction in vacuum and argon atmosphere and by thermal analysis combined with mass spectrometry. The compounds with n = 6, 5, and 4 mainly release ammonia at low temperatures, while hydrogen evolution occurs for M(BH4)3·3NH3 (M = La, Ce). Gas-release temperatures and gas composition from these compounds depend on the physical conditions and on the relative stability of M(BH4)3·nNH3 and M(BH4)3

UR - http://www.scopus.com/inward/record.url?scp=85085657218&partnerID=8YFLogxK

U2 - 10.1021/acs.inorgchem.0c00817

DO - 10.1021/acs.inorgchem.0c00817

M3 - Journal article

C2 - 32395988

AN - SCOPUS:85085657218

SN - 0020-1669

VL - 59

SP - 7768

EP - 7778

JO - Inorganic Chemistry

JF - Inorganic Chemistry

IS - 11

ER -

Ammine Lanthanum and Cerium Borohydrides, M(BH₄)₃· nNH₃; Trends in Synthesis, Structures, and Thermal Properties

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