M[Y(BH4)4] and M2Li[Y(BH4)6−xClx] (M = Rb, Cs): new borohydride derivatives of yttrium and their hydrogen storage propertiesThis work is dedicated to Professor Lucjan Piela, our teacher and friend, at his 70th birthday.Electronic supplementary information (ESI) available: Rietveld refinement profiles, PXD scans, FTIR spectra, MS plots. CSD 425544 - Rb[Y(BH4)4], 425543 - Cs[Y(BH4)4], 425546 - Rb2Li[Y(BH4)6−xClx], 425545 - Cs2Li[Y(BH4)6−xClx]. For ESI see DOI: 10.1039/c3dt33048f
Two novel bimetallic borohydrides, Rb[Y(BH 4 ) 4 ] and Cs[Y(BH 4 ) 4 ], have been synthesised via mechanochemical reactions between MBH 4 , M = Rb or Cs and Y(BH 4 ) 3 . Both are ionic compounds comprising complex anions [Y(BH 4 ) 4 ] − and alkali metal cations, and they adopt crystal structures whi...
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| Main Authors | , , |
|---|---|
| Format | Journal Article |
| Language | English |
| Published |
23.04.2013
|
| Online Access | Get full text |
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| Summary: | Two novel bimetallic borohydrides, Rb[Y(BH
4
)
4
] and Cs[Y(BH
4
)
4
], have been synthesised
via
mechanochemical reactions between MBH
4
, M = Rb or Cs and Y(BH
4
)
3
. Both are ionic compounds comprising complex anions [Y(BH
4
)
4
]
−
and alkali metal cations, and they adopt crystal structures which were not observed previously for quasi-ternary borohydrides. LiCl, a by-product from the synthesis of Y(BH
4
)
3
, is not an unreactive dead-weight but rather it promotes formation of trimetallic borohydride-chlorides, M
2
Li[Y(BH
4
)
6−
x
Cl
x
], which crystallise in the elpasolite-type structures. Formation of Cs
2
Li[Y(BH
4
)
6−
x
Cl
x
] takes place during the mechanochemical synthesis of Cs[Y(BH
4
)
4
] at room temperature, while that of Rb
2
Li[Y(BH
4
)
6−
x
Cl
x
] only after heating of the sample above the melting point. The M[Y(BH
4
)
4
]/M
2
Li[Y(BH
4
)
6−
x
Cl
x
] mixtures slowly release H
2
when melted (
T
m
= 170 °C for M = Rb, 210 °C for M = Cs) but the main stage of thermal decomposition occurs at a
T
dec
of ∼270 °C, similarly to what is observed for K[Y(BH
4
)
4
] and NaBH
4
/Y(BH
4
)
3
composites. We also demonstrate how the
T
dec
of M[Y(BH
4
)
4
] salts may be tuned by choosing the MBH
4
precursor of the appropriate Lewis basicity.
Four novel derivatives of yttrium borohydride were synthesised and thermal stability of the whole series of these hydrogen-rich materials was discussed. |
|---|---|
| Bibliography: | Li[Y(BH 425545 - Cs ) Cl For ESI see DOI This work is dedicated to Professor Lucjan Piela, our teacher and friend, at his 70th birthday. 2 425546 - Rb 4 6 x 425543 - Cs[Y(BH Electronic supplementary information (ESI) available: Rietveld refinement profiles, PXD scans, FTIR spectra, MS plots. CSD 425544 - Rb[Y(BH 10.1039/c3dt33048f |
| ISSN: | 1477-9226 1477-9234 |
| DOI: | 10.1039/c3dt33048f |