Actinium hydride

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Actinium hydride
Other names Actinium dihydride
Identifiers
Standard InChI InChI=1S/Ac.2H/q+2;2*-1
Standard InChIKey KJTMAIPZQHGTQQ-UHFFFAOYSA-N
CAS number [60936-81-4]
Properties[1]
Chemical formula AcH2
Molar mass 229.04 g mol−1 [note 1]
Density 8.35 g cm−3
Structure[1]
Lattice constant a = 567.0(6) pm
Related compounds
Other cations Scandium hydride
Yttrium hydride
Lanthanum hydride
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Actinium hydride, AcH2, is a purported binary compound of hydrogen and actinium. It was prepared as a second cubic phase during the preparation of actinium metal by the reduction of actinium chloride with potassium vapour at 350 °C: the origin of the hydrogen was not explained.[1] Nevertheless, the compound was claimed on the basis of its isostructurality with known lanthanum hydride LaH2, which was formed in a parallel experiment.[1]

The dihydrides of the group 3 metals do not contain M2+ ions: instead, the bonding can be described as M3+ 2 H e, with the additional electron required for electroneutrality being in a delocalized conduction band.[5][6]

Notes and references

Notes

  1. The molar mass is based on actinium-227 (t½ = 21.772(3) a; Ar = 227.027 7521(26)),[2] the most commonly encountered isotope of actinium and the one used in the original studies.[3][4]

References

  1. 1.0 1.1 1.2 1.3 Kirby, H. W.; Morss, L. R. Actinium. In The Chemistry of the Actinide and Transactinide Elements, 3rd ed.; Morss, Lester R.; Edelstein, Norman M.; Fuger, Jean, Eds.; Springer: Dordrecht, the Netherlands, 2006; Vol. 1, Chapter 2, pp 18–51. doi:10.1007/1-4020-3598-5_2, <http://radchem.nevada.edu/classes/rdch710/files/actinium.pdf>.
  2. Audi, G.; Bersillon, O.; Blachot, J.; Wapstra, A. H. The NUBASE evaluation of nuclear and decay properties. Nucl. Phys. A 2003, 729, 3–128. doi:10.1016/j.nuclphysa.2003.11.001, <http://amdc.in2p3.fr/nubase/Nubase2003.pdf>.
  3. Farr, J. D.; Giorgi, A. L.; Money, R. K.; Bowman, M. G. The Crystal Structure of Actinium Metal and Actinium Hydride; Los Alamos National Laboratory: Los Alamos, N.Mex, 1953. Report LA-1545.
  4. Farr, J. D.; Giorgi, A. L.; Bowman, M. G.; Money, R. K. The crystal structure of actinium metal and actinium hydride. J. Inorg. Nucl. Chem. 1961, 18, 42–47. DOI: 10.1016/0022-1902(61)80369-2.
  5. Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; p 1107. ISBN 0-08-022057-6.
  6. Bos, William G. Bonding in Group IIIb hydrides. Empirical approach. Acc. Chem. Res. 1972, 5 (10), 342–47. DOI: 10.1021/ar50058a004.

External links

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