Potassium nonahydridorhenate

Potassium nonahydridorhenate
Properties
Molecular formula	K2ReH9
Molar mass	273.473 g/mol
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Infobox references

Potassium nonahydridorhenate is an inorganic compound with the formula K₂ReH₉. This colourless salt features the ReH₉²⁻ anion, a rare example of a coordination complex bearing only hydride ligands.

The study of rhenium hydrides can be traced to the 1950s and included reports of the "rhenide" anion, supposedly Re⁻. These reports led to a series of investigations by A. P. Ginsberg and coworkers on the products from the reduction of perrhenate.^[1]

Structure, synthesis, and properties

ReH₉²⁻ is an unusual example of a nine-coordinated complex, the high coordination number being attributed to the small size of the hydride ligand and the high positive charge on the Re(VII) center. The structure consists of a tricapped trigonal prism.^[2] The diamagnetic sodium salt, like the analogous technetium compound, is prepared by treating an ethanol solution of sodium perrhenate, NaReO₄, with sodium metal.^[3] Via cation exchange, it can be converted to the corresponding tetraethylammonium salt, (NEt₄)₂ReH₉.

References

1. ^ A. P. Ginsberg, J. M. Miller, J. R. Cavanaugh, and B. P. Dailey (1960). "Evidence for the Existence of a Potassium Rhenium Hydride and its Bearing on the Nature of the (-1)-Oxidation State of Rhenium". Nature 185 (4712): 528–9. doi:10.1038/185528a0. 
2. ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
3. ^ A. P. Ginsberg, C. R. Sprinkle (1972). "Nonahydridorhenate Salts". Inorganic Syntheses. Inorganic Syntheses 13: 219–225. doi:10.1002/9780470132449.ch45. ISBN 9780470132449.