Plumbane
Chemical compound
From Wikipedia, the free encyclopedia
Plumbane is an inorganic chemical compound with the chemical formula PbH4. It is a colorless gas. It is a metal hydride and group 14 hydride composed of lead and hydrogen.[1] Plumbane is not well characterized or well known, and it is thermodynamically unstable with respect to the loss of a hydrogen atom.[2] Derivatives of plumbane include lead tetrachloride, PbCl4, and tetraethyllead, (CH3CH2)4Pb.
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 Lead, Pb Hydrogen, H | |
| Names | |
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| IUPAC name
Plumbane | |
| Other names
lead tetrahydride, tetrahydridolead, lead(IV) hydride, hydrogen plumbide | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChemSpider | |
PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| PbH4 | |
| Molar mass | 211.23 g/mol |
| Appearance | Colorless gas |
| Boiling point | −13 °C (9 °F; 260 K) |
| Structure | |
| Tetrahedral at the Pb atom | |
| Related compounds | |
Related tetrahydride compounds |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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History
Until recently, it was uncertain whether plumbane had ever actually been synthesized,[3] although the first reports date back to the 1920s[4] and in 1963, Saalfeld and Svec reported the observation of PbH+
4 by mass spectrometry.[5] Plumbane has repeatedly been the subject of Dirac–Hartree–Fock relativistic calculation studies, which investigate the stabilities, geometries, and relative energies of hydrides of the formula MH4 or MH2.[2][6][7]
Properties
Plumbane is an unstable colorless gas and is the heaviest group IV hydride;[8] and has a tetrahedral (Td) structure with an equilibrium distance between lead and hydrogen of 1.73 Å.[9] By weight, plumbane is 1.91% hydrogen and 98.09% lead. In plumbane, the formal oxidation states of hydrogen and lead are +1 and −4, respectively, because the electronegativity of lead(IV) is higher than that of hydrogen. The stability of hydrides MH4 (M = C–Pb) decreases as the atomic number of M increases.
Preparation
Early studies of PbH4 revealed that the molecule is unstable as compared to its lighter congeners silane, germane, and stannane.[10] It cannot be made by methods used to synthesize GeH4 or SnH4.
In 1999, plumbane was synthesized from lead(II) nitrate, Pb(NO3)2, and sodium borohydride, NaBH4.[11] A non-nascent mechanism for plumbane synthesis was reported in 2005.[12]
In 2003, Wang and Andrews carefully studied the preparation of PbH4 by laser ablation and additionally identified the infrared (IR) bands.[13]