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User:Praseodymium-141/Protactinocene

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Praseodymium-141/Protactinocene
Names
IUPAC name
Bis(η8-cyclooctatetraenyl)protactinium(IV)
Other names
Protactinium cyclooctatetraenide
Pa(COT)2
Identifiers
3D model (JSmol)
  • InChI=1S/2C5H5.Pa/c2*1-2-4-5-3-1;/h2*1-5H;/q2*-1;+2
  • [Pa].C1=CC=CC=CC=C1.C1=CC=CC=CC=C1
Properties
C16H16Pa
Molar mass 439.340 g·mol−1
Appearance yellow-ish crystals
insoluble, does not react with water
Solubility in chlorocarbons sparingly soluble (ca. 0.5 g/L)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
radiation hazard, pyrophoric
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Tracking categories (test):

Protactinocene, Pa(C8H8)2, is an organoprotactinium compound composed of a protactinium atom sandwiched between two cyclooctatetraenide (COT2-) rings. As a solid it has a yellowish colour.[1]

It was one of the first organoprotactinium compounds to be synthesised, and is a member of the actinocene family of actinide-based metallocenes.[1] It was synthesized in 1974.[2]

Structure

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Protactinocene assumes a monoclinic crystal structure (P21/n space group) which is isomorphous to uranocene and thorocene.[3]

Bonding

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The protactinium-cyclooctatetraenyl bonding, like other actinide bonds, has been of interest for multiple theoretical studies.[4] Computational chemistry methods indicate bonding with a large covalent character resulting mainly from the mixing of protactinium 6d orbitals with ligand π-orbitals, with a smaller interaction involving the protctinium 5f and ligand π-orbitals.[4] The covalent component is characterised by donation of electron density to the protactinium.

References

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  1. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 1278–1280. ISBN 9780750633659.
  2. ^ Goffart, J.; Fuger, J.; Brown, D.; Duyckaerts, G. (1974-05-01). "On the cyclooctatetraenyl compounds of actinide elements part II. Bis-(cyclooctatetraenyl) protactinium(IV)". Inorganic and Nuclear Chemistry Letters. 10 (5): 413–419. doi:10.1016/0020-1650(74)80119-4. ISSN 0020-1650.
  3. ^ Ridder, D. J. A. De; Rebizant, J.; Apostolidis, C.; Kanellakopulos, B.; Dornberger, E. (1996). "Bis(cyclooctatetraenyl)neptunium(IV)". Acta Crystallographica Section C. 52 (3): 597–600. doi:10.1107/S0108270195013047. ISSN 1600-5759.
  4. ^ a b Kerridge, Andrew (2014). "f-Orbital covalency in the actinocenes (An = Th–Cm): multiconfigurational studies and topological analysis" (PDF). RSC Advances. 4 (24): 12078–12086. Bibcode:2014RSCAd...412078K. doi:10.1039/C3RA47088A.

Category:Protactinium compounds Category:Organoactinide compounds Category:Metallocenes