Cerocene

Cerocene is a organometallic complex with the chemical formula Ce(C₈H₈)₂ (Ce(cot)₂).^[1][2] It is a sandwich compound consisting of a central cerium atom and two cyclooctatetraenide rings.

Cerocene

Names
Other names Cerium di-cyclooctatraene
Identifiers
CAS Number	37205-27-9
3D model (JSmol)	Interactive image
InChI Key: XMGBAYFIOLSVIM-YTBUGUEYSA-N InChI=1S/2C8H6.Ce/c2*1-2-4-6-8-7-5-3-1;/h2*1-3,6-8H;/q2*-2;+4/b2*2-1-,3-1?,8-6?,8-7-;
SMILES C\1=C\[C-]=C/C=C\[C-]=C1.C\1=C\[C-]=C/C=C\[C-]=C1.[Ce+4]
Properties
Chemical formula	Ce(C8H8)2
Molar mass	348.423
Appearance	red crystal
Melting point	290 °C (With Decomposition)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

Cerocene can be prepared by reducing cerium(III) di-cyclooctatraene anion salts:^[1]

Ce(C₈H₈)₂K → Ce(C₈H₈)₂ + K⁺

Chemical properties

Cerocene decomposes when exposed to water or oxygen to yield non-stoichiometric cerium-oxides and cyclooctratraene derivitives.^[2]

It undergoes a disproportionation, leading to an equilibrium between cerocene and a double-decker structure containing two cerium atoms:^[2]

2 Ce(C₈H₈)₂ ⇌ Ce₂(C₈H₈)₃ + C₈H₈

Although the cyclooctatetraenide ligand is usually considered a dianion and therefore cerocene is identified as a Ce(IV) complex, theoretical and experimental analysis of the compound indicates that is more correctly described containing a Ce(III) atom.^[1]

Related compounds

Cerocene is a known precursor for uranocene, U(C₈H₈)₂:^[1]

Ce(C₈H₈)₂ + UCl₃ ⇌ U(C₈H₈)₂ + CeCl₃

Cerocene is commonly confused with the compound tris(cyclopentadienyl)cerium.