Linked Life Data

18331027

Source:http://linkedlifedata.com/resource/pubmed/id/18331027

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
13
pubmed:dateCreated
2008-3-26
pubmed:abstractText
Fullerene C60 monomer crystals were compressed to a face-centered cubic (fcc) phase with a lattice parameter of a = 11.93(5) A and a micro-Vickers hardness of 4500 kg/mm2 using high-pressure and high-temperature conditions of 15 GPa at 500-600 degrees C. The hardness is compatible with that of cubic boron nitride (c-BN), suggesting the formation of a 3D C60 polymer. The single-crystal X-ray structural analysis revealed that each C60 molecule in the polymer was linked to the 12 nearest neighbors by [2+2] cycloaddition between the common pentagon-hexagon (56) edges. However, ab initio geometry optimization and molecular dynamics calculations suggested that the 3D polymer should have a rhombohedral structure with the space group of R containing [3+3] cycloaddition between the pentagons of C60 molecules within the plane perpendicular to the 3-fold axis. The higher apparent symmetry of fcc was observed as an averaged structure of different orientations of the rhombohedral structure. The R structure can be derived by only a slight rotation of each C60 unit in the (111) plane of the fcc structure. The band-structure calculation suggested that the 3D polymer (R) was a semiconductor; the activation energy for the electrical conductivity was experimentally determined to be 0.25 eV at 550 K.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1520-5126
pubmed:author
pubmed:issnType
Electronic
pubmed:day
2
pubmed:volume
130
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4303-9
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Topochemical 3D polymerization of C60 under high pressure at elevated temperatures.
pubmed:affiliation
Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't