Page 159 - Academic Press Encyclopedia of Physical Science and Technology 3rd InOrganic Chemistry

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Encyclopedia of Physical Science and Technology EN007D-343 July 10, 2001 20:13

Inorganic Exotic Molecules

Joel F. Liebman Kay Severin
University of Maryland, Baltimore County Thomas M. Klap¨otke
Ludwig Maximilians University of M¨ unich

I. Atoms and the Nature of Matter VII. Polyphosphorus and Polynitrogen Species,
II. Hydrogen and the Alkali Metals Their Analogues and Derivatives
III. Cations and/or Anions: Plemeioelectronic VIII. Noble Gases
and Hermaphroditic Species IX. Transition Metal Complexes with Exotic
IV. Three-Atom 16-Valence-Electron XYZ Species: Ligands and Geometries
Isoelectronic Analogues X. Nano-Sized Molecules: Clusters, Fullerenes,
V. Ethylene and Beyond: Analogues, Cages, and Self-Assembled Metal Complexes
and Cleavage XI. Conclusion
VI. Reversing the Squashing: Boron Hydrides

GLOSSARY HEDM (high-energy-density material) Species with
highly exothermic decomposition pathways as well
Alkalide Salt in which one of the alkali metals is the as high material density. As applied to fuels and ex-
anion. plosives, respectively, more Btu’s and bang to the
Connectivity The set of connections between atoms, barrel.
where no distinction is made between single, multiple, Hermaphroditic species Two species having the same
or fractional bonds. composition and connectivity, but with opposite
Fullerene Ball-shaped cluster or cage of interconnected charges.
2
trigonal or sp carbon atoms. Derivatives include re- Homopolyatomic A group, ion, or molecule composed
placement of some carbons by hetero atoms, the pres- of only one type of atom.
ence of atoms inside the cluster/cage, and functional- Increased valence structure See Harcourt structure.
ization by reactions involving the formal double bonds Isoelectronic species Two species having the same num-
connecting the carbons. ber of electrons and the same number and the same
Harcourt structure Valence structures that involve more connectivity of heavy atoms.
electrons in bonding than Lewis structures that are lim- Lewis structure A valence-bond structure that has (a)
ited to electron-pair bonds and electron lone pairs (also the maximum number of electron-pair bonds permit-
“increased valence structure”). ted by the rules of valence (e.g., the Lewis–Langmuir
Heavy atom Any atom other than hydrogen. octet rule for first-row elements) and (b) places electron

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