Search results
Results From The WOW.Com Content Network
These groups are characterized by i) an n-fold proper rotation axis C n; ii) n 2-fold proper rotation axes C 2 normal to C n; iii) a mirror plane σ h normal to C n and containing the C 2 s. The D 1h group is the same as the C 2v group in the pyramidal groups section. The D 8h table reflects the 2007 discovery of errors in older references. [4]
, and Sc 3+ and the anions Cl −, S 2−, and P 3− are all isoelectronic with the Ar atom. CO, CN −, N 2, and NO + are isoelectronic because each has two atoms triple bonded together, and due to the charge have analogous electronic configurations (N − is identical in electronic configuration to O so CO is identical electronically to CN −).
Zintl phases are intermetallic compounds that have a pronounced ionic bonding character. They are made up of a polyanionic substructure and group 1 or 2 counter ions, and their structure can be understood by a formal electron transfer from the electropositive element to the more electronegative element in their composition.
The f-block groups are ignored in this numbering. [22] Groups can also be named by their first element, e.g. the "scandium group" for group 3. [22] Previously, groups were known by Roman numerals. In the United States, the Roman numerals were followed by either an "A" if the group was in the s-or p-block, or a "B" if the group was in the d-block.
The reactivity of a functional group can be modified by other functional groups nearby. Functional group interconversion can be used in retrosynthetic analysis to plan organic synthesis. A functional group is a group of atoms in a molecule with distinctive chemical properties, regardless of the other atoms in the molecule.
The isolobal analogy can also be used with isoelectronic fragments having the same coordination number, which allows charged species to be considered. For example, Re(CO) 5 is isolobal with CH 3 and therefore, [Ru(CO) 5] + and [Mo(CO) 5] − are also isolobal with CH 3. Any 17-electron metal complex would be isolobal in this example.
The compounds Co(NO)(CO) 3 and Ni(CO) 4 illustrate the analogy between NO + and CO. In an electron-counting sense, two linear NO ligands are equivalent to three CO groups. This trend is illustrated by the isoelectronic pair Fe(CO) 2 (NO) 2 and [Ni(CO) 4]. [3] These complexes are isoelectronic and, incidentally, both obey the 18-electron rule.
A chart or table of nuclides maps the nuclear, or radioactive, behavior of nuclides, as it distinguishes the isotopes of an element.It contrasts with a periodic table, which only maps their chemical behavior, since isotopes (nuclides that are variants of the same element) do not differ chemically to any significant degree, with the exception of hydrogen.