Subvalent compounds

Nuclear quadrupole resonance spectroscopy, see also specific compounds cyclophosphazenes, 21 93 of subvalent compounds, 29 298, 308-309 transition metal nitrosyl complexes, 34 313-314... 

Bredig [67] considered two categories of metal-molten salt mixtures metallic and nonmetallic solutions. In metallic solutions the metal dissolves without interacting strongly with the melt. Metal ions and partially free electrons are formed. The electrical conductivity of these mixtures increases strongly due to the presence of very mobile partially free electrons. Therefore an electronic conductivity appears in these melts. In nonmetallic solutions the metal reacts with the melt under the formation of subvalent ions or subvalent compounds. The electrical conductivity of these mixtures depends only to a small extent on the concentration of dissolved metal. The variation of properties of the metal-molten salt mixtures shows a continuous change from the metallic solutions to the nonmetallic if the temperature is sufficiently high. 

Multiple Bonding in Main Group Subvalent Compounds 12... 

A predominant characteristic of subvalent compounds is the presence of homonuclear element-element bonds. As a very simple example, trialkylaluminium, AIR3, contains Al(III), the normal oxidation state for this element. The dialane R2 Al-AIR2 contains an Al-Al single bond between two Al(II) centres, and as such can be considered to be a subvalent... 

The scope of main group subvalent compounds is broad and this article does not attempt to be comprehensive. Areas have been identified in which there have been... 

Finally, in terms of oxidation state formalisms subvalent compounds are often considered to be those for which 0 < Nok < m (where m is the group oxidation state), but in some cases it is also relevant to consider compounds for which Nox < 0. 

Formally subvalent compounds of boron containing a boron-boron single bond are intermediate in structural complexity between simple monoboron derivatives and the polyhedral electron-deficient compounds of the element. The properties of such compounds, particularly the simple derivatives of the B2X4 type, have attracted the attention of several groups of workers since Stock s initial discovery of BjCL some 45 years ago (96). These materials provide the simplest examples of catenation in boron chemistry and offer suitable systems in which to study the properties of the covalent B—B bond and the characteristic chemistry of compounds containing this linkage. 

Chapter 5 describes the chemistry of indium and thallium, including subvalent compounds of indium(II), thallium(II), and thallium(I). Applications of indium and thallium complexes are also described. 

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