Valency subsidiary

Valency Isomerism.—This type of isomerism is possible in the dieobalt-aminines, depending on the position of the subsidiary valence that is, whether a bridging group is linked to both cobalt atoms by principal valencies or by one principal and one subsidiary valence. Tetraethylenediamino-p-amino-peroxo-dicobaltic salts,... 

Valency isomerism is possible, depending on whether the bridging nitrogen of an amino-group is linked to one cobalt atom through a principal valency bond, and to the other cobalt atom by a subsidiary valence, as in the formula... 

The term subsidiary valency forces is also used to indicate the interaction through Van der Waals forces, including the hydrogen bond formation (p. 369) in contrast to the stronger atomic and ionic bonding forces. Thus one says that the bonding in one molecule of a polymer is due to principal valency forces, the mutual connection between the molecules is attributed to the so-called subsidiary valency forces. 

It is probable that peculiarities in the behaviour of other compounds which contain adjacent dipoles may be capable of explanation along these lines, whereas hitherto the most that could be done to explain them has been to bring forw ard hazy ideas of subsidiary valencies... 

The final paper (44) reported the finding that nitro compounds such as trinitromesitylene and tetranitromethane give colors with aromatic hydrocarbons and amines. Saturated aliphatic compounds give no color with tetranitromethane, but unsaturated aliphatic compounds act like hydrocarbons as long as the ethylene link does not adjoin a carboxyl group. Werner concluded that the colored compounds result from the interaction of subsidiary valencies associated with the nitro group on one hand, and... 

Werner himself later spoke (26) of his own work on acetylacetonates of platinum as having anticipated this concept of "Innerkomplexe", in which the charged (main valency) and uncharged (subsidiary valency) ligands are part of one and 3ie same molecule. Certainly the stereochemical consequences of chelation at a metal ion,... 

Each sp -hybridized carbon atom combines with three other sp -hybrid-ized atoms to form a series of hexagonal structures, all located in parallel planes as shown schematically in Fig. 2.16. The fourth valency, that is, the free delocalized electron, is oriented perpendiculartothis plane as illustrated in Fig. 2.17. Unlike the sigma (c orbital, it is non-symmetrical and is called by convention a pi (jt) orbital. It is available to form a subsidiary pi (n) bond. 

The sp orbital (known as a digonal orbital) is a merger of an s and a p orbital which consists of two lobes, one large and one small, as illustrated in Fig. 2.18. An sp bond consists of two sp orbitais which, because of mutual repulsion, form an angle of 180° and, consequently, the sp molecule is linear. The bond, like all overlap bonds, is a sigma (a) bond and has high strength. The sp orbitals account fortwo of the electrons of the carbon atom. The other two valence electrons are free, delocalized pi n) orbited electrons which are available to form subsidiary pi (n) bonds in a manner similar to the sp hybridization. 

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