Three-dimensional hydrocarbon networks

Ion exchange is a fundamental form of chromatography that was invented by Adams and Holmes in 1935. They realized that synthetic organic polymers, or resins, were capable of exchanging ions with the solution that contained them. The framework of the early resins consisted of a three-dimensional hydrocarbon network with ionizable groups that impart a hydrophilic nature to the resin. The ionizable groups are either acidic or basic. 

Diamondoids, when in the solid state, melt at much higher temperatures than other hydrocarbon molecules with the same number of carbon atoms in their structures. Since they also possess low strain energy, they are more stable and stiff, resembling diamond in a broad sense. They contain dense, three-dimensional networks of covalent bonds, formed chiefly from first and second row atoms with a valence of three or more. Many of the diamondoids possess structures rich in tetrahedrally coordinated carbon. They are materials with superior strength-to-weight ratio. 

The mechanical strength of polymers is achieved through extensive cross-linking whereby a three-dimensional network of hydrocarbon chains is formed. Depending... 

As a function of temperature, and up to 350 °C in some cases, magnesium and cadmium soaps exhibit only one or two eylindrical structures, whereas calcium soaps present both different successive struetures with disk and cylinders. These two classes of structure are found also in strontium and barium soaps, with, in addition, a body-centered cubic structure. These cubic phases have interesting features in that the polar groups are present on rods of finite length which belong to two, interwoven, infinite three-dimensional networks and the hydrocarbon chains constitute a eontinuous, paraffinic matrix (Figure 45). 

---