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A network solid or covalent network solid (also called atomic crystalline solids or giant covalent structures) [1] [2] is a chemical compound (or element) in which the atoms are bonded by covalent bonds in a continuous network extending throughout the material.
The covalent bonds in this material form extended structures, but do not form a continuous network. With cross-linking, however, polymer networks can become continuous, and a series of materials spans the range from Cross-linked polyethylene , to rigid thermosetting resins, to hydrogen-rich amorphous solids, to vitreous carbon, diamond-like ...
This hydrogen bond leads a string of acetic acid molecules hydrogen bonding to minimize free energy. [10] [26] These strings of acetic acid molecules then stack together to build solids. The halogen bonding between the bromine and 1,4-dioxane molecules partially guides the organization of the crystal lattice structure.
The properties of these physical networks are highly dependent on the used backbone and type of non-covalent interactions, but typically they are brittle at low temperature and become elastic or rubbery above T g. Upon further heating, the physical cross-links disappear and the material behaves as a visco-elastic liquid, allowing it to be ...
A covalent bond is a ... quantum mechanics is needed to understand the nature of these bonds and predict the structures and properties ... Network covalent ...
Very different bonding – strong covalent within the basal planes (planes where boron and nitrogen atoms are covalently bonded) and weak between them – causes high anisotropy of most properties of h-BN. For example, the hardness, electrical and thermal conductivity are much higher within the planes than perpendicular to them.
These links may take the form of covalent bonds or ionic bonds and the polymers can be either synthetic polymers or natural polymers (such as proteins). In polymer chemistry "cross-linking" usually refers to the use of cross-links to promote a change in the polymers' physical properties.
If a bond strength is higher than 80 kcal per bond (high bond strength), it will be glass network forming, meaning it is likely to form a glass. If a bond strength is less than 60 kcal per bond (low bond strength), it will be glass network modifying, since it would only form weak bonds, it would disrupt glass forming networks.