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How does the continuous random-network model describe amorphous silicon dioxide?

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The continuous random-network model describes the atomic-scale structure of amorphous silicon dioxide (silica glass) by demonstrating how short-range order is maintained despite the absence of long-range order.1

In this model, the structure is defined by specific bonding arrangements: each silicon atom is bonded to four oxygen atoms, and each oxygen atom is bonded to two silicon atoms. This creates a network where the bond angles at the bridging oxygen atoms possess enough flexibility to allow the network to continue in a non-periodic, amorphous fashion.1

While the model is often illustrated using two-dimensional analogies, it represents a three-dimensional network where the local coordination—such as the tetrahedral arrangement of neighbors around a silicon atom—remains consistent with the material's chemical identity. This structure is not truly random in the sense of a gas; rather, it is a well-defined, covalently bonded network that lacks the repeating, periodic symmetry found in crystalline forms like quartz.1