Greetings,
Network solids consist of certain nonmetal element atoms and molecules which are covalently bonded, resulting in an ordered array. In a sense, the individual atoms or molecules lose their identities because they are surrounded by other atoms or molecules forming a pure substance, the "same everywhere".
Many network solids are commonly known and, therefore, taken for granted. For example, pencil lead and a diamond are normally considered to be different substances.........but, they're both manifestations of the same element; carbon! How is this possible?! The answer is found in the network structures of pencil lead and a diamond; single bonded tetrahedral atom-arrangement for diamond and flat-conjugated fused-hexagonal sheets weakly connected as layers via p-atomic orbital sigma bonding for pencil lead.
Diamond's 100% covalent bonding and network of connected tetrahedral units results in an exceedingly strong structure. I use a ball (wooden) and stick (steel rods) model of diamond's atomic-level structure when I teach on the allotropes of carbon. To demonstrate the strength of the diamond geometry, I put the model on the floor and I, literally, stand on the model, using one foot. I balance my approx. 200 lb frame on the model and the tetrahedral network structure easily supports me!
On the other hand, pencil lead (aka, a pressed mixture of graphite and clay) easily breaks, as witnessed by heavy-handed writers everywhere! If one were to carefully observe the resulting broken "lead", smooth, flat faces would be seen. On the smallest scale, the fused ring sheets which make up carbon-graphite are easily "torn-away" from each other. This separation of layers results in the flaked-broken pieces observed at our macroscopic scale upon pressing too hard on pencil lead!
That's all for this post. Have a good one!
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