Atomic Radii & Clustering Tendency: MgO & NiO

[benndamann33]

This is a general question, not specific to anyone homework problem just a concept I must understand in order to figure out all of my homework. Does clustering tendency increase as atomic radii between substances A and B become more similar? Clustering tendency may not be particularly clear. What I mean is if there is a substance A and B with very similar atomic radii, are they more likely to dislike each other or like each other. Let's say A is MgO and B is NiO. This now is a specific homework question, admittedly. It seems to me that A and B would like each other becuase the radius of Mg = radius Ni and therefore there would be a low clustering tendecny - that is MgO would not feel compelled to stay with other MgOs becuase NiO is a comparable substance. However MgO and CaO would want to self-cluster because they dislike each other because the radi between Mg and Ca is drastically different. Is this logic incorrect?

 

[Valkarie]

Your logic is correct. Generally speaking, substances with similar atomic radii will be more likely to like each other and have a lower clustering tendency than substances with very different atomic radii. The more different the radii, the higher the clustering tendency will be.

 

[piercas]

Your logic is correct. In general, substances with similar atomic radii are more likely to have a lower clustering tendency because they are more compatible in terms of their atomic size. This means that they are more likely to mix and form solid solutions rather than segregate into separate clusters.

In the case of MgO and NiO, their similar atomic radii would lead to a lower clustering tendency. However, as you mentioned, substances with drastically different atomic radii, such as MgO and CaO, are more likely to have a higher clustering tendency because their atomic sizes are not compatible and they are more likely to segregate into separate clusters.

It's important to note that clustering tendency is not the only factor that determines the compatibility of substances. Other factors such as electronegativity, bonding strength, and crystal structure also play a role. But in general, substances with similar atomic radii are more likely to have a lower clustering tendency.