What was the definitive sorting mechanism that separated the three primary material classes in the nebula?

Answer

The temperature gradient across the protoplanetary disk.

The variation in temperature, being extremely hot near the center and cooling steadily outward, established a clear chemical sorting that dictated where the different classes of materials could condense.

What was the definitive sorting mechanism that separated the three primary material classes in the nebula?
Spaceastronomycompositionsolar systemformationcomponentssolar nebulaPlanetary Formation