Which materials condensed near the hot proto-Sun to form terrestrial planets?

Silicates and metals

The structure of the protoplanetary disk established a significant temperature gradient, being extremely hot near the nascent central star (the proto-Sun) and gradually cooling further out. In the hot inner regions, only materials capable of remaining solid at high temperatures could condense out of the gaseous mixture. These refractory materials are primarily silicates (rock-forming minerals) and metals, such as iron and nickel. Because volatile compounds like water, methane, and ammonia required much lower temperatures to condense into solids, they remained gaseous near the proto-Sun, meaning the inner solar system was restricted to accumulating only rocky and metallic grains, leading directly to the formation of the dense, smaller terrestrial planets.