# Can alloys or ceramics have higher density than elemental solids?

Are there any examples of alloys or ceramics that have higher density than their densest elemental constituent? If so, do they have unusual or difficult synthesis processes? If not, is it provable that this is not possible, or demonstrably unlikely.

Since homogeneous metals are essentially crystals in their solid phase it seems plausible that, in theory, there are elements that could fit within the crystal structure without altering it to increase their density.

This would be particularly interesting for metals that are used in applications primarily for their density: e.g., lead, tungsten, and uranium.