Complex sentence: Lead tetrafluoride, a yellow crystalline powder, is stable, but less stable than the difluoride; lead tetrachloride decomposes at room temperature; lead tetrabromide is less stable still; and existence of lead tetraiodide is questionable.
Split into simpler sentences: Lead tetrafluoride, a yellow crystalline powder, is stable, but less stable than the difluoride. Lead tetrachloride decomposes at room temperature, lead tetrabromide is less stable still and the existence of lead tetraiodide is questionable.