Boron can exist in different forms, but it was unclear which one is stable at normal conditions. By studying the energies of two boron structures, researchers found that the more complex β‐boron is actually more stable than the simpler α‐boron at temperatures up to 2000 K. Below 1000 K, β‐boron is stabilized by its structure, while at higher temperatures it is stabilized by its energy. Only when pressure is applied does α‐boron become stable.