Isotopes of beryllium

Beryllium is a very light metal, lighter than most other metals, and it has the atomic number 4 on the periodic table.^[1] On Earth, all naturally found beryllium is the same type, called beryllium-9. This means it does not come in different stable forms like some other elements do.^[2] However, in laboratories, scientists have created other forms of beryllium that are unstable, called radioactive isotopes. These versions do not last very long before breaking down. The stable version, beryllium-9, has a structure inside its nucleus that makes it unusual compared to other elements. It is not held together very tightly, so it can release particles called neutrons fairly easily. This made it useful in the early days of nuclear technology. For example, scientists once mixed beryllium with other radioactive elements to create sources of neutrons that were used in the first nuclear weapons.^[3]

Some radioactive types of beryllium appear naturally. One of these, called beryllium-7, is made in the atmosphere when cosmic rays from space hit gases like oxygen and nitrogen. It only lasts about 53 days before turning into another element, lithium. Because it appears and disappears so quickly, scientists use it to study things like soil movement, how particles travel through the air, and how sediments form in rivers and lakes. Another version, beryllium-10, is much longer-lasting, about 1.39 million years before it breaks down. It also forms in the atmosphere when cosmic rays strike gases. Over time, it collects in places like ice cores, soils, and sediments. Scientists use it to study Earth’s history, including past climates, geological events, and even changes in the Sun’s activity over thousands of years.

Some forms of beryllium are so unstable that they break apart almost instantly. For example, beryllium-6 disappears in less than a blink of an eye, and beryllium-8 exists for only a tiny fraction of a second. Despite this, beryllium-8 is very important in stars, where it helps allow helium atoms to fuse into carbon. Without this step, stars could not make carbon, and life as we know it would not exist. Other rare types, like beryllium-11, are interesting to scientists because they behave in unusual ways. In beryllium-11, one neutron orbits far away from the rest of the nucleus, almost like a satellite circling a planet. This strange behavior helps physicists learn more about how atoms work.

Even though only one type of beryllium occurs naturally, the different radioactive types play an important role in research. Scientists study them to learn about Earth’s processes and even the universe. However, beryllium is dangerous to handle because it is toxic if inhaled. Breathing in beryllium dust can cause a serious lung disease, so scientists must work with it very carefully in special labs.