Flerovium (Fl), a synthetic element with atomic number 114, is a superheavy element located at the far reaches of the periodic table. It is highly radioactive and extremely unstable, with its longest-lived isotopes decaying after only a few seconds. Because scientists have only ever created a handful of atoms, studying its fundamental properties is exceptionally difficult. The central question is whether Flerovium behaves like a standard metal, as its position suggests, or if its immense size alters its chemical nature entirely.
Creating Element 114
Flerovium is not found anywhere on Earth and must be produced artificially in high-energy particle accelerators. The process involves nuclear fusion, where scientists fire a beam of lighter nuclei at a heavy target nucleus. This immense collision briefly fuses the two nuclei to create the new superheavy element.
The initial successful synthesis of element 114 occurred in a collaboration between the Joint Institute for Nuclear Research (JINR) in Russia and the Lawrence Livermore National Laboratory (LLNL) in California. The team accelerated calcium-48 nuclei into a target composed of plutonium-244. This precise bombardment yielded the first atoms of Flerovium, named in honor of the Flerov Laboratory of Nuclear Reactions. Isotopes like Flerovium-289 have half-lives around 2.6 seconds, which is long enough for scientists to detect and study their decay products.
The challenge of creating superheavy elements is highlighted by the sheer effort required to produce even one atom. For instance, early experiments fired five billion billion calcium ions at the target over a period of 40 days to create a single atom of the element. Due to the element’s short half-life, researchers must perform chemical experiments on a one-atom-at-a-time basis, analyzing its behavior immediately before it decays.
Theoretical Predictions of Chemical Behavior
Based on the periodic table’s structure, Flerovium is located in Group 14, directly below the element lead (Pb). Following the established trend down this group—from carbon to silicon, germanium, tin, and lead—each successive element shows an increase in metallic character. Standard chemical theory would therefore predict that Flerovium should behave like a heavy, post-transition metal, similar to lead.
However, the enormous number of protons (114) packed into the Flerovium nucleus introduces a phenomenon known as the relativistic effect. The high positive charge of the nucleus causes the inner shell electrons to accelerate to speeds approaching the speed of light. This extreme velocity dramatically increases the mass of these electrons, which in turn alters the energy and shape of the outer valence electron orbitals.
Specifically, the relativistic effect causes the outer valence electrons in the 7s and 7p1/2 orbitals to be pulled closer to the nucleus and become much more tightly bound. This stabilization creates a large energy gap, which makes the valence electrons significantly less available for the chemical bonds typically formed by metals. Theorists predicted this effect would make Flerovium highly unreactive, suggesting it might behave more like an inert gas or a very volatile liquid, rather than a dense, solid metal.
Experimental Evidence and Classification
To test these competing predictions, researchers performed gas-solid chromatography experiments, measuring how strongly single Flerovium atoms interact with surfaces like gold. A typical metal like lead forms a strong bond and sticks readily to the surface. Conversely, an inert gas like radon barely interacts and flies through the apparatus unless heavily chilled.
The experimental results confirmed that Flerovium does not behave like its lighter, metallic cousin lead. Instead, Flerovium was found to be extremely volatile, requiring very low temperatures to condense and adhere to the gold surface. Its measured adsorption behavior was less reactive than the volatile metal mercury, yet more reactive than the noble gas radon.
This empirical evidence supports the theoretical prediction that the relativistic effects significantly diminish Flerovium’s metallic character. The current scientific consensus classifies Flerovium as the most volatile metal on the periodic table. While it is capable of forming weak chemical bonds, its inertness and high volatility mean it functions more like a volatile element with some metallic properties than a traditional, heavy metal.