Moscovium (Mc, atomic number 115) is a synthetic superheavy element. Since it is extremely unstable and radioactive, existing only for fractions of a second after creation, no human has ever seen a bulk sample or even a single atom. Therefore, any description of what moscovium “looks like” relies entirely on sophisticated theoretical predictions based on its position in the periodic table and the laws of physics. This theoretical modeling is the only way to gain insight into the physical and chemical properties of this fleeting substance.
Moscovium’s Identity: A Synthetic Superheavy Element
Moscovium (Mc) has 115 protons in its nucleus, placing it in the seventh period of the periodic table. It is classified as a synthetic element, meaning it does not occur naturally on Earth and must be created in a laboratory setting through nuclear fusion reactions. This distinction is important because all of its atoms are produced one at a time and decay rapidly.
The element is situated in Group 15, making it the heaviest member of the pnictogen group, which also includes nitrogen, phosphorus, and bismuth. It was first synthesized in 2003 by a joint team of Russian and American scientists at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The discovery was recognized by the International Union of Pure and Applied Chemistry (IUPAC) in 2015, and it was officially named moscovium in 2016, honoring the Moscow Oblast where the research facility is located.
Its placement in the p-block suggests it should share characteristics with its lighter homologues, particularly bismuth, the heaviest stable pnictogen. However, as a superheavy element, its properties are significantly altered by relativistic effects. These effects cause moscovium to deviate from expected trends based on its position in the periodic table.
Predicted Physical and Chemical Traits
Since direct observation is impossible, scientists use advanced quantum mechanical models to predict moscovium’s physical appearance and chemical behavior. These models consistently predict that moscovium would be a dense metal and a solid at room temperature. Its predicted density is approximately 13.5 grams per cubic centimeter, a value comparable to that of lead or bismuth.
The theoretical color of moscovium is predicted to be metallic gray or silvery white, similar to many other metals. However, the extreme speed of its inner electrons introduces strong relativistic effects that influence its electronic structure. These effects can dramatically alter the way an element absorbs and reflects light, potentially causing a color that is darker or more unusual than a typical silvery metal.
Relativistic effects are expected to stabilize the s- and p-orbitals in the outermost electron shells, which significantly impacts its chemical reactivity. Moscovium is predicted to exhibit a stable +1 oxidation state, a trait it shares more closely with thallium (Group 13) than with its direct neighbor bismuth (Group 15). Conversely, the classic Group 15 oxidation state of +5 is predicted to be its most common, although the stability of this state is reduced compared to its lighter pnictogen cousins. Initial experiments on its chemical reactivity confirm the role of relativistic effects in its behavior.
Production and Ephemeral Existence
Moscovium is synthesized using a “hot fusion” reaction within a particle accelerator. The specific method involves bombarding a target of americium-243 (element 95) with a beam of calcium-48 ions (element 20). When the nuclei successfully fuse, they create a highly energetic compound nucleus that quickly sheds neutrons to form an atom of moscovium.
The most stable known isotope, moscovium-290, has a half-life of only about 0.65 seconds, while others last only milliseconds. This rapid decay ensures that half of the created atoms transform into other elements in less than a second. Only a few hundred atoms of moscovium have ever been created and detected.
The atoms are detected only by tracking the unique chain of alpha-particle decays they produce as they transform into lighter, more stable elements. This rapid decay, combined with the minute quantity, makes it impossible to gather enough material to measure properties like melting point or to observe its physical appearance visually.