What Are the Basic Rules for Naming Elements?

Every new chemical element must be named according to a formal set of guidelines maintained by the International Union of Pure and Applied Chemistry (IUPAC). The rules specify who gets to propose a name, what categories of inspiration are allowed, and even what the last few letters of the name must be depending on where the element sits in the periodic table. These guidelines have been refined over decades and were most recently updated from a 2002 set of recommendations, but the core framework is straightforward enough to fit on a single page.

Five Allowed Categories of Inspiration

IUPAC restricts the source of an element’s name to five categories. A new element can be named after a mythological concept or character, a mineral or similar substance, a place or country, a property of the element, or a scientist.¹ That list might sound broad, but it serves a real filtering function. You cannot name an element after a living corporate brand, a fictional character from a movie, or an inside joke from the laboratory.

In practice, the five categories have produced a periodic table with a pleasantly eclectic mix of origins. Elements named after properties include hydrogen (from Greek words meaning “water-former”) and chlorine (from the Greek word for “greenish-yellow,” describing the color of the gas). Elements named after places range from francium and germanium to tennessine, which honors the state of Tennessee and the research facilities located there. Elements named after scientists include einsteinium, curium, and oganesson, the last of which was named for the nuclear physicist Yuri Oganessian while he was still living. Mythological names go back to older elements like thorium (after Thor) and newer ones like promethium (after Prometheus).

The mineral category tends to appear less often in modern element naming, partly because the newest elements are all synthetic and never found as minerals in nature. But for elements discovered in the 18th and 19th centuries, the mineral a substance was first isolated from was a common and intuitive source of names.

How the Ending of an Element’s Name Is Determined

One of the most specific rules in the IUPAC guidelines governs the suffix attached to every element name. The required ending depends on which group (column) of the periodic table the element belongs to. Elements in groups 1 through 16 must end in “-ium.” Elements in group 17 (the halogens) must end in “-ine.” Elements in group 18 (the noble gases) must end in “-on.”¹ The purpose is to maintain what IUPAC calls “historical and chemical consistency,” meaning the suffix immediately tells a chemist something about where the element lives on the periodic table and what kind of chemistry it does.

You can see this pattern in the most recently named elements. Nihonium (element 113, group 13) ends in “-ium.” Tennessine (element 117, group 17) ends in “-ine.” Oganesson (element 118, group 18) ends in “-on.” The suffix rule was reinforced in the updated recommendations specifically because earlier naming episodes had occasionally produced inconsistencies that the community found confusing.

Plenty of older element names do not follow these suffix rules. Oxygen, carbon, iron, gold, and sulfur all predate any organized naming system. IUPAC does not retroactively rename established elements; the suffix guidelines apply only to newly discovered elements going forward. This is why the periodic table reads as a blend of ancient names and systematically constructed modern ones.

Who Gets to Propose a Name

The privilege of proposing a name belongs to the discoverers. After a new element’s discovery has been verified and accepted by a joint working group of IUPAC and the International Union of Pure and Applied Physics (IUPAP), the discovery team is formally invited to suggest both a name and a chemical symbol for the element.² This is considered one of the major honors in experimental physics and chemistry, roughly equivalent to having a species named after you in biology, but with far fewer opportunities.

The process is not instantaneous. Confirming a new element can take years, and the naming step comes only after that confirmation is complete. In the case of elements 113, 115, 117, and 118, the discoveries were confirmed in late 2015 and early 2016, but the official names were not finalized until later that same year, after proposals were submitted, reviewed, and put through a public comment period.

Discoverers generally consult among their teams and sometimes with the broader community before making their proposal. The choice often reflects the national identity of the research institution. Nihonium (element 113, discovered at RIKEN in Japan) takes its name from “Nihon,” the Japanese word for Japan. Moscovium (element 115) honors Moscow and the region where the Joint Institute for Nuclear Research is located. These naming choices carry national pride and scientific diplomacy, and research teams take them seriously.

The Approval Pipeline

A proposed name does not become official the moment it is submitted. The proposal first goes to IUPAC’s Inorganic Chemistry Division for examination. The Division checks that the name conforms to the five allowed categories, uses the correct suffix, and does not conflict with any existing element names. If accepted by the Division, the proposal enters IUPAC’s standard approval procedure, which includes a five-month public review period during which scientists and the general public can submit comments and objections. The name is then ratified by the Council of IUPAC, which is the organization’s governing body.¹

The public review period has occasionally generated real debate. When the names for elements 113, 115, 117, and 118 were proposed in 2016, thousands of comments poured in during the review window. Some members of the public lobbied for alternative names, and online campaigns circulated proposing everything from “lemmium” to names honoring popular cultural figures. None of these campaigns changed the outcome, but the review period does give the broader scientific community a genuine opportunity to flag problems, such as a name that might be easily confused with an existing element or a symbol that clashes with an established abbreviation.

Rules for Chemical Symbols

Alongside the name, discoverers propose a one- or two-letter chemical symbol. The first letter must be capitalized, and if there is a second letter, it must be lowercase. The symbol should derive from the proposed name, though the connection is sometimes loose. For recently named elements, the link is usually obvious: Nh for nihonium, Mc for moscovium, Ts for tennessine, Og for oganesson.

Symbol selection has to avoid duplicating any existing symbol on the periodic table, and it should be reasonably easy to distinguish visually and typographically from other symbols. This is partly practical. Chemists writing reaction equations by hand need to be able to tell symbols apart quickly, and symbols that look too similar on a printed page or a handwritten note invite errors. While there is no formal IUPAC rule banning every possible similarity, the Inorganic Chemistry Division reviews proposed symbols with readability and distinctiveness in mind.

Some older elements have symbols that bear no relationship to their English names. Gold is Au (from the Latin “aurum”), lead is Pb (from “plumbum”), and sodium is Na (from “natrium”). These symbols were inherited from Latin or other historical naming traditions and predate the IUPAC system. For new elements, the expectation is that the symbol will connect transparently to the approved English name.

Temporary Placeholder Names

Between the moment a new element is reported and the moment it receives an official name, it needs something to be called. IUPAC handles this with a systematic placeholder naming convention. Each placeholder name is constructed from the element’s atomic number using Latin and Greek roots for each digit: “un” for 1, “bi” for 2, “tri” for 3, “quad” for 4, “pent” for 5, “hex” for 6, “sept” for 7, “oct” for 8, “nil” for 0, and “enn” for 9. These roots are strung together, and the name always ends in “-ium.”

Under this system, element 118 was temporarily called “ununoctium” (un-un-oct-ium) before it became oganesson. Element 113 was “ununtrium.” These names are deliberately bland and unambiguous. They carry no national, personal, or mythological freight, which is the point. They are parking spots, not permanent identities. Placeholder symbols follow the same logic: Uuo for ununoctium, Uut for ununtrium. Once the official name is approved, the placeholder disappears from all IUPAC publications and recommended tables.

For elements that remain unconfirmed or whose discovery claims are still being evaluated, the placeholder name is the only name in circulation. This can persist for years. Some placeholder names have spent enough time in textbooks and databases that they develop a kind of informal familiarity, which makes the switch to a permanent name feel a bit jarring to people who learned the placeholder first.

How Elements Were Named Before the Rules

The formal IUPAC naming framework is a modern invention. For most of the history of chemistry, element names were assigned by their discoverers with no standardized process and no oversight body. The result is a periodic table full of names that reflect the personal preferences, national allegiances, and sometimes the quirks of individual chemists spread across several centuries.³

Elements known since antiquity, like gold, silver, copper, and iron, were named in various languages long before anyone understood them as elements. Their names evolved organically through centuries of trade and alchemy. When systematic chemistry emerged in the 17th and 18th centuries, new elements started receiving names more deliberately, but there was no international body to coordinate. Antoine Lavoisier pushed for names based on chemical properties (hence “oxygen,” meaning “acid-former,” and “hydrogen,” meaning “water-former”), but other chemists preferred names honoring places or minerals. Some elements were named and renamed multiple times as different national traditions clashed.

The naming wars got particularly heated in the 20th century around the transfermium elements, those beyond fermium on the periodic table. American and Soviet research teams both claimed priority for discovering several elements and proposed competing names. Element 104 was called “rutherfordium” by the Americans and “kurchatovium” by the Soviets. Element 105 was “hahnium” in the American proposal and “dubnium” in the Soviet one. These disputes dragged on for decades and were not fully resolved until the 1990s, when IUPAC convened special committees to adjudicate the claims and assign official names. The experience was messy enough that it motivated the community to tighten and formalize the naming procedures that exist today.

What the Rules Quietly Forbid

The five permitted categories implicitly exclude a number of naming possibilities that occasionally come up in public discussion. You cannot name an element after a commercial brand or a product. You cannot name one after a living person who is not a scientist, which means no “beyoncium” regardless of how many online petitions circulate. You cannot name an element after a fictional character from popular culture, since fictional characters do not fit any of the five categories unless they are from mythology.

There is also an unwritten but well-observed norm against naming elements after yourself. Discoverers nominate names, and choosing your own name would be considered poor form within the scientific community. The tradition is to honor other scientists, usually deceased ones. The exception is extremely rare: oganesson was named after Yuri Oganessian, who was still alive at the time, but the proposal came from his collaborators rather than from Oganessian himself, and it recognized decades of contributions to superheavy element research.

IUPAC also discourages names that would be difficult to pronounce or transliterate across the world’s major languages. Since the periodic table is used globally, a name that works well in English but is nearly unpronounceable in Mandarin, Arabic, or Russian poses real practical problems. This is not a hard veto, but the Inorganic Chemistry Division considers linguistic accessibility during its review.

Why Some Older Names Break the Modern Rules

If you look at the periodic table with the current IUPAC rules in mind, several familiar names stick out as violations. Helium is a noble gas in group 18, so under today’s rules it should end in “-on,” but it was named in the 19th century, long before the suffix convention existed. Similarly, argon follows the “-on” convention correctly, but that is partly coincidental since its name comes from the Greek word “argos” meaning “idle” or “lazy,” a reference to its chemical inertness. Neon happens to fit as well, since its name comes from the Greek “neos” for “new.”

The halogens also show the pattern’s imperfect history. Fluorine, chlorine, bromine, iodine, and astatine all end in “-ine” or “-ine”-adjacent sounds, but this consistency was not legislated; it evolved by convention over a century of chemical naming. The formalization of the “-ine” rule for group 17 essentially codified what chemists had already been doing. The “-ium” rule for most of the periodic table is similarly grounded in tradition. Latin endings were the default in 18th- and 19th-century science, and IUPAC’s modern guidelines preserve that convention rather than inventing something new.

IUPAC has never attempted to go back and rename older elements for consistency, and there is no indication it ever will. The practical disruption would be enormous. Every textbook, every journal article, every database, every chemical label in every language would need updating. The existing names are too deeply woven into the fabric of chemistry. The rules apply at the frontier, to elements that have not yet been named, where consistency can be established without rewriting the past.

The Race for Elements 119 and Beyond

As of now, all 118 known elements have been officially named, leaving no vacancies on the periodic table. But research teams in Japan, Russia, and the United States are actively trying to synthesize elements 119 and 120, which would open a new row (period 8) on the table. If and when those elements are confirmed, the naming rules described above will apply. Element 119, belonging to group 1, would receive an “-ium” ending. Element 120, in group 2, would also end in “-ium.” Their placeholder names are already assigned: ununennium (Uue) for 119 and unbinilium (Ubn) for 120.

Synthesizing superheavy elements is extraordinarily difficult. Atoms of these elements exist for fractions of a second before decaying, and producing even a handful of atoms requires months of particle accelerator time. The confirmation process, which demands that another laboratory independently reproduce the result, adds years to the timeline. It is entirely possible that the next batch of new element names will not arrive for another decade or longer, but when they do, the proposals will go through the same IUPAC pipeline: discoverers propose, the Inorganic Chemistry Division reviews, the public comments, and the Council ratifies.

What will those names be? No one outside the discovery teams knows, and the teams themselves may not have settled on choices yet. If past patterns hold, expect at least one name honoring a place associated with the research, at least one honoring a scientist, and possibly one drawing on a property of the element or a concept from mythology. The conventions are clear enough that the real suspense is not what form the name will take, but which specific people, places, and ideas the discoverers will choose to immortalize on the periodic table’s newest line.