Atomic / phase data
Reference values are evaluated.
A7 structure
Gray antimony rhombohedral structure is measured.
Classification
Metalloid classification is conventional and context-dependent, not a physical constant.
Compound uses
Flame-retardant and semiconductor uses are identified as compound-specific.
Geography
Commodity context is dated/selective.
The lens describes evidence status, not confidence theatre. “Unknown” is kept unknown, and teaching schematics are not presented as direct measurements.
Antimony (Sb)
Antimony is element 51, symbol Sb: a brittle Group 15 metalloid whose symbol comes from the Latin stibium. Its A7 structure, +3/+5 chemistry and compound uses make it a strong case for separating an element from the materials that contain it.
Antimony atomic number, mass, electron configuration and key properties
Antimony: quick answers
How many protons, neutrons and electrons does antimony have?
Antimony’s atomic number is 51, so every antimony atom has 51 protons, and a neutral atom also has 51 electrons. Its most common natural isotope, antimony-121, has 70 neutrons (other isotopes have different neutron counts).
What is the symbol for antimony?
The chemical symbol for antimony is Sb.
Is antimony a solid, liquid or gas at room temperature?
Antimony is a solid at room temperature (about 25 °C).
What family (group) is antimony in?
Antimony is a metalloid, in group 15, period 5 of the periodic table.
How many valence electrons does antimony have?
Antimony has 5 valence electrons, the electrons in its outer shell, which matches its position in group 15.
What is the electron configuration of antimony?
The ground-state electron configuration of antimony is [Kr] 4d¹⁰ 5s² 5p³.
From atomic number to chemistry
Read these as a chain of causes, not as isolated facts. Each step links to the concept hub if you want the underlying idea explained.
51 protons define antimony.
The reference ground-state configuration frames atomic and chemical behavior.
Periodic position organizes recurring trends without replacing element-specific evidence.
The teaching nucleus is one isotope, not the relative atomic mass.
Phase claims preserve measured/evaluated/predicted/unknown evidence labels.
Antimony in its period and family
Antimony lies below arsenic and above bismuth in Group 15. Its 5s²5p³ valence pattern supports several oxidation states and a trend toward more metallic behavior down the group.
Antimony Visual Lab
Explore Sb across the teaching nucleus, isolated-atom orbitals, evidence-aware material structure and temperature/evidence views, then connect those models to uses, isotopes and source-backed context.
Every mark points to one exact feature
The numbered markers explain the same information system used throughout Element Lookup. Unknown or predicted fields remain visibly labelled rather than being replaced with guesses.
Antimony in one minute
Atomic number 51 means 51 protons.
Sb comes from the historical Latin name stibium.
Antimony is commonly classified as a metalloid.
Stable gray antimony is rhombohedral A7.
Antimony metal and antimony compounds can have very different uses and hazards.
Shell rings organize electron counts. They are not electron trajectories or orbital shapes.
2 · 8 · 18 · 18 · 5 electrons
The 5s/5p clouds are isolated-atom probability models. They do not depict bonding in Sb compounds or the band structure of crystalline antimony.
Stable gray antimony has the rhombohedral A7 structure. The viewer uses a simplified rhombohedral motif and does not represent molecular or compound allotropes.. The viewer is evidence-aware: measured structures are identified as such; unknown bulk structures stay unknown.
Teaching visualization; not a literal finite sample or thermal trajectory.What this model does—and does not—show
The 5s/5p clouds are isolated-atom probability models. They do not depict bonding in Sb compounds or the band structure of crystalline antimony.
Where do I meet antimony?
Clickable learning cards connect the element to materials, environment, technology, biology or research - depending on what the evidence actually supports.
Alloys
Antimony is used to harden or modify selected lead- and tin-based alloys.
Sb from stibium → A7 metalloid → compound-specific technology
Antimony connects historical naming to a Group 15 metalloid structure and shows why practical uses must distinguish elemental Sb from its compounds.
Sb = stibium
The chemical symbol preserves a historical Latin name rather than the English spelling.
Arsenic, antimony and bismuth
Five outer electrons persist while metallic character and the relative importance of +3/+5 chemistry evolve down the group.
| Class | metalloid |
|---|---|
| Structure | A7 gray |
| Class | metalloid |
|---|---|
| Structure | A7 gray |
| Class | metal |
|---|---|
| Structure | A7 |
Antimony properties: atomic, physical, thermal and chemical
Categories follow the science of this element rather than a fixed decorative template. Each row carries condition/provenance context and an evidence label; unknown values stay unknown.
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Atomic number | 51 | Source-reviewed; see Sources below | Evaluated |
| Relative atomic mass | 121.760 | Source-reviewed; see Sources below | Evaluated |
| Ground-state electron configuration | [Kr] 4d¹⁰ 5s² 5p³ | Source-reviewed; see Sources below | Evaluated |
| Group / period / block | Group 15 · Period 5 · p-block | Periodic-table placement | Evaluated |
| Electronegativity | 2.05 | Source-reviewed; see Sources below | Evaluated |
| Reference isotope | ¹²¹Sb | Source-reviewed; see Sources below | Evaluated |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| State context | Brittle silvery-gray metalloid | Source-reviewed; see Sources below | Evaluated |
| Density | 6.68 g/cm³ | Source-reviewed; see Sources below | Evaluated |
| Material / molecular structure | Rhombohedral · A7-type | Stable gray antimony has the rhombohedral A7 structure. The viewer uses a simplified rhombohedral motif and does not represent molecular or compound allotropes. | Measured |
| Classification | Metalloid | Periodic-table / chemistry classification | Evaluated |
| Structure-model scope | Stable gray antimony has the rhombohedral A7 structure. The viewer uses a simplified rhombohedral motif and does not represent molecular or compound allotropes. | Teaching visualization; exact crystallographic coordinates are not implied unless stated. | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Melting / transition reference | 903.778 K | Source-reviewed; see Sources below | Evaluated |
| Boiling / gas reference | 1860 K | Source-reviewed; see Sources below | Evaluated |
| Phase-path context | At approximately standard pressure, gray antimony is solid below 903.778 K, liquid to about 1860 K, and gaseous above the boiling reference. | Shared phase registry drives the slider, regions and markers. | Evaluated |
| Condition warning | Temperature and pressure define phase behavior; purity/allotropy may matter. | Teaching condition statement | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Common oxidation states | +5, +3, −3 | Source-reviewed; see Sources below | Evaluated |
| Ion / common ion context | Sb³⁺ | Source-reviewed; see Sources below | Evaluated |
| Periodic chemistry context | Antimony lies below arsenic and above bismuth in Group 15. Its 5s²5p³ valence pattern supports several oxidation states and a trend toward more metallic behavior down the group. | Element-specific interpretation | Reviewed |
| Chemistry caution | Elemental form, ions and compounds are distinct chemical objects. | Interpretive teaching rule | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| ¹²¹Sb | Stable natural isotope | Reference teaching nucleus with 51 protons and 70 neutrons. | Evaluated |
| ¹²³Sb | Stable natural isotope | The second stable natural isotope. | Evaluated |
| Natural antimony | Two stable isotopes | Relative atomic mass reflects their abundance mixture. | Evaluated |
| Teaching nucleus | ¹²¹Sb · 51 protons + 70 neutrons | Reference isotope used in the nucleus model | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Page evidence note | Atomic and ordinary phase values are evaluated. Gray-antimony A7 structure is measured; the viewer is schematic. Commodity geography is dated context and does not imply native-element deposits. | Evidence summary for this guide | Reviewed |
| Structure evidence | Stable gray antimony has the rhombohedral A7 structure. The viewer uses a simplified rhombohedral motif and does not represent molecular or compound allotropes. | Measured structure, labelled schematic, prediction or explicit unknown as applicable. | Reviewed |
| Map evidence rule | Real pins are reviewed examples; conceptual layers are used when pins would mislead. | Geography Explorer 2.0 | Reviewed |
| Source set | 3 primary/reference links listed below | Open the Sources section for the actual references. | Reviewed |
Is Antimony a solid, liquid or gas? State at temperature
At approximately standard pressure, gray antimony is solid below 903.778 K, liquid to about 1860 K, and gaseous above the boiling reference.
Where on Earth is Antimony found or produced?
Who discovered Antimony, and when?
Antimony sulfide minerals were used in pigments and cosmetics long before elemental chemistry was understood.
Metallic antimony and its compounds were described in European metallurgical texts.
Sb became the standardized symbol from stibium.
Antimony is important in alloys, compounds and critical-mineral supply discussions.
From antimony-bearing minerals to materials: high-level path
Antimony commonly occurs in minerals such as stibnite rather than as native bulk metal.
Industrial processing produces antimony metal or oxide/compound feedstocks.
Those feedstocks enter alloy, chemical and semiconductor supply chains.
Recycling and secondary recovery can contribute to supply; no extraction recipe is provided here.
What is antimony used for?
Alloys
Antimony modifies hardness and mechanical behavior in selected alloys.
Flame-retardant compounds
Antimony oxides can act in specific flame-retardant systems.
Semiconductors
Antimonide compounds are used in infrared and high-speed electronic materials.
Specialty chemicals
Antimony compounds have specialized catalytic, pigment and glass uses.
Antimony isotopes and natural abundance
¹²¹Sb
Stable natural isotopeReference teaching nucleus with 51 protons and 70 neutrons.
¹²³Sb
Stable natural isotopeThe second stable natural isotope.
Natural antimony
Two stable isotopesRelative atomic mass reflects their abundance mixture.
Five-question Antimony check
What is antimony’s symbol?
How is antimony commonly classified?
What is the ordinary gray structure?
Which oxidation states are important?
What must a use statement distinguish?
Antimony questions students commonly ask
Each answer starts with the direct fact, then explains the chemistry, evidence or material context so the result is understandable rather than merely memorized.
What is antimony?
Short answer: Antimony is chemical element 51, symbol Sb, commonly classified as a metalloid.
Atomic number 51 means every antimony nucleus contains 51 protons. In the periodic table, Antimony is classified here as a metalloid in Period 5 and Group 15. Antimony lies below arsenic and above bismuth in Group 15. Its 5s²5p³ valence pattern supports several oxidation states and a trend toward more metallic behavior down the group.
Key point: Sb is element 51; its periodic position and electron structure explain the rest of the page.
Why is antimony Sb?
Short answer: Sb comes from stibium, a historical Latin name associated with antimony.
The question “Why is antimony Sb?” is historical rather than electronic: Sb comes from stibium, the Latin name associated with antimony compounds. The symbol is not an abbreviation of the English word. Sb comes from the historical Latin name stibium.
Key point: The mechanism matters: connect the observed behavior to electron structure, bonding, phase or the specific material form rather than memorizing the result alone.
Is antimony a metal or metalloid?
Short answer: It is commonly classified as a metalloid, with a brittle metallic-looking elemental form.
This guide classifies Antimony as a metalloid. Its periodic position is Period 5, p-block, Group 15. Antimony lies below arsenic and above bismuth in Group 15. Its 5s²5p³ valence pattern supports several oxidation states and a trend toward more metallic behavior down the group.
Key point: Periodic-table classification describes recurring atomic/chemical behavior; it does not make every element in a column physically identical.
What is antimony used for?
Short answer: Antimony is used in alloys and, more often, through compounds in flame-retardant systems, semiconductors and specialty materials.
Alloys: Antimony modifies hardness and mechanical behavior in selected alloys. Flame-retardant compounds: Antimony oxides can act in specific flame-retardant systems. The question “Why is antimony Sb?” is historical rather than electronic: Sb comes from stibium, the Latin name associated with antimony compounds. The symbol is not an abbreviation of the English word.
Key point: Always distinguish the pure element from the compound, alloy, isotope or device material that actually performs the application.
Where is antimony found?
Short answer: It commonly occurs in antimony minerals such as stibnite and in polymetallic ore systems.
Antimony commonly occurs in minerals such as stibnite rather than as native bulk metal. The Geography Explorer keeps natural occurrence separate from resources, industrial production and recycling, because those datasets answer different questions about antimony.
Key point: Natural occurrence, resources, production and recycling are different geography questions.
What is antimony’s symbol?
Short answer: Sb.
The symbol Sb is the standardized chemical abbreviation for element 51. In a chemical formula, Sb identifies antimony atoms; a compound containing Sb is not automatically the same material as elemental antimony.
Key point: Sb always identifies element 51.
What is antimony’s atomic number?
Short answer: 51.
Atomic number is defined by proton count, so 51 protons are what make an atom antimony. A neutral antimony atom also has 51 electrons, while isotopes can have different neutron counts without changing the element.
Key point: Atomic number = proton count.
Scientific sources for Antimony
- Royal Society of Chemistry - Antimony
- Los Alamos National Laboratory - Antimony
- USGS - Mineral Commodity Summaries 2026
Questions to ask next about Antimony
A good element lesson should lead to the next useful question, not end after a list of facts.
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