Atomic / phase data
Reference values are evaluated.
B12 motif
The icosahedral motif represents important crystalline allotropes, not a complete beta-boron unit cell.
Isotopes
10B/11B natural-isotope context is established.
Geography
Borate commodity context is kept distinct from elemental structure.
The lens describes evidence status, not confidence theatre. “Unknown” is kept unknown, and teaching schematics are not presented as direct measurements.
Boron (B)
Boron is element 5, a metalloid whose electron-deficient bonding produces unusual clusters and network solids. The B₁₂ icosahedron, borates, borosilicate glass and two stable isotopes make it far more than a simple Period 2 tile.
Boron atomic number, mass, electron configuration and key properties
Boron: quick answers
How many protons, neutrons and electrons does boron have?
Boron’s atomic number is 5, so every boron atom has 5 protons, and a neutral atom also has 5 electrons. Its most common natural isotope, boron-11, has 6 neutrons (other isotopes have different neutron counts).
What is the symbol for boron?
The chemical symbol for boron is B.
Is boron a solid, liquid or gas at room temperature?
Boron is a solid at room temperature (about 25 °C).
What family (group) is boron in?
Boron is a metalloid, in group 13, period 2 of the periodic table.
How many valence electrons does boron have?
Boron has 3 valence electrons, the electrons in its outer shell, which matches its position in group 13.
What is the electron configuration of boron?
The ground-state electron configuration of boron is [He] 2s² 2p¹.
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.
5 protons define boron.
The ground-state configuration provides the starting point for its chemistry.
Periodic position organizes recurring chemistry and trends.
The teaching nucleus is one isotope, not the relative atomic mass.
Phase boundaries are condition-dependent and evidence-labelled.
Boron in its period and family
Boron begins Group 13 in Period 2. Unlike the heavier metallic members of the group, elemental boron is a hard covalent-network metalloid.
Boron Visual Lab
Inspect the 2p orbital, build a B₁₂ icosahedral motif, compare atomic boron with borate chemistry, and connect bonding to borosilicate glass, boron carbide, neutron absorption and plant nutrition.
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.
Boron in one minute
Atomic number 5 means 5 protons.
Neutral boron has three valence electrons: 2s²2p¹.
Boron is classified as a metalloid.
Important crystalline boron allotropes use B₁₂ icosahedral motifs.
Natural boron is mainly ¹⁰B and ¹¹B, whose neutron interactions make isotope composition technologically important.
Shell rings organize electron counts. They are not electron trajectories or orbital shapes.
2 · 3 electrons
The atomic 2p cloud is an isolated-atom probability model. Solid boron is a many-centre bonded network and cannot be interpreted as a collection of fixed atomic p-orbital “lobes.”
The viewer emphasizes a B₁₂ icosahedral building motif characteristic of important crystalline boron allotropes. It is a teaching motif, not a complete beta-rhombohedral unit cell.. 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 atomic 2p cloud is an isolated-atom probability model. Solid boron is a many-centre bonded network and cannot be interpreted as a collection of fixed atomic p-orbital “lobes.”
Where do I meet boron?
Clickable learning cards connect the element to materials, environment, technology, biology or research - depending on what the evidence actually supports.
Borosilicate glass
Boron oxide in glass formulations helps produce useful thermal and chemical properties.
From B atom to B₁₂ icosahedral network
Boron’s three valence electrons lead to electron-deficient multicentre bonding rather than simple metallic or ionic structures.
2s²2p¹ valence
The isolated atom has three valence electrons.
Boron, aluminium and gallium
Compare nearby elements to see which patterns repeat and which properties remain element-specific.
| Class | Metalloid |
|---|---|
| Valence | 2s²2p¹ |
| Class | Metal |
|---|---|
| Valence | 3s²3p¹ |
| Class | Metal |
|---|---|
| Valence | 4s²4p¹ |
Boron 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 | 5 | Source-reviewed; see Sources below | Evaluated |
| Relative atomic mass | 10.81 | Source-reviewed; see Sources below | Evaluated |
| Ground-state electron configuration | [He] 2s² 2p¹ | Source-reviewed; see Sources below | Evaluated |
| Group / period / block | Group 13 · Period 2 · p-block | Periodic-table placement | Evaluated |
| Electronegativity | 2.04 | Source-reviewed; see Sources below | Evaluated |
| Reference isotope | ¹¹B | Source-reviewed; see Sources below | Evaluated |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| State context | Hard dark solid at 20 °C | Source-reviewed; see Sources below | Evaluated |
| Density | 2.34 g/cm³ | Source-reviewed; see Sources below | Evaluated |
| Material / molecular structure | Boron · B₁₂ icosahedral motif in rhombohedral allotropes | The viewer emphasizes a B₁₂ icosahedral building motif characteristic of important crystalline boron allotropes. It is a teaching motif, not a complete beta-rhombohedral unit cell. | Measured |
| Classification | Metalloid | Periodic-table / chemistry classification | Evaluated |
| Structure-model scope | The viewer emphasizes a B₁₂ icosahedral building motif characteristic of important crystalline boron allotropes. It is a teaching motif, not a complete beta-rhombohedral unit cell. | Teaching visualization; exact crystallographic coordinates are not implied unless stated. | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Melting / transition reference | 2350 K | Source-reviewed; see Sources below | Evaluated |
| Boiling / gas reference | 4273 K | Source-reviewed; see Sources below | Evaluated |
| Phase-path context | The simple temperature track uses evaluated bulk melting and boiling references, while the Structure panel separately explains allotropes and B₁₂ motifs. Exact transformation behavior among solid allotropes depends on conditions and is not reduced to an invented single marker. | 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 | +3 | Source-reviewed; see Sources below | Evaluated |
| Ion / common ion context | Covalent / borate chemistry; simple B³⁺ is not the ordinary picture | Source-reviewed; see Sources below | Evaluated |
| Periodic chemistry context | Boron begins Group 13 in Period 2. Unlike the heavier metallic members of the group, elemental boron is a hard covalent-network metalloid. | Element-specific interpretation | Reviewed |
| Chemistry caution | Elemental form, ions and compounds are distinct chemical objects. | Interpretive teaching rule | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| ¹¹B | Stable · major natural isotope | Reference teaching nucleus: 5 protons and 6 neutrons. | Evaluated |
| ¹⁰B | Stable · minor but technologically important | Its strong neutron-capture behavior underlies several nuclear and detector applications. | Evaluated |
| Natural boron | Two stable-isotope mixture | The relative atomic mass reflects the natural mixture of ¹⁰B and ¹¹B. | Evaluated |
| Teaching nucleus | ¹¹B · 5 protons + 6 neutrons | Reference isotope used in the nucleus model | Reviewed |
| Property | Value | Context / provenance | Evidence |
|---|---|---|---|
| Page evidence note | Atomic and ordinary physical values are evaluated. The B₁₂ viewer is a reviewed structural motif, not a claim that all boron solids have one simple molecular structure. Commodity geography is kept distinct from bonding/allotrope science. | Evidence summary for this guide | Reviewed |
| Structure evidence | The viewer emphasizes a B₁₂ icosahedral building motif characteristic of important crystalline boron allotropes. It is a teaching motif, not a complete beta-rhombohedral unit cell. | 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 Boron a solid, liquid or gas? State at temperature
The simple temperature track uses evaluated bulk melting and boiling references, while the Structure panel separately explains allotropes and B₁₂ motifs. Exact transformation behavior among solid allotropes depends on conditions and is not reduced to an invented single marker.
Where on Earth is Boron found or produced?
Who discovered Boron, and when?
Joseph Louis Gay-Lussac and Louis Jacques Thénard, and independently Humphry Davy, produced impure boron.
Better purification revealed boron’s unusual hard, covalent solid forms.
Borosilicate glass, boron carbide, borates and isotope applications expanded boron’s industrial importance.
Boron chemistry spans glass, ceramics, detergents, agriculture, semiconductors and neutron technology.
From borate minerals to useful boron materials: high-level context
Boron is concentrated in borate minerals formed in particular evaporitic and volcanic-geothermal settings.
Mining and beneficiation produce borate feeds; geology and annual production should be treated as dated datasets.
Chemical conversion yields boric acid, borates, boron oxide and other intermediates for glass, ceramics and specialty chemistry.
Elemental or high-purity boron production requires specialized industrial processes that are outside this educational overview.
What is boron used for?
Glass & ceramics
Borates and boron oxide are important in borosilicate glass, fiberglass and ceramic formulations.
Hard materials
Boron carbide and related boron-rich ceramics provide high hardness and low density.
Agriculture
Boron is an essential plant micronutrient supplied in controlled fertilizer forms.
Neutron technology
¹⁰B is useful for neutron absorption in selected detectors, shielding and control applications.
Boron isotopes and natural abundance
¹¹B
Stable · major natural isotopeReference teaching nucleus: 5 protons and 6 neutrons.
¹⁰B
Stable · minor but technologically importantIts strong neutron-capture behavior underlies several nuclear and detector applications.
Natural boron
Two stable-isotope mixtureThe relative atomic mass reflects the natural mixture of ¹⁰B and ¹¹B.
Five-question Boron check
Atomic number?
Classification?
Valence electrons?
Key structural motif?
Which isotope is notable for neutron capture?
Boron 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 boron’s atomic number?
Short answer: 5.
Atomic number is defined by proton count, so 5 protons are what make an atom boron. A neutral boron atom also has 5 electrons, while isotopes can have different neutron counts without changing the element.
Key point: Atomic number = proton count.
Is boron a metal?
Short answer: No. Boron is usually classified as a metalloid.
This guide classifies Boron as a metalloid. Its periodic position is Period 2, p-block, Group 13. Boron begins Group 13 in Period 2. Unlike the heavier metallic members of the group, elemental boron is a hard covalent-network metalloid.
Key point: Periodic-table classification describes recurring atomic/chemical behavior; it does not make every element in a column physically identical.
How many valence electrons does boron have?
Short answer: Three: 2s²2p¹.
The neutral-atom ground-state reference used on this page is [He] 2s² 2p¹. This is an isolated-atom reference: bonding and ion formation can change which outer electrons are present or chemically active. The listed common oxidation-state context is +3, which helps connect the atomic configuration to ordinary chemistry without treating electron counting as a single universal rule.
Key point: Electron configuration is a ground-state atomic reference, not a literal picture of every compound.
What is boron used for?
Short answer: Major uses include borosilicate glass and fiberglass, ceramics, agriculture and neutron-absorbing materials.
Glass & ceramics: Borates and boron oxide are important in borosilicate glass, fiberglass and ceramic formulations. Hard materials: Boron carbide and related boron-rich ceramics provide high hardness and low density. Boron is best understood through bonding: three valence electrons do not lead to a simple metal-like or ionic picture. Cluster and multicentre bonding help stabilize complex boron structures.
Key point: Always distinguish the pure element from the compound, alloy, isotope or device material that actually performs the application.
Why is boron’s structure unusual?
Short answer: Electron-deficient multicentre bonding supports cluster motifs such as B₁₂ icosahedra and complex network solids.
The viewer emphasizes a B₁₂ icosahedral building motif characteristic of important crystalline boron allotropes. It is a teaching motif, not a complete beta-rhombohedral unit cell. The Structure viewer is an evidence-aware teaching model: measured or defensible structures are shown as models, while genuinely unknown bulk structures remain explicitly unknown.
Key point: A teaching lattice is a scientific model, not a photograph of a finite chunk of material.
What is special about boron-10?
Short answer: ¹⁰B strongly absorbs neutrons, which makes it useful in selected detector and nuclear-technology contexts.
Neutron technology ¹⁰B is useful for neutron absorption in selected detectors, shielding and control applications. Borosilicate glass Boron oxide in glass formulations helps produce useful thermal and chemical properties.
Key point: Use the direct answer together with the material, isotope and evidence context shown elsewhere on the page.
Scientific sources for Boron
- Royal Society of Chemistry - Boron
- NIST - Atomic Data for Boron
- USGS - Mineral Commodity Summaries 2026
Questions to ask next about Boron
A good element lesson should lead to the next useful question, not end after a list of facts.
Found an error, something unclear, or a missing topic?
Tell us what you noticed. Feedback goes to a private review queue and is never published automatically.