4 Be Beryllium 9.012
Alkaline earth metal s-block Period 2 Group 2

Beryllium

Be · Element 4 · Alkaline earth metal

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A stiff, feather-light metal that is transparent to X-rays and lethally toxic as dust.

State at 20°C Solid
Atomic mass 9.012 u
Electron configuration[He] 2s²
3Li All 118 5B

Structure

The beryllium atom

Not a diagram of dots on rings — a Monte-Carlo sample of the actual probability density |ψ|² for each occupied subshell. Drag to rotate. Blue and violet mark opposite signs of the wavefunction, which is what makes bonding possible.

Orbital cloud

Measured values

Property sheet

Every bar shows where beryllium sits among all 118 elements for that property.

Physical

Density 1.85 g/cm³ 15%
Melting point 1560 K 65%
Boiling point 2743 K 53%
Specific heat 1.825 J/g·K
Thermal conductivity 200 W/m·K 95%

Atomic

Atomic radius 112 pm 11%
Covalent radius 96 pm
Van der Waals radius 153 pm

Electronic

Electronegativity 1.57 48%
Ionisation energy 899.2 kJ/mol 80%
Electron affinity —

Occurrence

Abundance in crust 2.8 mg/kg 61%

Identity

SymbolBe
Atomic number4
Atomic mass9.012 u
CategoryAlkaline earth metal
Blocks
Crystal structurehexagonal close-packed
Oxidation states+2
Discovered1798
Discovered byLouis-Nicolas Vauquelin

Sources: IUPAC 2021 standard atomic weights · CRC Handbook of Chemistry and Physics · NIST. Values marked ~ are predicted rather than measured.

Same element, different neutrons

Isotopes of beryllium

All beryllium atoms have the same number of protons, 4, and differ only in their number of neutrons: those variants are its isotopes. The most common, Be-9, has 5 neutrons and makes up 100% of natural beryllium.

Isotopes of beryllium found in nature, with their share of the natural element, and well-known radioactive ones
ISOTOPE Neutrons Natural Abundance Half-life Decay Mode
Be-7 3 — 53.22 days ε
Be-9 most common 5 100% Stable —
Be-10 6 — 1.51 × 10⁶ yrs β⁻

Here the classroom shortcut, rounded atomic mass (9.012) minus atomic number, gives the same answer: 5.

Decay modes

ε
electron capture
β⁻
beta-minus decay

Data: IAEA Nuclear Data Section, LiveChart of Nuclides, ground-state evaluations, retrieved October 10, 2026. Abundance is the share of atoms in the natural element; a dash means the isotope has no standard natural abundance.

Size, to scale

How big is a beryllium atom?

Radius 112 pm — that is 0.112 nm, so about 4.46 million of them side by side would span a millimetre.

Thermal range

Solid, liquid, gas — and when

Beryllium is liquid over a 1183 K window, from 1560 K to 2743 K.

Where it sits

Position in the table

Beryllium sits in period 2, group 2. Everything in group 2 shares the same outer-electron count, which is why they behave so similarly.

Other alkaline earth metals

12Mg 20Ca 38Sr 56Ba 88Ra
All alkaline earth metals

The story

What beryllium is, and how we found it

Light, strong metal with high melting point. Toxic in powder form.

The discovery of beryllium

The Sweet Mystery Revealed

The discovery of beryllium reads like a detective story spanning two decades, involving brilliant chemists, toxic crystals, and a metal so elusive it earned the nickname "glucinium" (sweet one) before its true nature was revealed.

The French Connection (1798)

Louis-Nicolas Vauquelin, a French pharmacist and chemist, was analyzing emeralds and beryl crystals in his Paris laboratory when he made a startling discovery. These beautiful green and blue gems contained an unknown element that produced a characteristically sweet taste when dissolved - hence the name "glucinium" from the Greek word "glykys" (sweet).

Vauquelin was already famous for discovering chromium the previous year, but beryllium proved far more challenging. He could identify the element's presence through chemical analysis but couldn't isolate the pure metal. The sweet-tasting compounds he created were actually beryllium salts, which we now know are extremely toxic - fortunately, Vauquelin only tasted tiny amounts.

The German Breakthrough (1828)

The race to isolate pure beryllium captivated European chemists for over 30 years. The breakthrough came simultaneously from two brilliant German scientists working independently:

Friedrich Wöhler, famous for synthesizing urea and disproving the "vital force" theory, developed an ingenious method. He heated beryllium chloride with potassium metal in a platinum crucible, producing tiny silvery beads of pure beryllium. Meanwhile, Antoine Bussy in France used the same reaction of potassium with beryllium chloride.

Both men faced enormous challenges - beryllium required temperatures above 1,287°C to melt, and its oxide formed an impenetrable protective layer.

The Name Controversy

A fierce naming battle erupted between French and German chemists. The French insisted on "glucinium" (Gl), while Germans preferred "beryllium" (Be) after the mineral beryl. The controversy lasted until 1949 when the International Union of Pure and Applied Chemistry officially chose "beryllium" - though some French and Russian texts still used "glucinium" into the 1970s.

Industrial Development (1900s-1940s)

Beryllium remained a laboratory curiosity until Alfred Stock and Hans Goldschmidt developed the first commercially successful production process in Germany in 1921. The metal's properties - lighter than aluminum but stronger than steel - caught military attention during World War II. The Manhattan Project used beryllium as a neutron reflector in nuclear weapons, suddenly making this obscure element strategically critical.

Applications

What beryllium is used for

Aerospace & Defense Applications

Beryllium is the backbone of modern aerospace engineering, earning its nickname as the "space age metal." Its exceptional properties make it irreplaceable in critical applications where failure is not an option.

Spacecraft & Satellite Technology

NASA relies heavily on beryllium for the James Webb Space Telescope mirrors, where 18 hexagonal beryllium segments form the primary mirror. The metal's thermal stability ensures the mirrors maintain their precise shape in the large temperature variations of space (the primary mirror segments operate at about 34 to 55 K, roughly -239°C to -218°C). Boeing uses beryllium in satellite components because it maintains dimensional stability while being about 75% lighter than steel.

Military & Defense Systems

The F-22 Raptor and F-35 Lightning II fighter jets use beryllium in their guidance systems and radar components. Lockheed Martin incorporates beryllium copper alloys in missile guidance systems where electromagnetic interference must be minimized. The metal's transparency to X-rays makes it the standard window material for X-ray tubes and detectors, and its neutron-reflecting properties suit it to reactor reflectors.

Precision Manufacturing

Beryllium copper (BeCu) alloys containing 0.5-3% beryllium create the world's finest springs and electrical contacts. Companies like Materion Corporation manufacture BeCu components for:

  • Medical devices: MRI machines, CT scanners, and surgical instruments
  • Electronics: High-end audio equipment, smartphone components, and computer connectors
  • Automotive: Anti-lock brake sensors, airbag systems, and fuel injection components

Nuclear Applications

Beryllium serves as a neutron reflector and moderator in nuclear reactors. Its low neutron absorption cross-section makes it ideal for reflecting neutrons back into the reactor core, increasing efficiency. The metal is also used in neutron sources for oil well logging and materials testing.

Specialized Tooling

Non-sparking beryllium copper tools are essential in explosive environments like oil refineries, chemical plants, and mining operations. These tools prevent dangerous sparks that could ignite flammable gases or dust.

Electronics & Technology

  • High-end audio equipment: Beryllium dome tweeters in speakers by Focal, TAD, and Yamaha for superior sound reproduction
  • Smartphone components: Beryllium copper springs in iPhone and Samsung Galaxy charging ports and buttons
  • Computer connectors: Gold-plated beryllium copper contacts in USB ports, HDMI cables, and motherboard sockets
  • Precision instruments: Swiss watch components, medical device springs, and scientific measurement tools

Automotive Industry

  • Safety systems: Beryllium copper in airbag deployment sensors and anti-lock brake components
  • Performance vehicles: Formula 1 and NASCAR engines use BeCu valve seats and guides to pull heat from titanium valves
  • Electric vehicles: Tesla and other EV manufacturers use beryllium alloys in battery management systems

Aerospace Applications

  • Commercial aircraft: Boeing 787 and Airbus A350 use beryllium in avionics and navigation systems
  • Space missions: SpaceX Falcon 9, NASA Mars rovers, and International Space Station components
  • Satellites: GPS satellites, weather monitoring systems, and communication satellites

Industrial Equipment
  • Non-sparking tools: Wrenches, hammers, and screwdrivers for explosive environments
  • Welding equipment: Electrode holders and resistance welding electrodes
  • Oil & gas industry: Drilling equipment, valve components, and safety tools

Where it comes from

Natural occurrence

2.8 mg/kg of Earth's crust · more abundant than 61% of elements

Terrestrial Distribution

Beryllium is a rare and precious element with an abundance of only 2.8 parts per million in Earth's crust, though still far more common than silver or platinum. Despite its scarcity, beryllium plays a crucial role in both geological processes and cosmic events.

Primary Mineral Sources

The most important beryllium ore is beryl (Be₃Al₂Si₆O₁₈), which forms beautiful gemstones when pure:

  • Emerald: Beryl colored green by chromium, found in Colombia, Zambia, and Brazil
  • Aquamarine: Blue beryl from iron traces, mined in Brazil, Madagascar, and Pakistan
  • Morganite: Pink beryl colored by manganese, discovered in California and Madagascar
  • Heliodor: Golden beryl colored by ferric iron (Fe³⁺), found in Ukraine and Namibia

Other beryllium minerals include bertrandite (Be₄Si₂O₇(OH)₂), found primarily in Utah's Spor Mountain, and chrysoberyl (BeAl₂O₄), which includes the precious cat's eye and alexandrite gems.

Global Mining Operations

The United States dominates beryllium production, with Materion Corporation's mine in Utah producing about half of the world's beryllium (230 of about 430 tons in 2025, USGS). China operates smaller mines in Xinjiang province, while Kazakhstan and Mozambique have emerging operations. The Spor Mountain mine in Utah contains the world's largest known bertrandite deposits.

Cosmic Origins

Beryllium has a fascinating cosmic history. Unlike most elements, beryllium cannot be formed in stellar nucleosynthesis because it's destroyed at the high temperatures inside stars. Instead, beryllium-9 is created through cosmic ray spallation - when high-energy cosmic rays collide with carbon and oxygen nuclei in space, breaking them apart to form beryllium.

This process makes beryllium a "cosmological chronometer" - scientists can estimate the age of cosmic rays by measuring beryllium isotopes in meteorites and space samples.

Handling

Safety

Hazard Warning

Inhaled beryllium dust or fume can cause sensitization and chronic beryllium disease at very low exposures; the OSHA limit is 0.2 μg/m³ as an 8-hour average. Even microscopic amounts can cause severe, irreversible lung disease. Solid beryllium parts are hazardous mainly when machining, grinding, melting or other processing releases dust or fume.

Chronic Beryllium Disease (Berylliosis)

Chronic Beryllium Disease (CBD) is an incurable, progressive lung condition caused by inhaling beryllium particles. Symptoms can appear decades after exposure and include:

  • Progressive shortness of breath and chronic cough
  • Chest pain and severe fatigue
  • Weight loss and night sweats
  • Can progress to respiratory failure and death, especially if exposure continues, although progression varies between individuals

Depending on the workplace, studies have found the disease in about 1% to more than 10% of exposed workers, with some individuals being genetically predisposed. There is no cure; corticosteroids and other treatments can ease symptoms and slow progression.

OSHA Regulations & Exposure Limits

Permissible Exposure Limit (PEL): 0.2 μg/m³ (8-hour time-weighted average)

Short-term Exposure Limit: 2.0 μg/m³ (15-minute average)

Action Level: 0.1 μg/m³ (triggers medical surveillance)

Required Safety Measures

  • Engineering controls: HEPA-filtered ventilation, negative pressure work areas, enclosed processes
  • Personal Protective Equipment: Full-face air-purifying respirators (assigned protection factor 50), or a powered air-purifying respirator when the worker requests one, disposable protective clothing, nitrile gloves
  • Medical surveillance: Exams at least every two years with pulmonary function tests, beryllium lymphocyte proliferation tests every two years, and low-dose CT scans when the physician recommends them
  • Decontamination: Dedicated shower facilities, separate change areas, contaminated clothing disposal

Emergency Procedures

Inhalation: Remove to fresh air immediately, seek medical attention even without symptoms

Skin contact: Wash thoroughly with soap and water, remove contaminated clothing

Eye contact: Flush with water for 15+ minutes, seek immediate medical care

Ingestion: Do not induce vomiting, seek immediate medical attention

Safe Storage & Handling

Store in sealed, labeled containers in designated areas with restricted access. Never dry sweep beryllium-contaminated areas - use HEPA vacuum systems only. Dispose of as hazardous waste through licensed contractors.

Keep exploring

Use beryllium in the tools

Quick answers

Beryllium: common questions

What is beryllium?

Beryllium (symbol Be) is element 4 on the periodic table, an alkaline earth metal in period 2, group 2. A stiff, feather-light metal that is transparent to X-rays and lethally toxic as dust. At room temperature it is a solid.

What is the electron configuration of beryllium?

Beryllium's ground-state electron configuration is [He] 2s², giving 2 occupied shells with the distribution 2, 2.

What are the melting and boiling points of beryllium?

Beryllium melts at 1560 K (1286.9 °C) and boils at 2743 K (2469.9 °C).

What is the atomic mass of beryllium?

The standard atomic weight of beryllium is 9.012 u. That is a weighted average across its naturally occurring isotopes, which is why it is rarely a whole number.

How many neutrons does beryllium have?

The most common beryllium atom, Be-9, has 5 neutrons: its mass number, 9, minus its atomic number, 4. It makes up 100% of natural beryllium. The classroom shortcut, rounded atomic mass (9.012) minus atomic number, gives the same 5.

How dense is beryllium?

Beryllium has a density of 1.85 g/cm³. Water is 1.0 g/cm³, so a block of beryllium is about 1.9× heavier.

What is the electronegativity of beryllium?

Beryllium has a Pauling electronegativity of 1.57. The scale runs from 0.70 (francium, the least greedy for electrons) to 3.98 (fluorine, the most). Values in this middle band tend to form covalent rather than strongly ionic bonds.

Who discovered beryllium, and when?

Beryllium was discovered in 1798 by Louis-Nicolas Vauquelin. Origin of the name: from the gemstone beryl.

How common is beryllium on Earth?

Beryllium makes up about 2.8 mg/kg of the Earth's crust — uncommon, but not rare.

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