Magnesium links lightweight engineering to photosynthesis. Its metal is used in alloys and burns with an intense light, while magnesium sits at the center of chlorophyll molecules. Magnesium compounds also supply heat-resistant furnace materials, illustrating how bonding changes the roles available to one element.
FROM ELEMENT TO APPLICATION
AN ELEMENT IN CONTEXT
Why is low density only one requirement for a magnesium-alloy component?
Magnesium-containing metallic alloys
FOLLOW THIS RELATIONSHIP
Set the mechanical task
A transport component must carry particular loads with suitable stiffness and durability; reducing mass is useful only if those requirements remain satisfied.
Explore the model (optional)
MgFORM → INTERACTION → CONSEQUENCE
Follow the explanation in either direction. These are authored steps, not a physical clock.
Atomic identity, reference properties and structure models
INTERACTIVE 3D12 visible sites
An electron censusDrag to rotate · scroll or pinch to zoom
[Ne] 3s2. Grouping electrons by principal shell connects the neutral-atom configuration to periodic-table patterns.
What this representation means
A three-dimensional counting diagram. Dots are count markers, not measured electron positions; spherical placement and spacing are arbitrary. There are no electron trajectories here. Orbitals describe quantum states.
Magnesia and lime once belonged to an ill-defined family of materials. Joseph Black showed in 1755 that they represented different substances, helping establish magnesium's identity through its compounds. Obtaining the metal was a separate challenge: Davy prepared a small sample in 1808, and Antoine Bussy produced a larger sample in 1831. Recognition, isolation, and practical preparation therefore mark different stages of this history.
1755
Compounds distinguished
Black differentiated magnesia from lime through chemical investigation.
1831
Larger metal sample prepared
Bussy prepared magnesium in an amount that made its metallic properties easier to investigate.
Magnesium occurs in minerals such as magnesite and dolomite and in dissolved salts in seawater and other brines. These sources contain magnesium in compounds. Living systems also incorporate the element: a magnesium sits within chlorophyll, connecting mineral and aqueous chemistry with the molecular machinery of photosynthesis.
Magnesium metal combines low density with a tendency to react, and burning metal produces an intense white light. Its compounds can behave quite differently: magnesium withstands high temperatures. The same element can therefore appear in a combustible metal, a refractory ceramic, or a biological molecule.
Each section links its supporting references. Descriptions and diagrams were authored for this atlas. Source checks completed. Source checks dated 2026-09-06.
CITE THIS PAGE
Family labels and the group-3 layout are teaching conventions. A table position does not establish an unknown bulk property. Electronic configurations refer to neutral atoms; ions and material environments require their own account.
Read each reference property together with its units, conditions and the reference information below.
Not yet recorded: electron affinity, second ionization energy, ground-state term symbol, van der waals radius, thermal conductivity, specific heat capacity, electrical resistivity, crystal structure, lattice parameter a, space group, abundance in seawater, abundance in the universe, annual production, supply-risk listing, hazard classification, biological role, cas registry number, pubchem cid, wikidata item. These families are declared and awaiting an ingestion run against the source each names; they are listed here rather than shown as empty rows.
Physical
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Phase at 20 °C
solid
293.15 K, 101.325 kPa
Melting point in K
923 K
at standard pressure unless noted
Boiling point in K
1363 K
101.325 kPa
Density in g/cm³
1.74 g/cm³
solids and liquids at 293 K; gases at 273 K and 101.325 kPa
Atomic and electronic
Intended reference: Pauling electronegativity scale · Widely tabulated; original in The Nature of the Chemical Bond
Electronegativity in Pauling
1.31 Pauling
Pauling scale
First ionization energy in kJ/mol
737.7 kJ/mol
gas-phase neutral atom, ground state
Covalent radius in pm
141 pm
single-bond covalent radius
Common oxidation states
+2
states met in ordinary compounds; not exhaustive
Occurrence and identity
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Abundance in the crust in mg/kg
23300 mg/kg
upper continental crust, mass fraction
Has stable isotopes
Yesderived
Discovery year in CE
1755 CEderived
WHERE IT SITS AMONG ITS NEIGHBORS
Electronegativity across period 3
Mg 1.31 Pauling · Magnesium
Electronegativity across period 3. Exact values.
Na
0.93
Mg
1.31
Al
1.61
Si
1.9
P
2.19
S
2.58
Cl
3.16
Electronegativity down group 2
Mg 1.31 Pauling · Magnesium
Electronegativity down group 2. Exact values.
Be
1.57
Mg
1.31
Ca
1
Sr
0.95
Ba
0.89
Ra
0.9
The trend uses the same reference-property values as the periodic table. Elements with no recorded value are left out of the line rather than drawn at zero.
