Periodic Table

Gallium

Post Transition Metal

Quick Facts about Gallium

Zn
  • solid- state of matter at room temperature
  • Stable- has at least one stable isotope
  • +3- common oxidation states in compounds
  • ORC- crystal structure, atomic arrangement in solid form
Ge

Gallium (Ga) is element 31 on the periodic table. Atomic mass of Ga: 69.7230 u. Ga is in period 4, group 13. Melting point of Ga: 302.91 K.Density of Ga: 5.91 g/cm³.

Why Gallium Matters

Gallium in everyday life and industry

In Your Home

  • Gallium arsenide semiconductors power smartphones and solar cells
  • Gallium's low melting point (29.76°C) makes it melt in your hand

Industry Uses

MedicalMedical thermometers now use gallium alloys instead of mercury
IndustryLEDs and laser diodes rely on gallium compounds

In Your Body

✗ Not essential

Gallium has no known biological role. Gallium-67 is used in medical imaging for cancer and infection. Gallium citrate can fight certain antibiotic-resistant bacteria.

Safety: The metal is considered relatively non-toxic.

Discovery of Gallium

Discovered by Paul Émile Lecoq de Boisbaudran in France, 1875

Name origin: Latin: Gallia (France).

History & Events

1875
Named after 'Gallia,' the Latin name for France
1875
Discovered in 1875 by French chemist Lecoq de Boisbaudran
1875
Predicted by Mendeleev as 'eka-aluminum' before discovery
1875
First element discovered that validated Mendeleev's periodic table predictions

About Gallium

Soft silvery metallic element, belongs to group 13 of the periodic table. The two stable isotopes are Ga-69 and Ga-71. Eight radioactive isotopes are known, all having short half-lives. Gallium Arsenide is used as a semiconductor. Corrodes most other metals by diffusing into their lattice. First identified by Francois Lecoq de Boisbaudran in 1875.

Atomic Properties of Ga

Atomic Number of Ga
31
Atomic Mass of Ga
69.7230 u
Electron Configuration
[Ar] 3d10 4s2 4p1
Electronegativity
1.81
Block
p-block
Group
13
Period
4

Physical Properties of Ga

Phase (STP)
solid
Melting Point of Ga
302.91 K
Boiling Point of Ga
2673.00 K
Density of Ga
5.9100 g/cm3

Thermal Properties

Heat of Fusion
5.59 kJ/mol
Heat of Vaporization
270.30 kJ/mol
Specific Heat
0.37 J/g·K
Molar Heat Capacity
26.03 J/mol·K
Thermal Conductivity
28.10 W/m·K

Atomic Radii

Calculated
130 pm
Covalent
124 pm
Van der Waals
187 pm
Metallic
125 pm

Common Misconceptions

Wrong:Gallium will poison you if you hold it.
Correct:Gallium won't poison you if you hold it, despite melting in your hand
Wrong:Gallium is harmless to other metals.
Correct:Gallium attacks aluminum and other metals, diffusing into their crystal structure and causing them to become brittle and crumble
Wrong:Lecoq de Boisbaudran named gallium after himself (Le Coq = rooster = gallus in Latin).
Correct:He named it after Gallia (France), though the coincidence with his name (gallus = rooster) is often noted

Isotopes of Gallium

Gallium has 2 naturally occurring isotopes, plus 2 notable radioactive isotopes.

IsotopeAtomic Mass (u)AbundanceHalf-LifeDecay Mode
6731Ga (Ga-67)Gallium-67 isotope66.92820170%3.26 daysEC
6831Ga (Ga-68)Gallium-68 isotope67.92798010%67.7 minutesβ⁺, EC
6931Ga (Ga-69)Gallium-69 isotope68.925573560.11%
7131Ga (Ga-71)Gallium-71 isotope70.9247025839.89%

Data source: NIH PubChem (aggregated from IUPAC, NIST)

Isotope Applications

Isotopes of Gallium have important real-world applications in science and industry.

Medical Applications

68Ga (with a half-life of 68 min) is a radioactive isotope that emits positrons, which are used to produce high-resolution imaging with positron emission tomography (PET). Unlike 18F, which is most commonly used, 68Ga is more easily produced using a cost-effective generator with the parent radionuclide 68Ge (with a half-life of 271 days) (Fig. IUPAC.31.1). Once produced, 68Ga easily couples to biomolecules (most commonly peptides) that target G-protein coupled receptors, which are over-expressed on human tumor cells. The labeled protein acts as a radioactive tracer for cancer diagnostics. PET images are often coupled with CT images to get a more complete picture of the body [256], [257], [258], [259], [260], [261], [262]. Radiopharmaceutical 67Ga (with a half-life of 78 h) is a gamma-emitting isotope used in scintigraphy for medical imaging [263], [264], [265].

Abundance

Earth's Crust
19.0 mg/kg
Seawater
3.00×10-5 mg/L

Uses

Used in semiconductor production. It us used in making LEDs (light-emitting diodes) and GaAs laser diodes.

Sources

Found throughout the crust in minerals like bauxite, germanite and coal.

Geochemistry

Goldschmidt
chalcophile

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