Write the formula for gallium arsenide, the solar-cell semiconductor.
Formally Ga3+ pairs with arsenide As3-, one-to-one: GaAs. In reality the bonding is covalent, but the 3+/3- bookkeeping predicts the correct 1:1 formula.
What Is the Charge of Gallium?
Gallium commonly forms Ga3+ in introductory ionic compounds.
Gallium forms Ga3+ in its common compounds — Ga2O3, GaCl3, and gallium nitride (GaN), the semiconductor behind blue LEDs and fast phone chargers. A +1 state exists at high temperatures but never survives ordinary conditions.
| Element | Gallium |
|---|---|
| Symbol | Ga |
| Atomic number | 31 |
| Common ionic charge | +3 |
| Common ions | Ga3+ |
Visual reference
Gallium element image and atomic model
Images are used as visual references; charge rules still depend on the compound.
How Gallium's outer electrons decide its charge
Gallium sits below aluminum with [Ar]3d10 4s2 4p1. The same three-electron giveaway that fixes aluminum at 3+ applies here; the filled 3d10 shell underneath stays sealed. The heavier members of this group (indium, thallium) start favoring +1, but gallium is still firmly a 3+ element.
The Gallium mistake worth a warning
Assuming gallium's famous melting-in-your-hand trick (29.8 °C) relates to its ionic behavior. Melting is a metallic-bonding property of neutral gallium; its ions in compounds are ordinary, stable Ga3+.
Worked example: Ga in a formula problem
Ga3+ in real compounds
GaCl3
Gallium chloride
Ga3+ balances chloride ions.
Ga2O3
Gallium oxide
Gallium can form oxides where total positive and negative charge balances.
Questions students ask about gallium
What charge is gallium in blue LEDs?
In GaN, gallium is formally +3 and nitrogen -3. The 2014 Nobel Prize in Physics went to making this exact compound emit blue light efficiently.
Why does gallium 'wet' and destroy aluminum?
Neutral gallium atoms diffuse along aluminum's grain boundaries and break the metal's cohesion — an infamous demonstration. It is metal-metal mischief, not ion chemistry; no charges change.
Does gallium follow the same charge as boron above it?
In numbers yes (+3), in nature no: boron's +3 is purely covalent bookkeeping, while gallium genuinely forms Ga3+ salts that dissolve in water, like Ga(NO3)3 used in medical imaging.
How do I use this charge in formulas?
Combine positive and negative ions so the total charge is zero — or let the ionic compound calculator do the crossing for you. The full chart lives on the periodic table with charges.
Where this data comes from
Charges and element facts on this page are checked against the primary references below. Found an error? Email hello@periodictablewithcharges.com — corrections ship in the next content update. See how this site is edited.