Gallium is chemically similar to aluminum and slowly oxidizes in moist air until a protective film is formed. When it burns in air or oxygen, it forms the white oxide Ga2O3.
Galliumoxid | Ga2O3 – PubChem.
Indium metal is soluble in acids, but does not react with oxygen at room temperature. At higher temperatures, however, it combines with oxygen to form indium oxide.
Gallium expands by about 3% when it solidifies. The metal is relatively unreactive. Does not react with air or water at room temperature and is only slightly attacked by mineral acids; it slowly oxidizes to red-hot and reacts with water at high temperatures.
Strong oxidation of metallic Ga to gallium(III) oxide (Ga2O3) can be expected at ~850 °C  or above in air or oxygen. The same oxide can also be obtained by burning liquid gallium droplets in air or oxygen.
Gallium is amphoteric (meaning it reacts as either an acid or a base depending on the circumstances) and reacts with sodium and potassium hydroxide solutions to form gallate and hydrogen gas. The halogens attack him fiercely.
If taken orally: Indium is POSTLY UNSAFE when taken orally. Indium is considered toxic to many parts of the body. For Intravenous Administration: Indium is LIKELY SAFE when the prescription product containing Indium (In-111) Pentetreotide is administered intravenously by a healthcare professional.
The critical rare metals (RMs) and metalloids discussed in this section are niobium, tantalum, cobalt, indium, zirconium, gallium, and lithium. Most of these elements are mined in significant quantities to meet global demand.
Indium is found on planets orbiting blue stars and can be placed in a refiner to produce purified chromatic metal for use in crafting advanced technologies .
Gallium(I) oxide is a brown-black diamagnetic solid that is resistant to further oxidation in dry air. It starts to decompose when heated to temperatures above 500°C, with the rate of decomposition depending on the atmosphere (vacuum, inert gas, air).
Gallium is a rare element on Earth, found at 19 ppm in the continental crust, its abundance is comparable to that of lithium and lead. It does not occur in elemental form, only in combined form, mainly in aluminum, zinc or germanium ores.
Gallium is one of the four non-radioactive metals (along with cesium, rubidium, and mercury) that are known to be liquids at or near normal room temperature.
Gallium compounds are mildly toxic, they are not considered hazardous but should not be inhaled or ingested. We do not recommend eating elemental gallium, but if small amounts were accidentally ingested it would most likely not be harmful.
Pure gallium is not a harmful substance for humans. It has been touched many times for the simple pleasure of seeing it melted by the heat given off by a human hand. However, it has been known to stain hands.
It is well known that gallium arsenide readily reacts with gold and gold-based alloys, the materials most commonly used for solar cell contacts. 1-5 In the case of gold contacts, the reaction has been shown to consist primarily of the dissolution of gallium and arsenic into (or through) the contact metallization.