|Name, Symbol, Number||Gallium, Ga, 31|
|Chemical series||True metals|
|Group, Period, Block||13 (IIIA), 4 , p|
|Density, Hardness||5904 kg/m3, 1.5|
|Atomic weight||69.723 amu|
|Atomic radius (calc.)||130 (136)pm|
|Covalent radius||126 pm|
|van der Waals radius||187 pm|
|Electron configuration||[Ar]33d10 4s2 4p1|
|e- 's per energy level||2, 8, 18, 3|
|Oxidation states (Oxide)||3 (amphoteric)|
|State of matter||Solid|
|Melting point||302.91 K (85.57 °F)|
|Boiling point||2477 K (3999 °F)|
|Molar volume||11.80 ×1010-3 m3/mol|
|Heat of vaporization||258.7 kJ/mol|
|Heat of fusion||5.59 kJ/mol|
|Vapor pressure||9.31 E-36 Pa at 302.9 K|
|Speed of sound||2740 m/s at 293.15 K|
|Electronegativity||1.81 (Pauling scale)|
|Specific heat capacity||370 J/(kg*K)|
|Electrical conductivity||6.78 106/m ohm|
|Thermal conductivity||40.6 W/(m*K)|
|1st ionization potential||578.8 kJ/mol|
|2nd ionization potential||1979.3 kJ/mol|
|3rd ionization potential||2963 kJ/mol|
|4th ionization potential||6180 kJ/mol|
|Most Stable Isotopes|
|SI units & STP are used except where noted.|
|Table of contents|
5 External Links
Very-pure gallium has a stunning silvery color and its solid metal fractures conchoidally like glass. Gallium metal expands 3.1 percent when it solidifys and therefore shouldn't be stored in either glass or metal containers. Gallium also corrodes most other metals by diffusing into their metal lattice.
Gallium is one of four metals (with cesium, mercury, and rubidium) which are liquid at near normal room temperature and can therefore be used in high-temperature thermometers. It is also notable for having one of the largest liquid ranges for a metal and for having a low vapor pressure at high temperatures.
This metal has a strong tendency supercool below its melting point thus necessitating seeding in order to solidify. High-purity gallium is attacked slowly by mineral acids. The melting point temperature is very low, T=30 °C, and the density is higher in the liquid state than in the crystalline state (like in the case of water; the opposite effect is normally found for metals).
Ga does not crystallize in any of the simple crystal structures. The stable phase under normal conditions is orthorhombic with 8 atoms in the conventional unit cell. Each atom has only one nearest neighbor (at a distance of 2.44 Å) and six other neighbors within additional 0.39 Å. Many stable and metastable phases are found as function of temperature and pressure.
The bonding between the nearest neighbors is found to be of covalent character, hence Ga2 dimers is seen as the fundamental building block of the crystal. The compound, gallium arsenide can convert electricity directly into coherent light (this property is vital to light-emitting diodes).
Analog integrated circuits are the largest application for gallium, with optoelectronic devices (mostly laser diodes and light-emitting diodes) as the second largest end use. Other uses;
- Since it wets glass or porcelain, gallium is used to create brilliant mirrors.
- Used widely to dope semiconductors and produce solid-state devices like transistors.
- Gallium readily alloys with most metals, and has been used as a component in low-melting alloys.