General Description
Odorless white solid. Sinks in water.
Reactivity Profile
BERYLLIUM OXIDE(1304-56-9) is incompatible with the following: Acids, caustics, chlorinated hydrocarbons, oxidizers, molten lithium, magnesium .
Air & Water Reactions
The amount of heat generated by hydrolysis may be large.
Hazard
Highly toxic by inhalation. Keep container
tightly closed and flush out after use.
Health Hazard
Any dramatic, unexplained weight loss should be considered as possible first indication of beryllium disease. Other symptoms include anorexia, fatigue, weakness, malaise. Inhalation causes pneumonitis, nasopharyngitis, tracheobronchitis, dyspnea, chronic cough. Contact with dust causes conjunctival inflammation of eyes and irritation of skin.
Fire Hazard
Special Hazards of Combustion Products: Toxic beryllium oxide fume may form in fire.
Description
Beryllium oxide
(BeO) is formed by the ignition of beryllium metal in an oxygen atmosphere. The resulting solid is colourless
and insoluble in water.
Physical properties
Beryllium oxide (BeO) is a white crystalline oxide. It occurs in nature as the mineral “Bromellite”. Historically, beryllium oxide was called glucina or glucinium oxide. It is an electrical insulator and its thermal conductivity is such that it is higher than any other nonmetal except diamond, and actually exceeds that of some metals. Its high melting point leads to its use as a refractory.
Definition
ChEBI: A beryllium molecular entity consisting of beryllium (+2 oxidation state) and oxide in the ratio 1:1. In the solid state, BeO adopts the hexagonal wurtzite structure form while in the vapour phase, it is present as discrete diatomic covalent molecules.
Preparation
Beryllium oxide can be prepared by calcining beryllium carbonate, dehydrating the hydroxide or igniting the metal with oxygen gas, as shown in the following reactions:
BeCO3→BeO＋CO2
Be(OH)2→BeO＋H2O
2Be＋O2→2BeO
Igniting beryllium in air
Production Methods
Single crystals are grown by hydrothermal synthesis using Beryllium oxide and NaOH solution, but the size smaller than 0.6 mm is only obtained. The pressed plate (thickness of 0.3–1.0 mm) has the density of 99.5% of a single crystal and has the transmittance almost same as the single crystal.
Industrial uses
A colorless to white crystalline powder of the composition beryllium oxide, also called beryllia. It has a specific gravity of 3.025, a high melting point, about 2585 C, and a Knoop hardness of 2000. It is used for polishing hard metals and for making hot-pressed ceramic parts. Its high heat resistance and thermal conductivity make it useful for crucibles, and its high dielectric strength makes it suitable for high-frequency insulators. Single-crystal beryllia fibers, or whiskers, have a tensile strength above 6800 MPa.
Beryllium oxide is tapped for nuclear reactor service because of its refractoriness, high thermal conductivity, and ability to moderate (slow down) fast neutrons. The thermal neutrons that result are more efficient in causing fusion of uranium- 235. Nuclear industry uses for beryllia include reflectors and the matrix material for fuel elements. When mixed with suitable nuclear poisons, beryllium oxide may be a new candidate for shielding and control rod assembly applications.
Safety Profile
Confirmed carcinogen withexperimental tumorigenic data. Experimental teratogenicdata. Other experimental reproductive effects. Incompatible with (Mg +heat). When heated to decomposition it emits very toxicfumes of BeO.
Structure and conformation
The space lattice of Beryllium oxide belongs to the hexagonal system with lattice constants a=0.2698 nm and c=0.4380 nm.
