Home Categories Inorganic chemistry Boron
A1230412

Boron , 99.9%metalsbasis, particle size (D50) ≤20μm , 7440-42-8

Synonym(s):
;Boric acid solution;Boron

CAS NO.:7440-42-8

Empirical Formula: B

Molecular Weight: 10.81

MDL number: MFCD00134034

EINECS: 231-151-2

Pack Size Price Stock Quantity
1G RMB79.20 In Stock
5G RMB159.20 In Stock
25G RMB615.20 In Stock
100g RMB3972.80 In Stock
others     Enquire
Update time: 2022-07-08

PRODUCT Properties

Melting point: 2300°C
Boiling point: 2550°C
Density  2.34 g/mL at 25 °C (lit.)
storage temp.  no restrictions.
solubility  H2O: soluble
form  Powder
color  Brown or dark
Specific Gravity 2.34~2.37
Resistivity 1.5E12 μΩ-cm, 20 °C
Water Solubility  insoluble H2O [MER06]
Crystal Structure Trigonal (rhombohedral) a = 1017 pm α = 65°12' hR105, R3m, β-B type
Merck  13,1333
Exposure limits ACGIH: TWA 2 mg/m3; STEL 6 mg/m3
Stability: Stable. Substances to be avoided include strong oxidizing agents and strong acids. May decompose on exposure to air - store under nitrogen. Highly flammable.
InChIKey UORVGPXVDQYIDP-UHFFFAOYSA-N

Description and Uses

Boron was discovered by Sir Humphry Davy and J.L. Gay-Lussac in 1808. It is a trivalent non-metallic element that occurs abundantly in the evaporite ores borax and ulexite. Boron is never found as a free element on Earth. Boron appears as charcoal-grey pieces or black powder or as crystalline; is a very hard, black material with a high melting point; and exists in many polymorphs.

Boron has several forms, and the most common one is amorphous boron, a dark powder, non-reactive to oxygen, water, acids, and alkalis. It reacts with metals to form borides. Boron is an essential plant micronutrient. Sodium borate is used in biochemical and chemical laboratories to make buffers. Boric acid is produced mainly from borate minerals by the reaction with sulphuric acid. Boric acid is an important compound used in textile products. The most economically important compound of boron is sodium tetraborate decahydrate or borax, used for insulating fibreglass and sodium perborate bleach. Compounds of boron are used in organic synthesis, in the manufacture of a particular type of glasses, and as wood preservatives. Boron filaments are used for advanced aerospace structures, due to their high strength and light weight.

As early as 1959, boron filaments were introduced as the first of a family of high-strength, high-modulus, low-density reinforcements developed for advanced aerospace applications. A process was engineered by Avco Specialty Materials (Lowell, Massachusetts) and the U.S. Air Force to manufacture boron filaments that had high strength and high stiffness, but low density and, hence, low weight. During the interim, advanced boron fibers have been used as a reinforcement in resin-matrix composites. Boron aluminum has been used for tube-shaped truss members, for reinforcing space vehicle structures, and has also been considered as a fan blade material for turbofan jet engines.These shortcomings led to the development of silicon-carbide (SiC) fibers for some applications.
The principal use of boron filaments is in the form of continuous boronepoxy pre-impregnated tape, commonly known as prepreg. Usually, the resin content is about 30–35% (weight). Boron composites have been used in military aircraft, including helicopters. In addition to aircraft, boron-epoxy composites have been used in tennis, racquetball, squash, and badminton rackets, fishing rods, skis, and golf club shafts, for improving strength and stiffness.
Boron has been used in cutting and grinding tools. Boron is 30–40% harder than silicon carbide and almost twice as hard as tungsten carbide. Boron also has interesting microwave polarization properties. Research (Southern Illinois University) has shown that a single ply of boron epoxy will transmit 98.5% and reflect 0.6% of the incident microwave power when the angle between the grain and the E-field is 90°. This property has been useful in the design of spacecraft antennas and radomes.

Safety

Symbol(GHS) 
GHS07
Signal word  Warning
Hazard statements  H302-H412
Precautionary statements  P264-P270-P273-P301+P312-P501
Hazard Codes  Xn,F
Risk Statements  22-11-63-62
Safety Statements  16-24/25-45-36/37/39-27-26
RIDADR  UN 3178 4.1/PG 2
WGK Germany  -
RTECS  ED7350000
TSCA  Yes
HazardClass  4.1
PackingGroup  III
HS Code  28045000

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