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boron [B]
From the Arabic buraq, borax, its most important ore Pure form isolated in 1808 by British chemist Sir Humphrey Davy & independently by French chemists Joseph-Luis-Gay-Lussac & Louis-Jacques Thenard
Occurrence:
1) makes up 0.0003% of the earth's crust
2) never found its pure form in nature
3) occurs as orthoboric acid in certain volcanic spring waters
4) occurs in ores
a) rasorite (kernite)
b) borax (tincal)
Characteristics:
1) trivalent metalloid element
2) brown-black solid
3) crystalline boron is chemically inert
Uses:
1) metallurgy & nucleonics
2) to make borosilicate glass or Pyrex
3) in fission-reactor control rods to capture neutrons & regulate power produced
4) used with silicon in making p-type semiconductors
5) as an eye disinfectant
6) in pyrotechnics to make a green color
Pathology: (Toxicology)
1) excessive amounts are poisonous
2) once used in medicines
Laboratory:
- boron in specimen
- boron in hair
- boron in erythrocytes
- boron in tissue
- boron in body fluid
- boron in blood
- boron in serum/plasma
- boron in urine
Notes:
1) essential micronutrient for plants
2) foods rich in boron may provide protective effect against prostate cancer [3]
a) red wine
b) almonds
c) coffee
d) certain fruits & nuts
Related
borate
General
trace element
Properties
SIZE: AW = 10.81
atomic number
VALUE: 5
VALENCE: HE 2S2 2P2
References
- Webster's Ninth New Collegiate Dictionary, Miriam-
Webster Inc. Springfield, MA 1990
- Chemical & Engineering News, Sept 8, 2003
- Web MD, April 5, 2001