二肖四码最准最厉害
二肖四码最准最厉害 二肖四码最准最厉害

B

Boron is a chemical element with atomic number 5 and the chemical symbol B. Boron is a trivalent nonmetallic element which occurs abundantly in the evaporite ores borax and ulexite. Boron is never found as a free element in nature.

Several allotropes of boron exist; amorphous boron is a brown powder, though crystalline boron is black, hard (9.3 on Mohs' scale), and a weak conductor at room temperature. Elemental boron is used as a dopant in the semiconductor industry, while boron compounds play important roles as light structural materials, nontoxic insecticides and preservatives, and reagents for chemical synthesis.

Boron is an essential plant nutrient, although higher soil concentrations of boron may also be toxic to plants. As an ultratrace element, boron is necessary for the optimal health of rats and presumably other mammals, though its physiological role in animals is poorly understood.

TECHNICAL DATA
SymbolBDenSity/gcm-3 (β rhombohedral)2.35
Atomic number5(α rhombohedral)2.45
No. of naturally occurring isotopes2Melting point /°C (β rhombohedral)2180
Atomic weight10.81Boiling point /°C (β rhombohedral)~3650
Electronic configuration[He] 2s22p1ΔHsub/kJmol-1570
Ionization energy/kJmol -1800.5Electronegativity χ2
II2426.5Electrical conductivity
III3658.7(25°C)/ohm-1 cm-1l.5x 10-6
EVAPORATION TECHNIQUES
Temperature (oC) @Vap. PressureTechniquesRemarks
10-8 Torr10-6 Torr10-4 TorrElectron BeamCrucibleCoilBoat
1278 Sublimes1548 Sublimes1797 SublimesExcellentGraphite & Vitreous Graphite-GraphiteMaterial explodes with rapid cooling. Forms carbide with container.



B
Sputtering Targets
Matierial SymbolAtomic Number     Thermal Conductivity         Theoretical Density 
W/m.K           g/cc
Boron_BB5272.37



Below is the periodic table of chemical elements.The elements in red are the ones Nexteck's product contain. Click them, you will come to the details.

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二肖四码最准最厉害

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