Catalog Number
ACMA00014304
Description
DryPowder; OtherSolid
Molecular Weight
10.81g/mol
InChI Key
ZOXJGFHDIHLPTG-UHFFFAOYSA-N
Density
Amorphous, 2.350 g/cu cm; alpha-rhombohedral, 2.46 g/cu cm; alpha-tetragonal, 2.31 g/cu cm; beta-rhombohedral, 2.35 g/cu cm
Solubility
Insoluble in water; unaffected by aqueous hydrochloric and hydrofluoric acids; when finely divided it is soluble in boiling nitric and sulfuric acids and in molten metals such as copper, iron, magnesium, aluminum, calcium; reacts vigorously with fused sodium peroxide or with a fusion mixture of sodium carbonate or potassium nitrate;Soluble in concentrated nitric and sulfuric acids; insoluble in water, alcohol, ether
Color/Form
Polymorphic: alpha-rhombohedral form, clear red crystals; beta-rhombohedral form, black; alpha-tetragonal form, black, opaque crystals with metallic luster; amorphous form, black or dark brown powder; other crystal forms are known but not entirely characterized;Filaments, powder, whiskers, single crystals
Covalently-Bonded Unit Count
1
MeSH Entry Terms
Boron;Boron 11;Boron-11
Monoisotopic Mass
11.009305g/mol
Other Experimental
Atomic number 5; naturally-occurring isotopes: 10,11; three short-lived artificial isotopes: 8,12, 13;Alpha-rhombohedral form, 12 atoms/unit cell; beta-rhombohedral form, 105 atoms/unit cell; alpha-tetragonal form, 50 atoms/unit cell;The alpha-rhombohedral form of boron is the simplest crystal structure with slightly deformed cubic close packing, which degrades at 1200 °C and at 1500 it converts to beta-rhombohedral boron, which is the most thermodynamically stable form.;Crystalline boron is very inert. Low purity, higher temperature, and changes in or lack of crystallinity all increase the chemical reactivity.;Boron exists naturally as (10)B (19.9%) and (11)B (80.1%); ten other isotopes of boron are known;Amorphous form, heat capacity: 2.858 cal/g-atom/deg C at 25 °C; beta-rhombohedral form, heat capacity: 2.650 cal/g-atom/deg C at 25 °C;Feeble conductor of electricity at room temperature, good conductor at high temperature; self limiting reaction with oxygen due to formation of boric oxide film; oxide coating evaporates above 1000 °C; crystals are almost as hard as diamond; reacts with fluorine at room temperature;Energy band gap of 1.50-1.56 eV; transmits portions of the infrared;High neutron absorption capacity; amphoteric; Mohs hardness, 9.3
Stability
Fairly stable at normal temperature.
Vapor Pressure
1.56X10-5 atm (0.0119 mm Hg) at 2140 °C
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