Chemical Name: Diborane
IUPAC NAME: Boranylidyneborane
CAS No.: 19287-45-7
EINECS: 242-940-6
Molecular Formula: B₂H₆
Molecular Weight: 27.65 g/mol
Melting Point: -165°C
Following is the structure of Diborane (19287-45-7):

Product Categories about Diborane (19287-45-7) are Inorganics ; BoranesChemical Synthesis ; Compressed and Liquefied GasesVapor Deposition Precursors ; Gases ; Precursors by Metal ; Reduction ; Synthetic Reagents
The chemical synonymous of Diborane (19287-45-7) are Boron hydride ; Diboranemixtures ; Diboron hexahydride ; Diboronhexahydride ; Dlborane

 Diborane (19287-45-7) was first synthesised in the 19th century by hydrolysis of metal borides, but it was never analysed. From 1912 to 1936, the major pioneer in the chemistry of boron hydrides, Alfred Stock, undertook his research that led to the methods for the synthesis and handling of the highly reactive, volatile, and often toxic boron hydrides. He proposed the first ethane-like structure of diborane.Electron diffraction measurements by S. H. Bauer initially appeared to support his proposed structure.Because of a personal communication with L. Pauling (who supported the ethane-like structure), H. I. Schlessinger did not specifically discuss 3-center-2-electron bonding in his then classic review in the early 1940s.The review does, however, discuss the C2v structure in some depth, "It is to be recognized that this formulation easily accounts for many of the chemical properties of diborane..."In 1943 an undergraduate student at Balliol College, Oxford, H. Christopher Longuet-Higgins, published the currently accepted structure together with R. P. Bell.This structure had already been described in 1921.The years following the Longuet-Higgins/Bell proposal witnessed a colorful discussion about the correct structure. The debate ended with the electron diffraction measurement in 1951 by K. Hedberg and V. Schomaker, with the confirmation of the structure shown in the schemes on this page.William Nunn Lipscomb, Jr. further confirmed the molecular structure of boranes using X-ray crystallography in the 1950s, and developed theories to explain its bonding. Later, he applied the same methods to related problems, including the structure of carboranes on which he directed the research of future Nobel Prize winner Roald Hoffmann. Lipscomb himself received the Nobel Prize in Chemistry in 1976 for his efforts.

Diborane (19287-45-7) is used in rocket propellants, as a rubber vulcaniser, as a catalyst for hydrocarbon polymerisation, as a flame-speed accelerator, and as a doping agent for the production of semiconductors. It is also used as an intermediate in the production of highly pure boron for semiconductor production.

 Diborane (19287-45-7) is so central and has been studied so often that many syntheses exist. Most preparations entail reactions of hydride donors with boron halides or alkoxides. The industrial synthesis involves the reduction of BF₃ by sodium hydride:
2 BF₃ + 6 NaH → B₂H₆ + 6 NaF
Two laboratory methods start from boron trichloride with lithium aluminium hydride or from boron trifluoride ether solution with sodium borohydride. Both methods yield in up to 30% of diborane:
4 BCl₃ + 3 LiAlH₄ → 2 B₂H₆ + 3 LiAlCl₄
4 BF₃ + 3 NaBH₄ → 2 B₂H₆ + 3 NaBF₄
Older methods entail the direct reaction of borohydride salts with a non-oxidizing acid, such as phosphoric acid or dilute sulfuric acid.
2 BH⁴⁻ + 2 H⁺ → 2 H₂ + B₂H₆
Similarly, oxidation of borohydride salts has been demonstrated and remains convenient for small scale preparations. For example, using iodine as oxidizer:
2 NaBH₄ + I₂ → 2 NaI + B₂H₆ + H₂

Reported in EPA TSCA Inventory. EPA Extremely Hazardous Substances List.

Poison by inhalation. An irritant to skin, eyes, and mucous membranes comparable to chlorine, fluorine, arsine, and phosgene. The liquid causes local inflammation, blisters, redness, and swelling. Injuries to central nervous system, liver, and kidneys have also been produced in experimental animals. Similar observations have been reported in humans, resulting at times in a reaction resembling metal fume fever. Human exposure to pentaborane has produced signs of severe central nervous system irritation such as drowsiness, dizziness, visual disturbances, muscle twitching, and in severe cases, painful muscle spasm. Dangerously flammable when exposed to heat or flame or by chemical reaction. On contact with moisture, hydrogen is usually evolved. Highly explosive when exposed to heat or flame. Explosive reaction with air, tetravinyllead, O₂ above 165°C, octanol oxime + sodium hydroxide, benzene vapor, HNO₃Cl₂. Violent reaction with halocarbon liquids. Other boron hydrides evolve H₂ upon contact with moisture or can propagate a flame rapidly enough to cause an explosion. Heat can cause these materials to decompose violently or at least to evolve H₂. They also react with water or steam to evolve hydrogen. Reaction with Al or Li forms complex hydrides that may ignite spontaneously in air. Powerful oxidizing agents, such as chlorine gas, etc., can react violently with boron hydrides. Pentaborane (stable) is spontaneously flammable in air. See also BORANES and HYDRIDES.
Hazard Codes:
T: Toxic
F+: Highly flammable
Risk Statements about Diborane (19287-45-7):
R12 Extremely flammable.
R23/24/25: Toxic by inhalation, in contact with skin and if swallowed.
R36/37/38: Irritating to eyes, respiratory system and skin.
Safety Statements about Diborane (19287-45-7):
S9 Keep container in a well-ventilated place.
S16 Keep away from sources of ignition.
S45 In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.)
S36/37/39: Wear suitable protective clothing, gloves and eye/face protection.

OSHA PEL: TWA 0.1 ppm
ACGIH TLV: TWA 0.1 ppm
DFG MAK: 0.1 ppm (0.1 mg/m³)
DOT Classification:  2.1; Label: Flammable Gas (NA 1911); DOT Class: 2.3; Label: Poison Gas, Flammable Gas

For occupational chemical analysis use NIOSH: Diborane, 6006.

 Diborane (19287-45-7) is the chemical compound consisting of boron and hydrogen with the formula B₂H₆. It is a colorless gas at room temperature with a repulsively sweet odor.Diborane mixes well with air, easily forming explosive mixtures.It will ignite spontaneously in moist air at room temperature.It is also a key boron compound with a variety of applications. The compound is classified as "endothermic," meaning that its heat of formation, ΔH°_f is positive (36 kJ/mol). Despite its thermodynamic instability, diborane is kinetically robust and exhibits an extensive chemistry, much of it entailing loss of hydrogen.