7789-66-4

Basic information

• Product Name: SILICON TETRABROMIDE
• Synonyms: SILICON TETRABROMIDE;SILICON(IV) BROMIDE;Silicon(IV) bromide(tetrabromosilane);SILICON BROMIDE;SiBr4;Silane, tetrabromo-;Silane,tetrabromo-;tetrabromo-silan
• CAS NO: 7789-66-4
• Molecular Formula: Br₄Si
• Molecular Weight: 347.7
• EINECS: 232-182-4
• Product Categories: metal halide
• Mol File: 7789-66-4.mol
• Article Data: 6

Chemical Properties

• Melting Point: 5 °C(lit.)
• Boiling Point: 153 °C(lit.)
• Flash Point: 154°C
• Appearance: Colorless to pale yellow/Liquid
• Density: 2.8 g/mL at 25 °C(lit.)
• Vapor Density: 2.8 (vs air)
• Refractive Index: 1.5627
• Water Solubility: decomposed in water to HBr, silicic acid, with evolution of heat [MER06]
• Sensitive: Moisture Sensitive
• Merck: 14,8499
• CAS DataBase Reference: SILICON TETRABROMIDE(CAS DataBase Reference)
• NIST Chemistry Reference: SILICON TETRABROMIDE(7789-66-4)
• EPA Substance Registry System: SILICON TETRABROMIDE(7789-66-4)

Safety Data

• Hazard Codes: C
• Statements: 34
• Safety Statements: 26-27-28-36/37/39
• RIDADR: UN 3264 8/PG 2
• WGK Germany: 3
• F: 10-23
• TSCA: Yes
• HazardClass: 8
• PackingGroup: II
• Hazardous Substances Data: 7789-66-4(Hazardous Substances Data)

Usage

Chemical Properties

Fuming, colorless liquid that turns yel- low in air; disagreeable odor. Decomposed by water with evolution of heat. Noncombustible.

Uses

Silicon tetrabromide (SiBr4) may be used to prepare photoluminescent silicon nanocrystals by chemical reduction with alkaline metals.

Hazard

Strong irritant to tissue.

InChI:InChI=1/4BrH.H4Si/h4*1H;1H4/p-4

Synthetic route

phenyltribromosilane (10581-00-7) + hydrogen bromide (10035-10-6, 12258-64-9) → tetrabromosilane (7789-66-4)

Conditions	Yield
With aluminum tri-bromide In benzene byproducts: PhH; 12 h, room temp.; 5-6 h, 70°C; distn.;	99.4%

silicon (7440-21-3) → Diphenyldibromsilan (4072-00-8) + phenyltribromosilane (10581-00-7) + tetrabromosilane (7789-66-4)

Conditions	Yield
With C6H5Br; copper In neat (no solvent) Si-Cu (8:2) and C6H5Br at about 420°C;;	A 27% B 42% C 13%

tetrachlorosilane (10026-04-7, 53609-55-5) + hexabromobenzene (87-82-1) → tetrabromosilane (7789-66-4) + dibromo dichlorosilane (13465-75-3) + bromo trichloro silane (13465-74-2) + chloro tribromo silane (13465-76-4)

Conditions	Yield
In gas High Pressure; reagents added to tube in dry ice bath, sealed in amts. to develop about 30-50 atm of pressure at 300°C, heated at 310-350°C for 1.5-69 h; analyzed by GLC;

silver(I) bromide + silicon (7440-21-3) → tetrabromosilane (7789-66-4)

Conditions	Yield
above m.p. of AgBr in vac.;

hydrogen bromide (10035-10-6, 12258-64-9) + silicon (7440-21-3) → tribromosilane (7789-57-3) + tetrabromosilane (7789-66-4)

Conditions	Yield
340-360 °C;
340-360 °C;
In neat (no solvent) moderate heating of Si in a dry HBr stream;;
In neat (no solvent) heating of Si in a HBr stream below red heat;; fractional distillation;;

Cu(b),Si(10) (X%) + hydrogen bromide (10035-10-6, 12258-64-9) → tribromosilane (7789-57-3) + tetrabromosilane (7789-66-4)

carbonyl dibromide (593-95-3) + silica gel (112926-00-8, 7631-86-9) → tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent) byproducts: Si2OBr6, bromine, carbon monoxide; >1000 K;

Cu(20),Si(80) (X%) + hydrogen bromide (10035-10-6, 12258-64-9) → tribromosilane (7789-57-3) + tetrabromosilane (7789-66-4)

bromo trichloro silane (13465-74-2) → tetrachlorosilane (10026-04-7, 53609-55-5) + tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent) passing SiBrCl3 through a tube, heated at 600 °C;;
In neat (no solvent) passing SiBrCl3 through a tube, heated at 600 °C;;

bromo trichloro silane (13465-74-2) + chloro tribromo silane (13465-76-4) → tetrachlorosilane (10026-04-7, 53609-55-5) + tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent) passing a mixture of SiBrCl3 and SiBr3Cl through a tube, heated at 600 °C;;
In neat (no solvent) passing a mixture of SiBrCl3 and SiBr3Cl through a tube, heated at 600 °C;;

difluorosilylene (13966-66-0) + bromine (7726-95-6) + silicon tetrafluoride (7783-61-1) → bromotrifluorosilane (14049-39-9) + difluoro dibromosilane (14188-35-3) + fluoro tribromosilane (18356-67-7) + disilicon hexabromide (13517-13-0) + tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent) The halogen was co-condensed in a flask at -196°C with the mixt. of SiF4 and SiF2 emerging out of the reactor tube; further products;; warmed to room temp.; the volatile products were sepd. and detected by NMR and MS;;

bromine (7726-95-6) + silicon (7440-21-3) → tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent) passing of a N2 stream with Br2 vapor over crystalline Si which is heated at 1000°C;; removal of Br2 by heating and shaking with Hg;;	>99
In neat (no solvent) passing of a N2 stream with Br2 vapor over crystalline Si which is heated at 1000°C;; removal of Br2 by heating and shaking with Hg;;	>99
In neat (no solvent) removal of Br2 by shaking with Hg; purification by fractional distillation;;
Inert atmosphere;

bromine (7726-95-6) + chlorine (7782-50-5) + silicon (7440-21-3) → tetrabromosilane (7789-66-4) + dibromo dichlorosilane (13465-75-3) + bromo trichloro silane (13465-74-2) + chloro tribromo silane (13465-76-4)

Conditions	Yield
In neat (no solvent) passing a mixture of Cl2 and Br2 over metallic Si at 700°C;; fractional distillation;;

bromine (7726-95-6) + silicon tetraiodide (13465-84-4) → tribromo iodosilane (13536-76-0) + tetrabromosilane (7789-66-4)

Conditions	Yield
In carbon disulfide
In neat (no solvent)
In carbon disulfide

bromine (7726-95-6) + monosilane (7440-21-3) → tribromosilane (7789-57-3) + silyl bromide (14791-57-2) + dibromosilane (13768-94-0) + hydrogen bromide (10035-10-6, 12258-64-9) + tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent) reaction of Br2 and excess SiH4; cooling;; fractionation;;
In neat (no solvent) reaction of Br2 and excess SiH4; cooling;; fractionation;;

Fe(b),Si(75) (X%) + bromine (7726-95-6) → disilicon hexabromide (13517-13-0) + tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent) byproducts: HBr; heating of ferrosilicon with 25% Fe in a N2 stream with Br2 vapor in a porcelaine tube at 800-850°C;; removal of Br2 by shaking with Hg; isolation by fractional distillation and condensation in vacuum;;

bromine (7726-95-6) + silica gel (112926-00-8, 7631-86-9) → tetrabromosilane (7789-66-4) + chloro tribromo silane (13465-76-4)

Conditions	Yield
With C In neat (no solvent) treatment of a mixture of SiO2 and C with crude Br2 at higher temp.;; fractionation;;

bromine (7726-95-6) + silica gel (112926-00-8, 7631-86-9) → tetrabromosilane (7789-66-4)

Conditions	Yield
With oil; Sucrose In neat (no solvent) passing of Br2 vapor over the mixture at glowing heat;; removal of Br2 by shaking with Hg; purification by distillation;;
With carbon monoxide In neat (no solvent) byproducts: carbon dioxide; addn. of SiO2, CO (22-28 kP) and Br2 (27-40 kP) into ampoule, reactn. at 837 K (24 h); detn. of SiBr4 after heating the evacuated ampoule at >1173 K;
With carbon monoxide In neat (no solvent) byproducts: carbon dioxide; addn. of SiO2, CO (22-28 kP) and Br2 (27-40 kP) into ampoule, reactn. at >1173 K (24 h); no detn. of COBr2 in vapour phase;
With C In neat (no solvent) passing of Br2 vapor over the mixture at glowing heat;; removal of Br2 by passing H2 through the crude bromide on heating; shaking with Hg and fractional distillation;;
With soot; sugar; oil In neat (no solvent) passing of Br2 vapor over the mixture at glowing heat;; removal of Br2 by shaking with Hg; purification by distillation;;

tribromosilane (7789-57-3) → tetrabromosilane (7789-66-4) + silicon (7440-21-3)

Conditions	Yield
In neat (no solvent) byproducts: H2; decompn. above 700 °C;;
In neat (no solvent) byproducts: H2; decompn. above 700 °C;;

copper(I) bromide (7787-70-4) + silicon (7440-21-3) → tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent)
In neat (no solvent)

silica + beryllium bromide → tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent) byproducts: BeO; reaction of BeBr2 with quartz glass at high temp.;;

hydrogen bromide (10035-10-6, 12258-64-9) + silicon (7440-21-3) → tribromosilane (7789-57-3) + silyl bromide (14791-57-2) + dibromosilane (13768-94-0) + tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent)
In neat (no solvent) reaction of crystalline Si with gaseous HBr at 340-700 °C; yields depend on the reaction temperature;;	A n/a B <1 C n/a D n/a
In neat (no solvent)
In neat (no solvent) reaction of crystalline Si with gaseous HBr at 340-700 °C; yields depend on the reaction temperature;;	A n/a B <1 C n/a D n/a

hydrogen bromide (10035-10-6, 12258-64-9) + silicon (7440-21-3) → silicon tribromide (13842-48-3) + tetrabromosilane (7789-66-4)

Conditions	Yield
In neat (no solvent) reaction at temperatures between 340 und 360 °C;;
In neat (no solvent) reaction at temperatures between 340 und 360 °C;;
In neat (no solvent) reaction at temperatures between 340 und 360 °C;;

Upstream product

• 20786-96-3 hexabromo disiloxane 
• 7789-33-5 iodine(I) bromide 
• 7440-21-3 silicon 
• 10035-10-6 hydrogen bromide 
• 7787-70-4 copper(I) bromide 
• 7789-57-3 tribromosilane 
• 7726-95-6 bromine 
• 112926-00-8 silica gel 
• 7440-21-3 monosilane 
• 13465-84-4 silicon tetraiodide 
• 7782-50-5 chlorine 
• 13966-66-0 difluorosilylene 
• 7783-61-1 silicon tetrafluoride 
• 13465-74-2 bromo trichloro silane 

Downstream Products

• 2857-97-8 trimethylsilyl bromide 
• 1048-08-4 tetraphenylsilane 
• 1524-78-3 perfluorotetraphenylsilane 
• 35369-96-1 bis-(pentafluoro phenyl) bromo ethoxy silane 
• 229467-44-1 (2-tert-butyl-6-methylphenyl-O)2TiBr₂ 
• 14067-07-3 silicon ion 
• 12350-21-9 SiBr⁽¹⁺⁾ 
• 138852-82-1 SiBr₂⁽¹⁺⁾ 
• 138852-83-2 SiBr₃⁽¹⁺⁾ 
• 13272-95-2 (4-ans)SiBr₃ 
• 27890-58-0 Si tetraazide 
• 112926-00-8 silica gel 
• 10026-04-7 tetrachlorosilane 
• 13465-75-3 dibromo dichlorosilane 

Relevant articles and documents

A simple synthesis of tetrabromosilane

We report on a synthesis of SiBr4 by reacting C6H5SiBr3 with HBr/AlBr3 to give a nearly quantitative yield. We start from C6H5SiCl3 which gives C6H5SiH3 with LiAlH4 and further on C6H5SiBr3 with Br2. Johann Ambrosius Barth 1996.

Silicon Tetrakis(trifluoromethanesulfonate): A Simple Neutral Silane Acting as a Soft and Hard Lewis Superacid

A facile synthesis and isolation of pristine silicon tetrakis(trifluoromethanesulfonate), Si(OTf)4, is reported, acting as the first neutral silicon-based Lewis superacid suitable towards soft and hard Lewis bases. Its OTf groups have a dual function: they are excellent leaving groups and modulate the degree of reactivity towards soft and hard Lewis bases. Exposed to soft Lewis donors, Si(OTf)4 leads to [L2Si(OTf)4] complexes (L=isocyanide, thioether and carbonyl compounds) with retention of all Si?OTf bonds. In contrast, it can cleave C?X bonds (X=F, Cl) of hard organic Lewis bases with a high tendency to form SiX4 (X=F, Cl) after halide/triflate exchange. Most notable, Si(OTf)4 allows a gentle oxydefluorination of mono- and bis(trifluoromethyl)benzenes, resulting in the formation of the corresponding benzoylium species, which are stabilized by the weakly coordinating [Si(OTf)6] dianion.

Reaction of Silicon Difluoride with Halogens: a Reinvestigation

Reactions of SiF2 with halogens have been reinvestigated by both co-condensation and gas-phase methods.The co-condensation method yields a number of fluorohalogenosilanes including mono-, di-, and higher silane derivatives.These compounds contain SiF, SiF2, and SiF3 units.The reactivity towards SiF2 decreases from chlorine through bromine to iodine.While chlorine and bromine give rise to a number of fluorohalogenosilanes, iodine yields only the monosilane derivatives.In contrast, the gas-phase reaction do not progress to any appreciable extent.The products have been characterized by mass spectrometry and 19F and 29Si n.m.r. spectroscopy.Many have been identified for the first time.