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2NaF ( s ) + SiF 4 ( g ) Na 2 SiF 6 ( s )

Antimony reacts readily with stoichiometric amounts of fluorine, chlorine, bromine, or iodine, yielding trihalides or, with excess fluorine or chlorine, forming the pentahalides SbF 5 and SbCl 5 . Depending on the stoichiometry, it forms antimony(III) sulfide, Sb 2 S 3 , or antimony(V) sulfide when heated with sulfur. As expected, the metallic nature of the element is greater than that of arsenic, which lies immediately above it in group 15.

Boron and silicon halides

Boron trihalides—BF 3 , BCl 3 , BBr 3 , and BI 3 —can be prepared by the direct reaction of the elements. These nonpolar molecules contain boron with sp 2 hybridization and a trigonal planar molecular geometry. The fluoride and chloride compounds are colorless gasses, the bromide is a liquid, and the iodide is a white crystalline solid.

Except for boron trifluoride, the boron trihalides readily hydrolyze in water to form boric acid and the corresponding hydrohalic acid. Boron trichloride reacts according to the equation:

BCl 3 ( g ) + 3H 2 O ( l ) B (OH) 3 ( a q ) + 3HCl ( a q )

Boron trifluoride reacts with hydrofluoric acid, to yield a solution of fluoroboric acid, HBF 4 :

BF 3 ( a q ) + HF ( a q ) + H 2 O ( l ) H 3 O + ( a q ) + BF 4 ( a q )

In this reaction, the BF 3 molecule acts as the Lewis acid (electron pair acceptor) and accepts a pair of electrons from a fluoride ion:

Two Lewis structures are drawn and connected by a right-facing arrow. The left structure shows a boron atom surrounded by four fluorine atoms, each with four lone pairs of electrons. The left fluorine atom has a positive and negative symbol drawn next to it. The second image is the same as the first except the positive and negative signs are missing and the entire structure is surrounded by brackets. There is a negative sign outside and superscript to the brackets.

All the tetrahalides of silicon, SiX 4 , have been prepared. Silicon tetrachloride can be prepared by direct chlorination at elevated temperatures or by heating silicon dioxide with chlorine and carbon:

SiO 2 ( s ) + 2C ( s ) + 2Cl 2 ( g ) Δ SiCl 4 ( g ) + 2CO ( g )

Silicon tetrachloride is a covalent tetrahedral molecule, which is a nonpolar, low-boiling (57 °C), colorless liquid.

It is possible to prepare silicon tetrafluoride by the reaction of silicon dioxide with hydrofluoric acid:

SiO 2 ( s ) + 4HF ( g ) SiF 4 ( g ) + 2H 2 O ( l ) Δ H ° = −191.2 kJ

Hydrofluoric acid is the only common acid that will react with silicon dioxide or silicates. This reaction occurs because the silicon-fluorine bond is the only bond that silicon forms that is stronger than the silicon-oxygen bond. For this reason, it is possible to store all common acids, other than hydrofluoric acid, in glass containers.

Except for silicon tetrafluoride, silicon halides are extremely sensitive to water. Upon exposure to water, SiCl 4 reacts rapidly with hydroxide groups, replacing all four chlorine atoms to produce unstable orthosilicic acid, Si(OH) 4 or H 4 SiO 4 , which slowly decomposes into SiO 2 .

Boron and silicon oxides and derivatives

Boron burns at 700 °C in oxygen, forming boric oxide, B 2 O 3 . Boric oxide is necessary for the production of heat-resistant borosilicate glass, like that shown in [link] and certain optical glasses. Boric oxide dissolves in hot water to form boric acid, B(OH) 3 :

B 2 O 3 ( s ) + 3H 2 O ( l ) 2B (OH) 3 ( a q )
A photo of beakers, flasks, and graduated cylinders is shown. Each piece of glassware holds a different color liquid.
Laboratory glassware, such as Pyrex and Kimax, is made of borosilicate glass because it does not break when heated. The inclusion of borates in the glass helps to mediate the effects of thermal expansion and contraction. This reduces the likelihood of thermal shock, which causes silicate glass to crack upon rapid heating or cooling. (credit: “Tweenk”/Wikimedia Commons)

Questions & Answers

is methane a molecule
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calculations for solubility
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Whats d IUPAC Numenclature of bromine
Emmanuel Reply
The common name is therefore propyl bromide . For the IUPAC name , the prefix for bromine (bromo) is combined with the name for a three-carbon chain (propane), preceded by a number identifying the carbon atom to which the Br atom is attached, so the IUPAC name is 1-bromopropane.
What is Quantum number
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A mixture is a mix of substances that can be separated
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chemistry is the study of matter and changes it undergoes
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Combustion of Methane The reactants are on the left side of the equation and the products are on the right. In the reaction, the bonds in the methane and oxygen come apart, the atoms rearrange and then re-bond to form water and carbon dioxide.
how is ethanol produced using ethene
Ethanol is manufactured by reacting ethene with steam. The reaction is reversible, and the formation of the ethanol is exothermic. Only 5% of the ethene is converted intoethanol at each pass through the reactor
Ethanol can be made by reacting ethene (from cracking crude oil fractions) with steam. A catalyst of phosphoric acid is used to ensure a fast reaction. Notice that ethanol is the only product. The process is continuous – as long as ethene and steam are fed into one end of the reaction vessel, ethano
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Differentiate between latent heat and specific latent heat of fusion and vaporization
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Ans: The amount of heat energy released or absorbed when a solid changing to liquid at atmospheric pressure at its melting point is known as the latent heat of fusion. while Vaporization of an element or compound is a phase transition from the liquid phase to vapor.
Practice Key Terms 4

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Source:  OpenStax, Chemistry. OpenStax CNX. May 20, 2015 Download for free at http://legacy.cnx.org/content/col11760/1.9
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