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Chemistry: A Molecular Approach , 1 st Ed. Nivaldo Tro. Chapter 22 Chemistry of the Nonmetals. Roy Kennedy Massachusetts Bay Community College Wellesley Hills, MA. 2008, Prentice Hall. Nanotubes. nanotubes – long, thin, hollow cylinders of atoms

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chapter 22 chemistry of the nonmetals

Chemistry: A Molecular Approach, 1st Ed.Nivaldo Tro

Chapter 22Chemistry of the Nonmetals

Roy Kennedy

Massachusetts Bay Community College

Wellesley Hills, MA

2008, Prentice Hall

nanotubes
Nanotubes
  • nanotubes – long, thin, hollow cylinders of atoms
  • carbon nanotube = sp2 C in fused hexagonal rings
    • electrical conductors
  • boron-nitride nanotubes = rings of alternating B and N atoms
    • isoelectronic with C
    • similar size to C
    • average electronegativity of B & N about the same as C
    • electrical insulators

Tro, Chemistry: A Molecular Approach

insulated nanowire
Insulated Nanowire

Tro, Chemistry: A Molecular Approach

properties of bn and c
Properties of BN and C

Tro, Chemistry: A Molecular Approach

main group nonmetals
Main Group Nonmetals

Tro, Chemistry: A Molecular Approach

atomic radius and bonding
Atomic Radius and Bonding
  • atomic radius decreases across the period
  • electronegativity, ionization energy increase across the period
  • nonmetals on right of p block form anions in ionic compounds
    • often reduced in chemical reactions
      • making them oxidizing agents
  • nonmetals on left of p block can form cations and electron-deficient species in covalent bonding
  • nonmetals near the center of the p block tend to use covalent bonding to complete their octets
  • bonding tendency changes across the period for nonmetals from cation and covalent; to just covalent; to anion and covalent

Tro, Chemistry: A Molecular Approach

silicates
Silicates
  • the most abundant elements of the Earth’s crust are O and Si
  • silicates are covalent atomic solids of Si and O
    • and minor amounts of other elements
    • found in rocks, soils, and clays
    • silicates have variable structures – leading to the variety of properties found in rocks, clays, and soils

Tro, Chemistry: A Molecular Approach

bonding in silicates
Bonding in Silicates
  • each Si forms a single covalent bond to 4 O
    • sp3 hybridization
    • tetrahedral shape
    • Si-O bond length is too long to form Si=O
  • to complete its octet, each O forms a single covalent bond to another Si
  • the result is a covalent network solid

Tro, Chemistry: A Molecular Approach

quartz
Quartz
  • a 3-dimensional covalent network of SiO4 tetrahedrons
  • generally called silica
  • formula unit is SiO2
  • when heated above 1500C and cooled quickly, get amorphous silica which we call glass

Tro, Chemistry: A Molecular Approach

aluminosilicates
Aluminosilicates
  • Al substitutes for Si in some of the lattice sites
  • SiO2 becomes AlO2−
  • the negative charge is countered by the inclusion of a cation
    • Albite = ¼ of Si replaced by Al; Na(AlO2)(SiO2)3
    • Anorthite = ½ of Si replaced by Al; Ca(AlO2)2(SiO2)2

Tro, Chemistry: A Molecular Approach

silicates made of individual units
Silicates Made of Individual Units
  • O of SiO4 picks up electrons from metal to form SiO44−
  • if the SiO44− are individual units neutralized by cations, it forms an orthosilicate
    • willemite = Zn2SiO4
  • when two SiO4 units share an O, they form structures called pyrosilicateswith the anion formula Si2O76−
    • hardystonite =Ca2ZnSi2O7

Tro, Chemistry: A Molecular Approach

single chain silicates
Single Chain Silicates
  • if the SiO44− units link as long chains with shared O, the structure is called a pyroxene
  • formula unit SiO32-
  • chains held together by ionic bonding to metal cations between the chains
    • diopside = CaMg(SiO3)2 where Ca and Mg occupy lattice points between the chains

Tro, Chemistry: A Molecular Approach

double chain silicates
Double Chain Silicates
  • some silicates have 2 chains bonded together at ½ the tetrahedra – these are called amphiboles
  • often results in fibrous minerals
    • asbestos
    • tremolite asbestos = Ca2(OH)2Mg5(Si4O11)2

Tro, Chemistry: A Molecular Approach

sheet silicates
Sheet Silicates
  • when 3 O of each tetrahedron are shared, the result is a sheet structure called a phyllosilicate
  • formula unit = Si2O52−
  • sheets are ionically bonded to metal cations that lie between the sheets
  • talc and mica

Tro, Chemistry: A Molecular Approach

mica a phyllosilicate
Mica: a Phyllosilicate

Tro, Chemistry: A Molecular Approach

silicate structures
Silicate Structures

Tro, Chemistry: A Molecular Approach

boron
Boron
  • metalloid
  • at least 5 allotropes, whose structures are icosahedrons
    • each allotrope connects the icosahedra in different ways
  • less than 0.001% in Earth’s crust, but found concentrated in certain areas
    • almost always found in compounds with O
      • borax = Na2[B4O5(OH)4]8H2O
      • kernite = Na2[B4O5(OH)4]3H2O
      • colemanite = Ca2B6O115H2O
  • used in glass manufacturing – borosilicate glass = Pyrex
  • used in control rods of nuclear reactors

Tro, Chemistry: A Molecular Approach

boron trihalides
Boron Trihalides
  • BX3
  • sp2 B
    • trigonal planar, 120 bond angles
    • forms single bonds that are shorter and stronger than sp3 C
    • some overlap of empty p on B with full p on halogen
  • strong Lewis Acids

Tro, Chemistry: A Molecular Approach

boron oxygen compounds
Boron-Oxygen Compounds
  • form structures with trigonal BO3 units
  • in B2O3, six units are linked in a flat hexagonal B6O6 ring
    • melts at 450C
      • melt dissolves many metal oxides and silicon oxides to form glasses of different compositions

Tro, Chemistry: A Molecular Approach

boranes closo boranes
Boranescloso-Boranes
  • compounds of B and H
  • used as reagent in hydrogenation of C=C
  • closo-Boranes have formula BnHn2− and form closed polyhedra with a BH unit at each vertex

Tro, Chemistry: A Molecular Approach

boranes nido boranes and arachno boranes
Boranesnido-Boranes and arachno-Boranes
  • nido-Boranes have formula BnHn+4 consisting of cage B missing one corner
  • arachno-Boranes have formula BnHn+6 consisting of cage B missing two or three corners

Tro, Chemistry: A Molecular Approach

carbon
Carbon
  • exhibits the most versatile bonding of all the elements
  • diamond structure consists of tetrahedral sp3 carbons in a 3-dimensional array
  • graphite structures consist of trigonal planar sp2 carbons in a 2-dimensional array
    • sheets attracted by weak dispersion forces
  • fullerenes consist of 5 and 6 member carbon rings fused into icosahedral spheres of at least 60 C

Tro, Chemistry: A Molecular Approach

allotropes of carbon diamond
Allotropes of Carbon - Diamond

Inert to Common Acids

Inert to Common Bases

Negative Electron Affinity

Transparent

Hardest

Best Thermal Conductor

Least Compressible

Stiffest

Tro, Chemistry: A Molecular Approach

allotropes of carbon graphite
Allotropes of Carbon - Graphite

Soft and Greasy Feeling

Solid Lubricant

Pencil “Lead”

Conducts Electricity

Reacts with Acids and Oxidizing Agents

Tro, Chemistry: A Molecular Approach

noncrystalline forms of carbon
Noncrystalline Forms of Carbon
  • coal is a mixture of hydrocarbons and carbon-rich particles
    • the product of carbonation of ancient plant material
      • carbonation removes H and O from organic compounds in the form of volatile hydrocarbons and water
  • anthracite coal has highest C content
  • bituminous coal has high C, but high S
  • heating coal in the absence of air forms coke
    • carbon and ash
  • heating wood in the absence of air forms charcoal
    • activated carbon is charcoal used to adsorb other molecules
  • soot is composed of hydrocarbons from incomplete combustion
    • carbon black is finely divided form of carbon that is a component of soot
      • used as rubber strengthener

Tro, Chemistry: A Molecular Approach

allotropes of carbon buckminsterfullerene
Allotropes of Carbon - Buckminsterfullerene

Sublimes between 800°C

Insoluble in water

Soluble in toluene

Stable in air

Requires temps > 1000°C to decompose

High electronegativity

Reacts with alkali metals

Behavior more aliphatic than aromatic

Tro, Chemistry: A Molecular Approach

nanotubes1
Nanotubes
  • long hollow tubes constructed of fused C6 rings
  • electrical conductors
  • can incorporate metals and other small molecules and elements
    • used to stabilize unstable molecules
  • single-walled nanotubes (SWNT) have one layer of fused rings
  • multi-walled nanotubes (MWNT) have concentric layers of fused rings

Tro, Chemistry: A Molecular Approach

nanotubes2
Nanotubes

Tro, Chemistry: A Molecular Approach

nanocars
Nanocars

Tro, Chemistry: A Molecular Approach

carbides
Carbides
  • carbides are binary compounds of C with a less electronegative element
  • ionic carbides are compounds of metals with C
    • generally alkali or alkali earth metals
    • often dicarbide ion, C22− (aka acetylide ion)
    • react with water to form acetylene, C2H2
  • covalent carbides are compounds of C with a low-electronegativity nonmetal or metalloid
    • silicon carbide, SiC (aka carborundum)
      • very hard
  • metallic carbides are metals in which C sits in holes in the metal lattice
    • hardens and strengthens the metal without affecting electrical conductivity
    • steel and tungsten carbide

Tro, Chemistry: A Molecular Approach

calcium carbide
Calcium Carbide

Tro, Chemistry: A Molecular Approach

cementite fe 3 c regions found in steel
CementiteFe3C regions found in steel

Tro, Chemistry: A Molecular Approach

carbon oxides
Carbon Oxides
  • CO2
    • 0.04% in atmosphere
      • increased by 25% over the past century
    • high solubility in water
      • due to reaction with water to form HCO3− ions
    • triple point −57C and 5.1 atm
      • liquid CO2 doesn’t exist at atmospheric pressure
      • solid CO2 = dry ice
  • CO
    • colorless, odorless, tasteless gas
    • relatively reactive
      • 2 CO + O2  2 CO2
        • burns with a blue flame
      • reduces many nonmetals
        • CO + Cl2  COCl2 (phosgene)
        • CO + S  COS (fungicide)

Tro, Chemistry: A Molecular Approach

carbonates
Carbonates
  • solubility of CO2 in H2O due to carbonate formation
    • CO2 + H2O  H2CO3
    • H2CO3 + H2O  H3O+ + HCO3−
    • HCO3−+ H2O  H3O+ + CO32−
  • washing soda = Na2CO310H2O
    • doesn’t decompose on heating
  • all carbonate solutions are basic in water
    • due to CO32−+ H2O  OH− + HCO32−
  • baking soda = NaHCO3
    • decomposes on heating to Na2CO3, H2O and CO2

Tro, Chemistry: A Molecular Approach

elemental nitrogen
Elemental Nitrogen
  • N2
    • 78% of atmosphere
    • purified by distillation of liquid air, or filtering air through zeolites
    • very stable, very unreactive
      • NN

Tro, Chemistry: A Molecular Approach

elemental phosphorus
Elemental Phosphorus
  • P
    • white phosphorus
      • white, soft, waxy solid that is flammable and toxic
      • stored under water to prevent spontaneous combustion
      • 2 Ca3(PO4)2 (apatite) + 6 SiO2 + 10 C  P4(g, wh) + 6 CaSiO3 + 10 CO
      • tetrahedron with small angles 60
    • red phosphorus
      • formed by heating white P to about 300C in absence of air
      • amorphous
      • mostly linked tetrahedra
      • not as reactive or toxic as white P
      • used in match heads
    • black phosphorus
      • formed by heating white P under pressure
      • most thermodynamically stable form, therefore least reactive
      • layered structure similar to graphite

Tro, Chemistry: A Molecular Approach

phosphorus

White Phosphorus

Red Phosphorus

Phosphorus

Tro, Chemistry: A Molecular Approach

hydrides of nitrogen
Hydrides of Nitrogen
  • ammonia, NH3
    • pungent gas
    • basic NH3 + H2O  NH4+ + OH−
      • reacts with acids to make NH4+ salts
        • used as chemical fertilizers
    • made by fixing N from N2 using the Haber-Bosch process
  • hydrazine, N2H4
    • colorless liquid
    • basic N2H4 + H2O  N2H5+ + OH−
    • powerful reducing agent
  • hydrogen azide, HN3
    • acidic HN3 + H2O  H3O+ + N3−
    • thermodynamically unstable and decomposes explosively to its elements

Tro, Chemistry: A Molecular Approach

hydrazine
Hydrazine

Tro, Chemistry: A Molecular Approach

oxides of nitrogen
Oxides of Nitrogen
  • formed by reaction of N2 or NOx with O2
  • all unstable and will eventually decompose into N2 and O2
  • NO = nitrogen monoxide = nitric oxide
    • important in living systems
    • free radical
  • NO2 = nitrogen dioxide
    • 2 NO2 N2O4
    • red-brown gas
    • free radical
  • N2O = dinitrogen monoxide = nitrous oxide
    • laughing gas
    • made by heating ammonium nitrate NH4NO3  N2O + H2O
    • oxidizing agent Mg + N2O  N2 + MgO
    • decomposes on heating 2 N2O  2 N2 + O2
    • pressurize food dispensers

Tro, Chemistry: A Molecular Approach

nitric acid
Nitric Acid
  • HNO3 = nitric acid
    • produced by the Ostwald Process

4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g)

2 NO(g) + O2(g)  2 NO2(g)

3 NO2(g) + H2O(l)  2 HNO3(l) + NO(g)

    • strong acid
    • strong oxidizing agent
    • concentrated = 70% by mass = 16 M
      • some HNO3 in bottle reacts with H2O to form NO2
    • main use to produce fertilizers and explosives

NH3(g) + HNO3(aq)  NH4NO3(aq)

Tro, Chemistry: A Molecular Approach

nitrates and nitrites
Nitrates and Nitrites
  • NO3− = nitrate
    • ANFO = ammonium nitrate fuel oil
      • used as explosive in Oklahoma City
    • ammonium nitrate can decompose explosively
      • and other nitrates

2 NH4NO3 2 N2 + O2 + 4 H2O

    • metal nitrates used to give colors to fireworks
    • very soluble in water
    • oxidizing agent
  • NO2− = nitrite
    • NaNO2 used as food preservative in processed meats
      • kills botulism bacteria
      • keeps meat from browning when exposed to air
      • can form nitrosamines which may increase risk of colon cancer??

Tro, Chemistry: A Molecular Approach

phosphine
Phosphine
  • PH3
    • colorless, poisonous gas that smells like rotting fish
    • formed by reacting metal phosphides with water

Ca3P2(s) + 6 H2O(l) 2 PH3(g) + 3 Ca(OH)2(aq)

    • also by reaction of wh P with H2O in basic solution

2 P4(s) + 9 H2O(l) + 3 OH−(aq) 5 PH3(g) + 3 H2PO4−(aq)

    • decomposes on heating to elements

4 PH3(g) P4(s) + 6 H2(g)

    • reacts with acids to form PH4+ ion
    • does not form basic solutions

Tro, Chemistry: A Molecular Approach

phosphorus halides
Phosphorus Halides
  • P4 can react directly with halogens to form PX3 and PX5 compounds
  • PX3 can react with water to form H3PO3
    • PX5 can react with water to form H3PO4

PCl3(l) + 3 H2O(l) H3PO3(aq) + 3 HCl(aq)

  • PCl3 reacts with O2 to form POCl3(l)
    • phosphorus oxychloride
    • other oxyhalides made by substitution on POCl3
  • phosphous halide and oxyhalides are key starting materials in the production of many P compounds
    • fertilizers, pesticides, oil-additives, fire-retardants, surfactants

Tro, Chemistry: A Molecular Approach

phosphorus oxides
Phosphorus Oxides
  • P4 reacts with O2 to make P4O6(s) or P4O10(s)
    • get P4O10 with excess O2

Tro, Chemistry: A Molecular Approach

phosphoric acid and phosphates
Phosphoric Acid and Phosphates
  • H3PO4 = phosphoric acid
    • white solid that melts at 42C
    • concentrated = 85% by mass = 14.7 M
    • produced by reacting P4O10 with water or the reaction of Ca3(PO4)2 with sulfuric acid

P4O10(s) + 6 H2O(l) 4 H3PO4(aq)

Ca3(PO4)2(s) + 3 H2SO4(l) 3 CaSO4(s) + 2 H3PO4(qa)

    • used in rust removal, fertilizers, detergent additives and food preservative
      • sodium pyrophosphate = Na4P2O7
      • sodium tripolyphosphate = Na5P3O10

Tro, Chemistry: A Molecular Approach

use of phosphates in food
Use of Phosphates in Food

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oxygen
Oxygen
  • 2s22p4
    • 6 valence electrons
  • stronger oxidizing agent than other 6A elements
    • used by living system to acquire energy
  • second highest electronegativity (3.5)
  • very high abundance in crust, and highest abundance of any element on Earth
  • found in most common compounds

Tro, Chemistry: A Molecular Approach

elemental oxygen
Elemental Oxygen
  • O2
    • nonpolar, colorless, odorless gas
    • freezing point −183C at which it becomes a pale blue liquid
    • slightly soluble in water
      • 0.04 g/L
    • mainly produced by fractional distillation of air
      • also by the electrolysis of water
    • can be synthesized by heating metal oxides, chlorates, or nitrates

HgO(s)  Hg(l) + O2(g)

2 NaNO3(s)  2 NaNO2(s) + O2(g)

2 KClO3(s)  2 KCl(s) + 3 O2(g)

    • used in high temperature combustion
      • blast furnace, oxyacetylene torch
    • used to create artificial atmospheres
      • divers, high-altitude flight
    • medical treatment
      • lung disease, hyperbaric O2 to treat skin wounds

Tro, Chemistry: A Molecular Approach

oxides
Oxides
  • reacts with most other elements to form oxides
    • both metals and nonmetals
  • oxides containing O2− with −2 oxidation state most stable for small ions with high charge
  • oxides containing O2− with −½ oxidation state most stable for large ions with smaller charge

Tro, Chemistry: A Molecular Approach

ozone
Ozone
  • O3
    • toxic, pungent, blue, diamagnetic gas
    • denser than O2
    • freezing point −112C, where it becomes a blue liquid
    • synthesized naturally from O2 through the activation by ultraviolet light
      • mainly in the stratosphere
      • protecting the living Earth from harmful UV rays
    • spontaneously decomposes into O2
    • commercial use as a strong oxidizing agent and disinfectant
    • formed in the troposphere by interaction of UV light and auto exhaust
      • oxidation damages skin, lungs, eyes, and cracks plastics and rubbers

Tro, Chemistry: A Molecular Approach

sulfur
Sulfur
  • large atom and weaker oxidizer than oxygen
  • often shows +2, +4, or +6 oxidation numbers in its compounds, as well as −2
  • composes 0.06% of Earth’s crust
  • elemental sulfur found in a few natural deposits
    • some on the surface
  • below ground recovered by the Frasch Process
    • superheated water pumped down into deposit, melting the sulfur and forcing it up the recovery pipe with the water
  • also obtained from byproducts of several industrial processes

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natural sulfur deposit
Natural Sulfur Deposit

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frasch process
Frasch Process

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allotropes of sulfur
Allotropes of Sulfur
  • several crystalline forms
  • the most common naturally occurring allotrope has S8 rings
    • most others also ring structures of various sizes
  • when heated to 112C, S8 melts to a yellow liquid with low viscosity
  • when heated above 150C, rings start breaking and a dark brown viscous liquid forms
    • darkest at 180C
    • above 180C the liquid becomes less viscous
  • if the hot liquid is quenched in cold water, a plastic amorphous solid forms that becomes brittle and hard on cooling

Tro, Chemistry: A Molecular Approach

slide58

sulfur at ~150C

sulfur at ~180C

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amorphous sulfur
Amorphous Sulfur

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other sources of sulfur
Other Sources of Sulfur
  • H2S(g) from oil and natural gas deposits
    • toxic gas (death > 100 ppm), smells like rotten eggs
    • bond angle only 92.5
    • nonpolar
    • S-H bond weaker and longer than O-H bond
    • oxidized to elemental S through the Claus Process

2 H2S(g) + 2 O2(g)  2 SO2(g) + 2 H2O(g)

4 H2S(g) + 2 SO2(g)  6 S(s) + 4 H2O(g)

  • FeS2 (iron pyrite)
    • roasted in absence of air forming FeS(s) and S2(g)
  • metal sulfides
    • roasted in air to make SO2(g), which is later reduced
    • react with acids to make H2S
    • most insoluble in water
    • used as bactericide and stop dandruff in shampoo

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metal sulfides
Metal Sulfides

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sulfur dioxide
Sulfur Dioxide
  • SO2
    • colorless, dense, acrid gas that is toxic
    • produced naturally by volcanic action and as a byproduct of industrial processes
      • including electrical generation by burning oil and coal, as well as metal extraction
    • acidic

SO2(g) + H2O(l) H2SO3(aq)

    • forms acid rain in the air

2 SO2(g) + O2(g) + 2 H2O(l) 2 H2SO4(aq)

    • removed from stack by scrubbing with limestone

CaCO3(s) CaO(s) + O2(g)

2 CaO(g) + 2 SO2(g) + O2(g) 2 CaSO4(g)

    • used to treat fruits and vegetables as a preservative

Tro, Chemistry: A Molecular Approach

sulfuric acid
Sulfuric Acid
  • most produced chemical in the world
  • strong acid, good oxidizing agent, dehydrating agent
  • used in production of fertilizers, dyes, petrochemicals, paints, plastics, explosives, batteries, steel, and detergents
  • melting point 10.4C, boiling point 337C
    • oily, dense liquid at room temperature
  • reacts vigorously and exothermically with water
    • “you always oughter(sic) add acid to water”

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dehydration of sucrose
Dehydration of Sucrose

C12H22O11(s) + H2SO4(l)  12 C(s) + 11 H2O(g) + H2SO4(aq)

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production of h 2 so 4
Production of H2SO4
  • contact process
  • step 1: combustion of elemental S
    • complete using V2O5 catalyst

S(g) + O2(g) SO2(g)

2 SO2(g) + O2(g) 2 SO3(g)

  • step 2: absorbing the SO2 into conc. H2SO4 to form oleum, H2S2O7

SO3(g) + H2SO4(l) H2S2O7(l)

  • step 3: dissolve the oleum in water

H2S2O7(l) + H2O(l) 2 H2SO4(aq)

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halogens
Halogens
  • most reactive nonmetal group
  • never found in elemental form in nature
  • come from dissolved salts in seawater
    • except fluorine, which comes from minerals fluorospar (CaF2) and fluoroapatite [Ca10F2(PO4)6]
  • atomic radius increases down the column
  • most electronegative element in its period, decreasing down the column
  • fluorine only has oxidation states of -1 or 0, others have oxidation states ranging from -1 to +7

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properties of the halogens
Properties of the Halogens

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fluorine
Fluorine
  • F2 is a yellow-green toxic gas
  • F2 is the most reactive nonmetal and forms binary compounds with every element except He, Ne, and Ar
    • including XeF2, XeF6, XeOF4, KrF2
    • so reactive it reacts with other elements of low reactivity resulting in flames
    • even reacts with the very unreactive asbestos and glass
      • stored in Fe, Cu, or Ni containers because the metal fluoride that forms coats the surface protecting the rest of the metal
  • F2 bond weakest of the X2 bonds, allowing reactions to be more exothermic
  • small ion size of F− leads to large lattice energies in ionic compounds
  • produced by the electrolysis of HF

Tro, Chemistry: A Molecular Approach

hydrofluoric acid
Hydrofluoric Acid
  • HF
    • produced by the reaction of fluorospar with H2SO4

CaF2(s)+ H2SO4(l) CaSO4(s) + 2 HF(g)

    • crystalline HF is zig-zag chains
    • HF is weak acid, Ka = 6.8 x 10-4 at 25C
    • F− can combine with HF to form complex ion HF2−
      • with bridging H
    • strong oxidizing agent
      • strong enough to react with glass, so generally stored in plastic
      • used to etch glass

SiO2(g) + 4 HF(aq)  SiF4(g) + H2O(l)

    • very toxic because it penetrates tissues and reacts with internal organs and bones

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halogen compounds
Halogen Compounds
  • form ionic compounds with metals and molecular compounds having covalent bonds with nonmetals
  • halogens can also form compounds with other halogens – called interhalides
    • for interhalides, the larger has lower electronegativity – so it is central in the molecule; with a number of more electronegative halides attached
    • general formula ABn where n can be 1, 3, 5, or 7
      • most common AB or AB3; only AB5 has B = F, IF7 only known n = 7
    • only ClF3 used industrially
      • to produce UF6 in nuclear fuel enrichment
  • most halogen oxides are unstable
    • tend to be explosive
    • OF2 only compound with O = +2 oxidation state
    • ClO2(g) is strong oxidizer used to bleach flour and wood pulp
      • explosive – so diluted with CO2 and N2
      • produced by oxidation of NaClO2 with Cl2 or the reduction of NaClO3 with HCl

2 NaClO2 + Cl2 2 NaCl + 2 ClO2

2 NaClO3 + 4 HCl  2 ClO2 + 2 H2O + 2 NaCl

Tro, Chemistry: A Molecular Approach