Chemistry A Molecular Approach 1 st Ed Nivaldo

Chemistry: A Molecular Approach, 1 st Ed. Nivaldo Tro Chapter 22 Chemistry of the Nonmetals Roy Kennedy Massachusetts Bay Community College Wellesley Hills, MA Tro, Chemistry: A Molecular Approach 2008, Prentice Hall

Nanotubes • nanotubes – long, thin, hollow cylinders of atoms • carbon nanotube = sp 2 C in fused hexagonal rings ü electrical conductors • boron-nitride nanotubes = rings of alternating B and N atoms ü isoelectronic with C ü similar size to C ü average electronegativity of B & N about the same as C ü electrical insulators Tro, Chemistry: A Molecular Approach 2

Properties of BN and C Tro, Chemistry: A Molecular Approach 3

Main Group Nonmetals Tro, Chemistry: A Molecular Approach 4

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 ü often reduced in chemical reactions Ø 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 5

Insulated Nanowire Tro, Chemistry: A Molecular Approach 6

Silicates • the most abundant elements of the Earth’s crust • are O and Si silicates are covalent atomic solids of Si and O üand minor amounts of other elements üfound in rocks, soils, and clays üsilicates have variable structures – leading to the variety of properties found in rocks, clays, and soils Tro, Chemistry: A Molecular Approach 7

Bonding in Silicates • each Si forms a single covalent bond to 4 O üsp 3 hybridization ütetrahedral shape üSi-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 8

Quartz • a 3 -dimensional covalent • • • network of Si. O 4 tetrahedrons generally called silica formula unit is Si. O 2 when heated above 1500 C and cooled quickly, get amorphous silica which we call glass Tro, Chemistry: A Molecular Approach 9

Aluminosilicates • Al substitutes for Si in some of the lattice sites • Si. O 2 becomes Al. O 2− • the negative charge is countered by the inclusion of a cation üAlbite = ¼ of Si replaced by Al; Na(Al. O 2)(Si. O 2)3 üAnorthite = ½ of Si replaced by Al; Ca(Al. O 2)2(Si. O 2)2 Tro, Chemistry: A Molecular Approach 10

Silicates Made of Individual Units • O of Si. O 4 picks up electrons from metal to form Si. O 44− • if the Si. O 44− are individual units neutralized by cations, it forms an orthosilicate ü willemite = Zn 2 Si. O 4 • when two Si. O 4 units share an O, they form structures called pyrosilicates with the anion formula Si 2 O 76− ü hardystonite =Ca 2 Zn. Si 2 O 7 Tro, Chemistry: A Molecular Approach 11

Single Chain Silicates • if the Si. O 44− units link as long • • chains with shared O, the structure is called a pyroxene formula unit Si. O 32 chains held together by ionic bonding to metal cations between the chains ü diopside = Ca. Mg(Si. O 3)2 where Ca and Mg occupy lattice points between the chains Tro, Chemistry: A Molecular Approach 12

Double Chain Silicates • some silicates have 2 • chains bonded together at ½ the tetrahedra – these are called amphiboles often results in fibrous minerals üasbestos ütremolite asbestos = Ca 2(OH)2 Mg 5(Si 4 O 11)2 Tro, Chemistry: A Molecular Approach 13

Sheet Silicates • when 3 O of each • • • tetrahedron are shared, the result is a sheet structure called a phyllosilicate formula unit = Si 2 O 52− sheets are ionically bonded to metal cations that lie between the sheets talc and mica Tro, Chemistry: A Molecular Approach 14

Mica: a Phyllosilicate Tro, Chemistry: A Molecular Approach 15

Silicate Structures Tro, Chemistry: A Molecular Approach 16

Boron • metalloid • at least 5 allotropes, whose structures are icosahedrons ü each allotrope connects the icosahedra in different ways • less than 0. 001% in Earth’s crust, but found concentrated in certain areas ü almost always found in compounds with O Ø borax = Na 2[B 4 O 5(OH)4] 8 H 2 O Ø kernite = Na 2[B 4 O 5(OH)4] 3 H 2 O Ø colemanite = Ca 2 B 6 O 11 5 H 2 O • used in glass manufacturing – borosilicate • glass = Pyrex used in control rods of nuclear reactors Tro, Chemistry: A Molecular Approach 17

Boron Trihalides • BX 3 • sp 2 B ütrigonal planar, 120 bond angles üforms single bonds that are shorter and stronger than sp 3 C üsome overlap of empty p on B with full p on halogen • strong Lewis Acids Tro, Chemistry: A Molecular Approach 18

Boron-Oxygen Compounds • form structures with trigonal • BO 3 units in B 2 O 3, six units are linked in a flat hexagonal B 6 O 6 ring ümelts at 450 C Ømelt dissolves many metal oxides and silicon oxides to form glasses of different compositions Tro, Chemistry: A Molecular Approach 19

Boranes closo-Boranes • compounds of B and H • used as reagent in hydrogenation of C=C • closo-Boranes have formula Bn. Hn 2− and form closed polyhedra with a BH unit at each vertex Tro, Chemistry: A Molecular Approach 20

Boranes nido-Boranes and arachno-Boranes • nido-Boranes have formula Bn. Hn+4 consisting of • cage B missing one corner arachno-Boranes have formula Bn. Hn+6 consisting of cage B missing two or three corners Tro, Chemistry: A Molecular Approach 21

Carbon • exhibits the most versatile bonding of all the • • elements diamond structure consists of tetrahedral sp 3 carbons in a 3 -dimensional array graphite structures consist of trigonal planar sp 2 carbons in a 2 -dimensional array üsheets 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 22

Crystalline Allotropes of Carbon Diamond Graphite Buckminsterfullerene, C 60 Color clear-blue black Density, g/cm 3 3. 53 2. 25 1. 65 Hardness, Mohs Scale 10 0. 5 Electrical Conductivity, (m • cm)-1 ~10 -11 7. 3 x 10 -4 Thermal Conductivity, W/cm • K 23 20 ( ) Melting Point, C ~3700 ~3800 sublimes Heat of Formation (kcal/mol) 0. 4 0. 0 9. 08 Refractive Index 2. 42 ─ 2. 2 (600 nm) Source Kimberlite (S. Africa) Pegmatite (Sri Lanka) Shungite (Russia) ~10 -14 23

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 24

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 25

Noncrystalline Forms of Carbon • coal is a mixture of hydrocarbons and carbon-rich particles ü the product of carbonation of ancient plant material Ø 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 ü carbon and ash • heating wood in the absence of air forms charcoal ü activated carbon is charcoal used to adsorb other molecules • soot is composed of hydrocarbons from incomplete combustion ü carbon black is finely divided form of carbon that is a component of soot Ø used as rubber strengthener Tro, Chemistry: A Molecular Approach 26

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 27

Nanotubes • long hollow tubes constructed of fused C 6 rings • electrical conductors • can incorporate metals and other small molecules and elements üused 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 28

Nanotubes Tro, Chemistry: A Molecular Approach 29

Nanocars Tro, Chemistry: A Molecular Approach 30

Carbides • carbides are binary compounds of C with a less electronegative • element ionic carbides are compounds of metals with C ü generally alkali or alkali earth metals ü often dicarbide ion, C 22− (aka acetylide ion) ü react with water to form acetylene, C 2 H 2 • covalent carbides are compounds of C with a lowelectronegativity nonmetal or metalloid ü silicon carbide, Si. C (aka carborundum) Ø very hard • metallic carbides are metals in which C sits in holes in the metal lattice ü hardens and strengthens the metal without affecting electrical conductivity ü steel and tungsten carbide Tro, Chemistry: A Molecular Approach 31

Calcium Carbide Tro, Chemistry: A Molecular Approach 32

Cementite Fe 3 C regions found in steel Tro, Chemistry: A Molecular Approach 33

Carbon Oxides • CO 2 ü 0. 04% in atmosphere Ø increased by 25% over the past century ü high solubility in water Ø due to reaction with water to form HCO 3− ions ü triple point − 57 C and 5. 1 atm • CO Ø liquid CO 2 doesn’t exist at atmospheric pressure Ø solid CO 2 = dry ice ü colorless, odorless, tasteless gas ü relatively reactive Ø 2 CO + O 2 2 CO 2 – burns with a blue flame Ø reduces many nonmetals – CO + Cl 2 COCl 2 (phosgene) – CO + S COS (fungicide) Tro, Chemistry: A Molecular Approach 34

Carbonates • solubility of CO 2 in H 2 O due to carbonate formation ü CO 2 + H 2 O H 2 CO 3 ü H 2 CO 3 + H 2 O H 3 O+ + HCO 3− ü HCO 3− + H 2 O H 3 O+ + CO 32− • washing soda = Na 2 CO 3 10 H 2 O ü doesn’t decompose on heating • all carbonate solutions are basic in water ü due to CO 32− + H 2 O OH− + HCO 32− • baking soda = Na. HCO 3 ü decomposes on heating to Na 2 CO 3, H 2 O and CO 2 Tro, Chemistry: A Molecular Approach 35

Elemental Nitrogen • N 2 ü 78% of atmosphere üpurified by distillation of liquid air, or filtering air through zeolites üvery stable, very unreactive ØN N Tro, Chemistry: A Molecular Approach 36

Elemental Phosphorus • P ü white phosphorus Ø white, soft, waxy solid that is flammable and toxic Ø stored under water to prevent spontaneous combustion Ø 2 Ca 3(PO 4)2 (apatite) + 6 Si. O 2 + 10 C P 4(g, wh) + 6 Ca. Si. O 3 + 10 CO Ø tetrahedron with small angles 60 ü red phosphorus Ø formed by heating white P to about 300 C in absence of air Ø amorphous Ø mostly linked tetrahedra Ø not as reactive or toxic as white P Ø used in match heads ü black phosphorus Ø formed by heating white P under pressure Ø most thermodynamically stable form, therefore least reactive Ø layered structure similar to graphite Tro, Chemistry: A Molecular Approach 37

Phosphorus White Red Phosphorus Tro, Chemistry: A Molecular Approach 38

Hydrides of Nitrogen • ammonia, NH 3 ü pungent gas ü basic NH 3 + H 2 O NH 4+ + OH− Ø reacts with acids to make NH 4+ salts – used as chemical fertilizers ü made by fixing N from N 2 using the Haber-Bosch process • hydrazine, N 2 H 4 ü colorless liquid ü basic N 2 H 4 + H 2 O N 2 H 5+ + OH− ü powerful reducing agent • hydrogen azide, HN 3 ü acidic HN 3 + H 2 O H 3 O+ + N 3− ü thermodynamically unstable and decomposes explosively to its elements Tro, Chemistry: A Molecular Approach 39

Hydrazine Tro, Chemistry: A Molecular Approach 40

Oxides of Nitrogen • formed by reaction of N 2 or NOx with O 2 • all unstable and will eventually decompose into N 2 and O 2 • NO = nitrogen monoxide = nitric oxide ü important in living systems ü free radical • NO 2 = nitrogen dioxide ü 2 NO 2 N 2 O 4 ü red-brown gas ü free radical • N 2 O = dinitrogen monoxide = nitrous oxide ü ü ü laughing gas made by heating ammonium nitrate NH 4 NO 3 N 2 O + H 2 O oxidizing agent Mg + N 2 O N 2 + Mg. O decomposes on heating 2 N 2 O 2 N 2 + O 2 pressurize food dispensers Tro, Chemistry: A Molecular Approach 41

Tro, Chemistry: A Molecular Approach 42

Nitric Acid • HNO 3 = nitric acid ü produced by the Ostwald Process 4 NH 3(g) + 5 O 2(g) 4 NO(g) + 6 H 2 O(g) 2 NO(g) + O 2(g) 2 NO 2(g) 3 NO 2(g) + H 2 O(l) 2 HNO 3(l) + NO(g) ü strong acid ü strong oxidizing agent ü concentrated = 70% by mass = 16 M Ø some HNO 3 in bottle reacts with H 2 O to form NO 2 ü main use to produce fertilizers and explosives NH 3(g) + HNO 3(aq) NH 4 NO 3(aq) Tro, Chemistry: A Molecular Approach 43

Nitrates and Nitrites • NO 3− = nitrate ü ANFO = ammonium nitrate fuel oil Ø used as explosive in Oklahoma City ü ammonium nitrate can decompose explosively Ø and other nitrates 2 NH 4 NO 3 2 N 2 + O 2 + 4 H 2 O ü metal nitrates used to give colors to fireworks ü very soluble in water ü oxidizing agent • NO 2− = nitrite ü Na. NO 2 used as food preservative in processed meats Ø kills botulism bacteria Ø keeps meat from browning when exposed to air Ø can form nitrosamines which may increase risk of colon cancer? ? Tro, Chemistry: A Molecular Approach 44

Phosphine • PH 3 ü colorless, poisonous gas that smells like rotting fish ü formed by reacting metal phosphides with water Ca 3 P 2(s) + 6 H 2 O(l) 2 PH 3(g) + 3 Ca(OH)2(aq) ü also by reaction of wh P with H 2 O in basic solution 2 P 4(s) + 9 H 2 O(l) + 3 OH−(aq) 5 PH 3(g) + 3 H 2 PO 4−(aq) ü decomposes on heating to elements 4 PH 3(g) P 4(s) + 6 H 2(g) ü reacts with acids to form PH 4+ ion ü does not form basic solutions Tro, Chemistry: A Molecular Approach 45

Phosphorus Halides • P 4 can react directly with halogens to form PX 3 and • PX 5 compounds PX 3 can react with water to form H 3 PO 3 ü PX 5 can react with water to form H 3 PO 4 PCl 3(l) + 3 H 2 O(l) H 3 PO 3(aq) + 3 HCl(aq) • PCl 3 reacts with O 2 to form POCl 3(l) ü phosphorus oxychloride ü other oxyhalides made by substitution on POCl 3 • phosphous halide and oxyhalides are key starting materials in the production of many P compounds ü fertilizers, pesticides, oil-additives, fire-retardants, surfactants Tro, Chemistry: A Molecular Approach 46

Phosphorus Oxides • P 4 reacts with O 2 to make P 4 O 6(s) or P 4 O 10(s) üget P 4 O 10 with excess O 2 Tro, Chemistry: A Molecular Approach 47

Phosphoric Acid and Phosphates • H 3 PO 4 = phosphoric acid üwhite solid that melts at 42 C üconcentrated = 85% by mass = 14. 7 M üproduced by reacting P 4 O 10 with water or the reaction of Ca 3(PO 4)2 with sulfuric acid P 4 O 10(s) + 6 H 2 O(l) 4 H 3 PO 4(aq) Ca 3(PO 4)2(s) + 3 H 2 SO 4(l) 3 Ca. SO 4(s) + 2 H 3 PO 4(qa) üused in rust removal, fertilizers, detergent additives and food preservative Øsodium pyrophosphate = Na 4 P 2 O 7 Øsodium tripolyphosphate = Na 5 P 3 O 10 Tro, Chemistry: A Molecular Approach 48

Use of Phosphates in Food Tro, Chemistry: A Molecular Approach 49

Oxygen • 2 s 22 p 4 ü 6 valence electrons • stronger oxidizing agent than other 6 A elements üused 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 50

Elemental Oxygen • O 2 ü nonpolar, colorless, odorless gas ü freezing point − 183 C at which it becomes a pale blue liquid ü slightly soluble in water Ø 0. 04 g/L ü mainly produced by fractional distillation of air Ø also by the electrolysis of water ü can be synthesized by heating metal oxides, chlorates, or nitrates Hg. O(s) Hg(l) + O 2(g) 2 Na. NO 3(s) 2 Na. NO 2(s) + O 2(g) 2 KCl. O 3(s) 2 KCl(s) + 3 O 2(g) ü used in high temperature combustion Ø blast furnace, oxyacetylene torch ü used to create artificial atmospheres Ø divers, high-altitude flight ü medical treatment Ø lung disease, hyperbaric O 2 to treat skin wounds Tro, Chemistry: A Molecular Approach 51

Oxides • reacts with most other elements to form oxides üboth metals and nonmetals • oxides containing O 2− with − 2 oxidation state • most stable for small ions with high charge oxides containing O 2− with −½ oxidation state most stable for large ions with smaller charge Tro, Chemistry: A Molecular Approach 52

Ozone • O 3 ü toxic, pungent, blue, diamagnetic gas ü denser than O 2 ü freezing point − 112 C, where it becomes a blue liquid ü synthesized naturally from O 2 through the activation by ultraviolet light Ø mainly in the stratosphere Ø protecting the living Earth from harmful UV rays ü spontaneously decomposes into O 2 ü commercial use as a strong oxidizing agent and disinfectant ü formed in the troposphere by interaction of UV light and auto exhaust Ø oxidation damages skin, lungs, eyes, and cracks plastics and rubbers Tro, Chemistry: A Molecular Approach 53

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 ü some on the surface • below ground recovered by the Frasch Process ü 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 Tro, Chemistry: A Molecular Approach 54

Natural Sulfur Deposit Tro, Chemistry: A Molecular Approach 55

Frasch Process Tro, Chemistry: A Molecular Approach 56

Allotropes of Sulfur • several crystalline forms • the most common naturally occurring allotrope has S 8 rings ü most others also ring structures of various sizes • when heated to 112 C, S 8 melts to a yellow liquid with low • viscosity when heated above 150 C, rings start breaking and a dark brown viscous liquid forms ü darkest at 180 C ü 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 57

sulfur at ~150 C Tro, Chemistry: A Molecular Approach sulfur at ~180 C 58

Amorphous Sulfur Tro, Chemistry: A Molecular Approach 59

Other Sources of Sulfur • H 2 S(g) from oil and natural gas deposits ü ü ü 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 H 2 S(g) + 2 O 2(g) 2 SO 2(g) + 2 H 2 O(g) 4 H 2 S(g) + 2 SO 2(g) 6 S(s) + 4 H 2 O(g) • Fe. S 2 (iron pyrite) ü roasted in absence of air forming Fe. S(s) and S 2(g) • metal sulfides ü ü roasted in air to make SO 2(g), which is later reduced react with acids to make H 2 S most insoluble in water used as bactericide and stop dandruff in shampoo Tro, Chemistry: A Molecular Approach 60

Metal Sulfides Tro, Chemistry: A Molecular Approach 61

• SO 2 Sulfur Dioxide ü colorless, dense, acrid gas that is toxic ü produced naturally by volcanic action and as a byproduct of industrial processes Ø including electrical generation by burning oil and coal, as well as metal extraction ü acidic SO 2(g) + H 2 O(l) H 2 SO 3(aq) ü forms acid rain in the air 2 SO 2(g) + 2 H 2 O(l) 2 H 2 SO 4(aq) ü removed from stack by scrubbing with limestone Ca. CO 3(s) Ca. O(s) + O 2(g) 2 Ca. O(g) + 2 SO 2(g) + O 2(g) 2 Ca. SO 4(g) ü used to treat fruits and vegetables as a preservative Tro, Chemistry: A Molecular Approach 62

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 ü oily, dense liquid at room temperature • reacts vigorously and exothermically with water ü “you always oughter(sic) add acid to water” Tro, Chemistry: A Molecular Approach 63

Dehydration of Sucrose C 12 H 22 O 11(s) + H 2 SO 4(l) 12 C(s) + 11 H 2 O(g) + H 2 SO 4(aq) Tro, Chemistry: A Molecular Approach 64

Production of H 2 SO 4 • contact process • step 1: combustion of elemental S ü complete using V 2 O 5 catalyst S(g) + O 2(g) SO 2(g) 2 SO 2(g) + O 2(g) 2 SO 3(g) • step 2: absorbing the SO 2 into conc. H 2 SO 4 to form oleum, H 2 S 2 O 7 SO 3(g) + H 2 SO 4(l) H 2 S 2 O 7(l) • step 3: dissolve the oleum in water H 2 S 2 O 7(l) + H 2 O(l) 2 H 2 SO 4(aq) Tro, Chemistry: A Molecular Approach 65

Halogens • most reactive nonmetal group, never found in elemental • form in nature come from dissolved salts in seawater ü except fluorine, which comes from minerals fluorospar (Ca. F 2) and fluoroapatite [Ca 10 F 2(PO 4)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 Tro, Chemistry: A Molecular Approach 66

Properties of the Halogens Tro, Chemistry: A Molecular Approach 67

Fluorine • F 2 is a yellow-green toxic gas • F 2 is the most reactive nonmetal and forms binary compounds with every element except He, Ne, and Ar ü including Xe. F 2, Xe. F 6, Xe. OF 4, Kr. F 2 ü so reactive it reacts with other elements of low reactivity resulting in flames ü even reacts with the very unreactive asbestos and glass Ø stored in Fe, Cu, or Ni containers because the metal fluoride that forms coats the surface protecting the rest of the metal • F 2 bond weakest of the X 2 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 68

Hydrofluoric Acid • HF ü produced by the reaction of fluorospar with H 2 SO 4 Ca. F 2(s) + H 2 SO 4(l) Ca. SO 4(s) + 2 HF(g) ü crystalline HF is zig-zag chains ü HF is weak acid, Ka = 6. 8 x 10 -4 at 25 C ü F− can combine with HF to form complex ion HF 2− Ø with bridging H ü strong oxidizing agent Ø strong enough to react with glass, so generally stored in plastic Ø used to etch glass Si. O 2(g) + 4 HF(aq) Si. F 4(g) + H 2 O(l) ü very toxic because it penetrates tissues and reacts with internal organs and bones Tro, Chemistry: A Molecular Approach 69

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 ü for interhalides, the larger has lower electronegativity – so it is central in the molecule; with a number of more electronegative halides attached ü general formula ABn where n can be 1, 3, 5, or 7 Ø most common AB or AB 3; only AB 5 has B = F, IF 7 only known n = 7 ü only Cl. F 3 used industrially Ø to produce UF 6 in nuclear fuel enrichment • most halogen oxides are unstable ü tend to be explosive ü OF 2 only compound with O = +2 oxidation state ü Cl. O 2(g) is strong oxidizer used to bleach flour and wood pulp Ø explosive – so diluted with CO 2 and N 2 Ø produced by oxidation of Na. Cl. O 2 with Cl 2 or the reduction of Na. Cl. O 3 with HCl 2 Na. Cl. O 2 + Cl 2 2 Na. Cl + 2 Cl. O 2 2 Na. Cl. O 3 + 4 HCl 2 Cl. O 2 + 2 H 2 O + 2 Na. Cl Tro, Chemistry: A Molecular Approach 70