gc-s010-nomenclature

Henry R. Kang (1/2010)

General Chemistry

Lecture 10

Nomenclature of Chemical Compounds

Contents

• Naming Ionic Compounds

• Naming Molecular Compounds

• Naming Simple Acids

• Naming Oxoacids

• Naming Bases

• Common Names

• Introduction to Organic Compounds Naming simple organic compounds


Types of Chemical Compounds

• Inorganic Compounds Ionic compounds Molecular compounds Acids and bases Hydrates

• Organic Compounds Compounds contain carbon in combination

with other elements such as hydrogen, oxygen, nitrogen, sulfur, phosphorus, fluorine or chlorine.


Naming

Ionic Compounds


Naming of Binary Ionic Compounds

• Binary ionic compounds are formed from two elements. Often a metal (to form cation) + a nonmetal (to form anion)

• The metal cation is named first, followed by the nonmetallic anion with “-ide” ending. The cation is named by using the name of the element. The anion is named by taking the name of the element, then

replacing its ending with “ide”. Examples:

“bromine”, the ending “ine” is replaced by “ide” to become “bromide”

“oxygen”, the ending “ygen” is replaced by “ide” to become “oxide”.


Common Monoatomic Cations• Monoatomic cations

Group 1A: Hydrogen (H+), Lithium (Li+), Potassium (K+), Sodium (Na+).

Group 2A: Barium (Ba2+), Calcium (Ca2+), Magnesium (Mg2+).

Group 3A: Aluminum (Al3+), Gallium (Ga3+).

Group 4A: Lead(II) or plumbous (Pb2+), Tin(II) or stannous (Sn2+).

• Transition metals:

Group 1B: Copper(I) or cuprous (Cu+), Copper(II) or cupric (Cu2+), Silver (Ag+).

Group 2B: Mercury(II) or mercuric (Hg2+), Zinc (Zn2+).

Group 6B: Chromium(III) or chromic (Cr3+),

Group 7B: Manganese(II) or manganous (Mn2+),

Group 8B: Iron(II) or ferrous (Fe2+), Iron(III) or ferric (Fe3+),


Common Monoatomic AnionsGroup Element Stem Name in

Compound

1A H: hydrogen Hydr- H−: hydride

F: flourine Fluor- F−: fluoride

7A Cl: chlorine Chlor- Cl−: chloride

Br: bromine Brom- Br−: bromide

I: iodine Iod- I−: iodide

6A O: oxygen Ox- O2−: oxide

S: sulfur Sulf- S2−: sulfide

5A N: nitrogen Nitr- N3−: nitride

P: phosphorous Phosph- P3−: phosphide

4A C: carbon Carb- C4−: carbideHenry R. Kang (1/2010)

Examples of Naming Binary Compounds

• Name the following compounds: NaF: sodium fluoride, KBr: potassium bromide,

ZnI2: zinc iodide,

Al2O3: aluminum oxide,

BaCl2: barium chloride,

K2O: potassium oxide

• Write chemical formulas for the following compounds: Silver bromide: AgBr

Aluminum chloride: AlCl3

Sodium sulfide: Na2S

Magnesium hydride: MgH2 Henry R. Kang (1/2012)

Elements form Cations with Different Charges

• Transition metal elements (in Groups 1B and 3B to 8B) and heavy metal elements (in Groups 3A and 4A) can form more than one type of cations.

• Examples: Transition elements: Fe2+ and Fe3+; Cu+ and Cu2+; Mn2+, Mn3+, and Mn4+

Group 3A: Tl+ and Tl3+

Group 4A: Pb2+ and Pb4+

3

37

19

11

55

20

10

3231 36353433

15 16 17 18

42

14

38 41

57

4039

56

49 50 51 52 53 54

7372 74

43 44 45 46 47 48

76 79 83 84 85 8675 80Hg2

2+

Hg2+

78 81Tl+

Tl3+

77 82Pb2+

Pb4+

4

1

9

2

5 6 7 8

55B

44B

66B

33B

88B

77B

98B

108B

111B

122B

30

1312

24Cr3+

232221 29Cu+

Cu2+

28Ni2+

27Co2+

Co3+

26Fe2+

Fe3+

25Mn2+

Mn4+


Naming Ions with Different Charges

• Old System Use the ending “-ous” for cation with few positive

charges.Fe2+: ferrous; Cu+: cuprous

Use the ending “-ic” for cation with more positive charges.Fe3+: ferric; Cu2+: cupric

• New System (Stock system) Designate different cations with Roman numerals to

indicate the number of charges.


Examples of Naming Metal Ions with Different Charges

ChargeOne

positive charge

Twopositive charges

Threepositive charges

Fourpositive charges

Fivepositive charges

Sixpositive charges

Roman numeral

I II III IV V VI

Examples

Cu+(Cu2O)copper(I)

Cu2+(CuO)copper(II)

W6+(WO3)tungsten(VI)

Cr2+(CrS)chromium(II)

Cr3+(Cr2S3)chromium(III)

Fe2+(FeCl2)iron(II)

Fe3+(FeCl3)iron(III)

Mn2+(MnO)manganese(II)

Mn3+(Mn2O3) manganese(III)

Mn4+(MnO2)manganese(IV)

Sn2+(SnS)Tin(II)

Sn4+(SnS2)Tin(IV)

V2+(VCl2)vanadium (II)

V3+(VCl3)vanadium (III)

V5+(V2O5)vanadium(V)


Examples of Naming Metal Compounds with Different Charges

• FeCl2 : Iron(II) chloride

• FeCl3 : Iron(III) chloride

• CrS : Chromium(II) sulfide

• Cr2S3 : Chromium(III) sulfide

• MnO : Manganese(II) oxide

• Mn2O3 : Manganese(III) oxide

• MnO2 : Manganese(IV) oxide

• Lead(IV) oxide : PbO2

• Lead(II) oxide : PbO

• Tin(II) sulfide : SnS

• Tin(IV) sulfide : SnS2


Naming of Ionic Polyatomic Compounds

• Polyatomic Compounds are ionic compounds that consist of three or more elements. The metal cation is named first, followed by the name

of the polyatomic anion.

• Examples:

Mg(OH)2: magnesium hydroxide,

KCN: potassium cyanide,

Li2CO3: lithium carbonate,

KNO3: potassium nitrate.


Polyatomic Ions

• Polyatomic ions contain two or more atoms chemically bounded together with a net positive or negative charge for the whole group of atoms. The charge of a polyatomic ion can be derived

from the parent ionic compound.

Example:Na2SO4, the Na+ ion has one positive charge; thus, SO4 must

has 2 negative charges to neutralize the two positive charges.


Some Common Polyatomic Anions and CationsAnion (One negative charge) Formula Anion (Two negative charges) Formula

Acetate CH3COO– Carbonate CO32–

Chlorate ClO3– Chromate CrO4

2–

Chlorite ClO2– Dichromate Cr2O7

2–

Cyanide CN– Hydrogen phosphate (biphosphate) HPO42–

Dihydrogen phosphate H2PO4– Oxalate C2O4

2–

Hydrogen carbonate (bicarbonate) HCO3– Peroxide O2

2–

Hydrogen oxalate HC2O4– Sulfate SO4

2–

Hydrogen sulfate (bisulfate) HSO4– Sulfite SO3

2–

Hydrogen sulfite (bisulfite) HSO3– Silicate SiO3

2–

Hydrogen sulfide HS– Anion (Three negative charges)

Hydroxide OH– Arsenate AsO43–

Hypochlorite ClO– Borate BO33–

Nitrate NO3– Phosphate PO4

3–

Nitrite NO2– Phosphite PO3

3–

Perchlorate ClO4– Cation

Permanganate MnO4– Ammonium NH4

+

Thiocyanate SCN– Mercurous [or Mercury(I)] Hg22+Henry R. Kang (1/2010)

Formula of Ionic Compounds Containing Polyatomic Ions

• The sum of the charges on the cation(s) and anion(s) in each formula unit must be zero. If the charges on the cation and anion are

numerically different, then the subscript of the cation is equal to

the charge on the anion and the subscript of the anion is equal to

the charge on the cation. The subscripts must always be reduced to

the smallest ratios (Namely, the formula unit).

Na2SO4

Na+ SO42−

2×(+1) = +21×(-2) = -2

Sum = 0

Al(HCO3)3

Al3+ HCO3−

1×(+3) = +33×(-1) = -3

Sum = 0

Fe2(CO3)3

Fe3+ CO32−

2×(+3) = +6 3×(-2) = -6Sum = 0


Examples of Naming Polyatomic Compounds

• Name the following polyatomic ionic compounds:

Formula Name

CuNO3 Copper(I) nitrate

Ca3(PO4)2 Calcium phosphate

Fe2(CO3)3 Iron(III) carbonate

AgClO3 Silver chlorate

Li2SO3 Lithium sulfite

ZnSO4 Zinc sulfate

Mg(CN)2 Magnesium cyanideHenry R. Kang (1/2010)

Naming

Simple Molecular Compounds


Nomenclature of Covalent Compounds• Molecular compounds contain nonmetals or

(nonmetals + metalloids)• Last element ends in “ide”.

• Element left in periodic table is named first.• Example: HF, hydrogen fluoride

• Element closest to bottom of group is named first.• Example: SO2, sulfur dioxide

• If more than one compound can be formed from the same elements, use prefixes to indicate the number of each kind of atom.• NO: nitrogen monoxide

• NO2: nitrogen dioxide

• N2O: dinitrogen monoxide

• N2O4: dinitrogen tetraoxide

• N2O5: dinitrogen pentoxide

Prefix Number

Mono- 1

Di- 2

Tri- 3

Tetra- 4

Penta- 5

Hexa- 6

Hepta- 7

Octa- 8

Nona- 9

Deca- 10

Greek Prefixes


Examples of Naming Molecular Compounds• Name the following molecular compounds:

HI: hydrogen iodide

NF3: nitrogen trifluoride

SiCl4: silicon tetrachloride

N2Cl4: dinitrogen tetrachloride

SO2: sulfur dioxide

SO3: sulfur trioxide

NO2: nitrogen dioxide (Smog gas: Toxic!)

N2O: dinitrogen monoxide (Laughing gas) Note that the “o” is omitted in “mono”

P4O10: tetraphosphorus decoxide Note that the “a” is omitted in “deca”

Cl2O7: dichlorine heptoxide Note that the “a” is omitted in “hepta”


Examples of Writing Molecular Formulas

• Write chemical formulas for the following molecular compounds: Carbon disulfide

CS2

Disilicon hexabromideSi2Br6

Sulfur tetrafluorideSF4

Dinitrogen pentoxideNote that the “a” is omitted in “penta”

N2O5Henry R. Kang (1/2010)

Nomenclature of Inorganic Compounds

Ionic Compound

Molecular Compound

Cation: metal or NH4

+

Anion: mono- or polyatomic

Binary compounds of nonmetals

Cation has only one charge value (Alkali metal cations, Alkaline earth metal ions, Ag+, Al3+, Cd2+, and Zn2+)

Cation has more than one charge value with different anion (All other metal cations.)

Use prefixes for both elements.(Prefix “mono-” usually is omitted for the first element).Add -ide to the root of the second element.

Name metal first.For monoatomic anion, add -ide to the root of the element.For polyatomic anion, use name of the anion.

Name metal first. For elements can form different cations, specify charge with Roman numeral in parentheses.For monoatomic anion, add -ide to the root of the element.For polyatomic anion, use the name of the anion.

Binary acids

Prefix hydro- and add the suffix -ic acid.

Inorganic Compound


NamingSimple Acids,

Oxoacids, and

Simple Bases


Simple Acids• A simple acid is a compound that yields hydrogen ions (H+) when

dissolved in water. It consists H element and a nonmetal element (or a polyatomic anion).

• Simple acids are named by adding prefix “hydro-” to the name of the nonmetal element and replacing the ending with the suffix “-ic acid”.

• Some anions and corresponding acids.

Anion Acid Acid Name Molecular Name

F- (fluoride) HF(aq) Hydrofluoric acid HF(g): Hydrogen fluoride

Cl- (chloride) HCl(aq) Hydrochloric acid HCl(g): Hydrogen chloride

Br- (bromide) HBr(aq) Hydrobromic acid HBr(l): Hydrogen bromide

I- (iodide) HI(aq) Hydroiodic acid HI(s): Hydrogen iodide

CN- (cyanide) HCN(aq) Hydrocyanic acid HCN(g): Hydrogen cyanide

S2- (sulfide) H2S(aq) Hydrosulfuric acid H2S(g): Hydrogen sulfide



Oxoacids• Oxoacids are acids that contain hydrogen, oxygen, and another

element (the central element) Usually, the H goes first, followed by the central element, then O.

• Oxoanion is the anion of the oxoacid that hydrogen ions have been removed.

• Some common oxoacids and oxoanions:

Oxoacid Name Oxoacid Formula Oxoanion Formula Oxoanion Name

Nitric acid HNO3 NO3− Nitrate

Chloric acid HClO3 ClO3− Chlorate

Carbonic acid H2CO3 CO32− Carbonate

Sulfuric acid H2SO4 SO42− Sulfate

Phosphoric acid H3PO4 PO43− Phosphate

This set of oxoacids are considered as the reference acids.


Family of Oxoacid

• An oxoacid forms a family of acids by successively decreasing O atom form the reference acid and in some cases to form acid by increasing O atom to the reference acid.

• Examples:

HClO3:Reference acid

HClO2:One less O atom than the reference

HClO: Two less O atoms than the reference

HClO4:One more O atom than the reference


Naming Family of Oxoacids & Oxoanions• The naming of a family of oxoacids and oxoanions is derived from

the reference acid.• Oxoacids

The reference acid: Replace the ending of the central atom by “ic acid”.

For one more O atom: Add prefix “per” to the name of the reference acid.

For one less O atom: Replace “ic” of the reference acid with “ous”.

For two less O atoms: Replace “ic” with “ous” and add prefix “hypo” to the name of the reference acid.

• Oxoanions The reference oxoanion: Replace the ending “ic acid” with “ate”.

For one more O atom: Keep the prefix “per” and replace the ending “ic acid” with “ate”.

For one less O atom: Replace “ous acid” with “ite”.

For two less O atoms: Keep the prefix “hypo” and replace “ous acid” with “ite”.

Naming Oxoacid and Oxoanion: HNO3

Oxoacid Oxoanion

Example ExampleRepresentative

“-ic” acid

“-ous” acid

“hypo-” “-ous” acid

“-ate”

“-ite”

“hypo-” “-ite”

HNO3

nitric acid

HNO2

nitrous acid

HNOhyponitrous acid

Removal of all H ions

NO3−

nitate

NO2−

nitrite

NO−

hyponitrite

-[O]

-[O]

Reference acid


Naming Oxoacid & Oxoanion: H2SO4

Oxoacid OxoanionExample Example

Representative“-ic” acid

“-ous” acid


“-ate”

“-ite”


H2SO4

sulfuric acid

H2SO3

sulfurous acid

H2SO2

hyposulfurous acid


SO42−

sulfate

SO32−

sulfite

SO22−

hyposulfite

-[O]

-[O]

Reference acid


Naming Oxoacids & Oxoanions: H3PO4

Oxoacid Oxoanion

Example Example


“-ous” acid


“-ate”

“-ite”


H3PO4

H3PO3

phosphoric acid

H3PO2

phosphorous acid

hypophosphorous acid

PO43−


PO33−

phosphate

PO23−

phosphite

hypophosphite

-[O]

-[O]

Reference acid



Naming Oxoacids & Oxoanion: HBrO3

Example Example

“per-” “-ic” acid


“-ous” acid


“per-” “-ate”

“-ate”

“-ite”


HBrO4

perbromic acid

HBrO3

bromic acid

HBrO2

bromous acid

HBrOhypobromou

s acid

BrO4−

perbromate

BrO3 −

bromate

BrO2 −

bromite

BrO −

hypobromite

+[O]

-[O]

-[O]

Reference acid


Examples of Naming Oxoacids & Salts

• Name the following oxoacid, oxoanion, and salts: H3PO3: Phosphorous acid

One fewer O than the reference phosphoric acid (H3PO4)

IO4-: Periodate

One more O than the reference iodic acid (HIO3).

HBrO: Hypobromous acid Two fewer O atoms than the reference bromic acid (HBrO3).

HSO4-: Hydrogen sulfate ion

Cu(NO3)2: Copper(II) nitrate [Stock system]

KH2PO4: Potassium dihydrogen phosphate

NH4ClO3: Ammonium chlorate

Li2SO3: Lithium sulfite (one less O than the reference)


Examples of Formulas of Oxo-Salts

• Write chemical formulas for the following compounds:

Mercury(I) nitrite: Hg2(NO2)2

Note that mercury(I) ion exists as a diatomic ion (Hg22+)

Rubidium sulfate: Rb2SO4

Cadmium carbonate: CdCO3

Nickel(II) nitrate: Ni(NO3)2

Calcium phosphate: Ca3(PO4)2

Chromium(II) chlorate: Cr(ClO3)2

Lead(IV) sulfate: Pb(SO4)2


Simple Bases

• A simple base is a substance that yields hydroxide ions (OH–) when dissolved in water.

• Naming Bases Bases are named by the name of the metal cation first,

followed by the word “hydroxide”.

• Examples: NaOH: sodium hydroxide KOH: potassium hydroxide

Ba(OH)2: barium hydroxide

NH3: ammonia (ammonia hydroxide?)

NH3 + H2O NH4+ + OH–

Hydrates

• Hydrates are compounds that have a specific number of water molecules attached to them.

• Naming Hydrates Hydrates are named by naming the salt first, followed by the

word “hydrate” with “prefix” to indicate the number of water molecules.

• Examples: BaCl2.2H2O: barium chloride dihydrate

LiCl.H2O: lithium chloride monohydrate

MgSO4.7H2O: magnesium sulfate heptahydrate

CuSO4.5H2O: copper(II) sulfate pentahydrate

CuSO4.5H2O is blue crystal-like compound, while CuSO4 is a white powder-like compound. Henry R. Kang (1/2010)

Common Names

Formula Common Name Systematic Name

H2O Water Dihydrogen monoxide

H2S Hydrogen sulfide Dihydrogen monsulfide

NH3 Ammonia Trihydrogen nitride

PH3 Phosphine Trihydrogen phoside

CO2(s) Dry ice Carbon dioxide (solid)

NaCl Table salt Sodium chloride

N2O Laughing gas Dinitrogen monoxide

NaHCO3 Baking soda Sodium hydrogen carbonate

CH4 Methane Carbon tetrahydride

SiH4 Silane Silicon tetrahydride

Frequently encountered molecular compounds often have common names.


Introductionof

Organic Compounds


Organic Compounds• Organic compounds contain carbon in combination with

other elements such as hydrogen, oxygen, nitrogen, sulfur, phosphorus, fluorine or chlorine.

Most, if not all, organic compounds are covalent compounds.

• The chemical characteristics and properties of organic compounds are largely determined by the functional groups.

• Major functional groups: Hydroxyl group (-OH); example: Ethanol, C2H5OH

Amino group (-NH2); example: Methylamine, CH3NH2

Carbonyl group (C=O); example: Formaldehyde, H2C=O

Carboxyl group (-COOH); example: Acetic acid, CH3COOHHenry R. Kang (1/2010)

Name & Formula of First 10 Alkanes• Methane, CH4

• Ethane, C2H6 (CH3CH3)

• Propane, C3H8 (CH3CH2CH3)

• Butane, C4H10 (CH3CH2CH2CH3)

• Pentane, C5H12 (CH3CH2CH2CH2CH3)

• Hexane, C6H14 (CH3CH2CH2CH2CH2CH3)

• Heptane, C7H16 (CH3CH2CH2CH2CH2CH2CH3)

• Octane, C8H18 (CH3CH2CH2CH2CH2CH2CH2CH3)

• Nonane, C9H20

(CH3CH2CH2CH2CH2CH2CH2CH2CH3)

• Decane, C10H22

(CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3)

Prefix Meaning

Mono- 1

Di- 2

Tri- 3

Tetra- 4

Penta- 5

Hexa- 6

Hepta- 7

Octa- 8

Nona- 9

Deca- 10


gc-s010-nomenclature

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