~ 1 ~

Binary Compounds are made up of only two

elements. They have three different naming

patterns, each with its own rules:

Binary Covalent (BC): any two non-metals

Binary Acids (BA): Hydrogen + Halogen

Ionic (I): Metal + Non-metal

For each of the following examples, identify the

naming system which would apply: BC, BA, or I.

Ex.1) HF Na2S CrO

Ex.2) NaBr FeCl2 SO

Ex.3) OF2 HCl H2O

Ex.4) GaN NH3 Li2Se

6.1.1 Binary Naming Systems

~ 2 ~

Polyatomic compounds contain 3 or more elements

and also make up 3 unique naming systems:

Polyatomic (P): 3+ atoms, not acid/hydrate

Polyatomic Acid (PA): 3+ atoms, starts w/ H.

Hydrate (H): contains water (•H2O)

Identify each of the following as P or PA:

Ex.1) Na3PO4 HNO3 LiC2H3O2

Ex.2) H2SO4 HClO3 (NH4)2Cr2O7

Hydrates consist of a compound with attached water

molecule(s). They'll be classified twice: once as a

hydrate, and again for the compound to which those

waters are attached:

6.1.2 Polyatomic Naming Systems

~ 3 ~

Example: CaCl2 • 2 H2O I / H

(Ionic) Hydrate

Ex.3) HClO4•4H2O CaCO3•6H2O CoF2•4H2O

Ex.4) NH4NO3•3H2O NaF•H2O Zn(ClO4)2•12H2O

Now that you've learned all 6 naming systems: label

each of the following as BC, BA, I, P, PA, or H/?:

Ex.5) HBr Li3PO4 Fe2O3

Ex.6) PbBr4 HC2H3O2 HCl•5H2O

Ex.7) SF6 NH4Cl AlI3

Ex.8) MgSO4•8H2O CrO3 NaOH

~ 4 ~

When a single non-metal such as O, F, or Cl appears

at the end of a chemical formula, its name changes

into a new format. The first portion of its name,

called the stem, is kept and then followed by -ide.

This is used to show that a non-metal has become

negatively-charged as a result of its chemical bond:

Chlorine → Chloride

( Cl ) ( Cl- )

A non-metal's name stem usually consists of the first

syllable. This is followed by the suffix -ide. Convert

each of the following into their -ide forms and show

the corresponding change in charge:

Ex.1) boron → sulfur →

( B ) ( ) ( S ) ( )

Ex.2) fluorine → bromine →

( F ) ( ) ( Br ) ( )

6.1.3 Stems, and -ide

~ 5 ~

Ex.3) oxygen → carbon →

( O ) ( ) ( C ) ( )

Ex.4) nitrogen → hydrogen →

( N ) ( ) ( H ) ( )

Some elements have longer, more complex stems,

keeping two or more syllables instead of just one:

Ex.5) phosphorus → iodine →

( P ) ( ) ( I ) ( )

Ex.6) selenium → arsenic →

( Se ) ( ) ( As ) ( )

Ex.7) tellurium → astatine →

( Te ) ( ) ( At ) ( )

*Note: -ium or -um usually indicates a (+) charge.

Notice that this is true for almost all of the metals.

~ 6 ~

Binary covalent formulas consist of two non-metals

and follow the general naming pattern shown below.

Prefix-name followed by prefix+stem-ide.

S2Cl5 → di + sulfur penta + chlor + ide

2 S 5 Cl

Prefixes are used to indicate the number of each

element in a binary covalent formula. You need to

memorize and practice these - make flashcards!

1 Mono - 5 Penta - 9 Nona -

2 Di - 6 Hexa - 10 Deca -

3 Tri - 7 Hepta - 11 Undeca -

4 Tetra - 8 Octa - 12 Dodeca -

Write a BC name in order, using prefixes at the front

of each element name to indicate its amount.

Convert the second name into -ide form:

6.2.1 Naming Binary Covalent Compounds

~ 7 ~

S3Cl4 → trisulfur tetrachloride

Ex.1) S3F7 →

Ex.2) C5H12 →

Ex.3) P6O3 →

Ex.4) B2N8 →

Ex.5) N9F11 →

mono- is never used on the first element, but CAN be

used for the second element:

CO monocarbon monoxide → carbon monoxide

Ex.6) BrF →

Ex.7) NCl3 →

Ex.8) P2S →

~ 8 ~

Drop the "a" or "o" at the end of a prefix if the

element name begins with an "a" or "o".

Combinations of "i" with "a" and "o" are fine:

tetra + oxide = tetroxide, NOT tetraoxide

mono + oxide = monoxide, NOT monooxide

Ex.10) C3O6 →

Ex.11) SiAs →

Ex.12) NI3 →

Mixed Practice with binary covalent naming:

Ex.13) SO2 →

Ex.14) C3H6 →

Ex.15) Cl2C →

Ex.16) BF3 →

~ 9 ~

Covalent names are easily recognized due to their

prefixes. To construct a BC formula, underline the

prefixes and note their meaning. Then, identify the

numbers involved and place subscripts:

2 H 1 O

dihydrogen monoxide → H2O1 → H2O

(The number "1" is never left as a subscript. The

symbol implies the presence of at least one already.)

Name each of the following BC compounds:

Ex.1) tetrasulfur heptabromide →

Ex.2) tricarbon octahydride →

Ex.3) pentarsenic nonoxide →

Ex.4) diphosphorus monoiodide →

Ex.5) hexoxygen tetrafluoride →

6.2.2 Building Binary Covalent Formulas

~ 10 ~

No prefix on the first name = "1". The second half

of a BC name will always have a prefix:

Ex.6) carbon dioxide →

Ex.7) carbon monoxide →

Ex.8) sulfur hexafluoride →

Mixed practice with binary covalent formulas:

Ex.9) chlorine monoiodide →

Ex.10) undecasulfur hexanitride →

Ex.11) carbon tetrafluoride →

Ex.12) dicarbon octoxide →

Ex.13) pentacarbon dodecahydride →

Ex.14) silicon tetrabromide →

~ 11 ~

Metals (elements to the left of the staircase) are

named differently depending on whether they have

consistent, predictable charges or if they have

multiple possible charges:

Group 1, 2, and 13 metals have consistent charges

which are predicted through their VE: 1+ / 2+ / 3+

Almost all others are known as transition metals

and have the ability to assume multiple charges. To

avoid confusion, their charges are given as part of

their names using a roman numeral:

( I ) = One ( V ) = Five

( II ) = Two ( VI ) = Six

( III ) = Three ( VII ) = Seven

( IV ) = Four ( VIII ) = Eight

*Note: roman numerals 1-8 use the capital letters

"I" and "V".

6.3.1 Naming Metals and Transition Metals

~ 12 ~

Name each of the following. Use roman numerals to

indicate the charge of transition metals:

Li+ = lithium Pb4+ = lead (IV)

Ex.1) Ir6+ = Mg2+ =

Ex.2) Fe3+ = U8+ =

Ex.3) Po5+ = Al3+ =

Ex.4) Na+ = Co6+ =

Silver and zinc are exceptions and do not require

roman numerals. Silver is 1+, zinc is 2+:

Ex.5) Cu+ = Cu2+ =

Ex.6) Ag+ = Sr2+ =

Ex.7) Cr3+ = Zn2+ =

~ 13 ~

The formulas for all compounds which are not

binary covalent are assembled according to charges

in a process known as "swap and drop":

To "build" an ionic formula, you place the metal

in front of the non-metal, determine the charges on

BOTH, and "swap/drop" those charges. The total

positive charge (electrons being given) should match

the total negative charge (electrons being taken):

sodium oxide = Na+ O2- = Na2O

Ex.1) calcium phosphide = Ca2+ P3- =

Ex.2) copper (I) sulfide = Cu S =

Ex.3) cesium hydride = =

Ex.4) manganese (IV) chloride =

6.3.2 Building Ionic Formulas

~ 14 ~

Occasionally, you will be able to "simplify" a

formula if all the subscripts have a common divisor.

vanadium (II) oxide = V2+ O2- = VO

Ex.5) chromium (VI) nitride = Cr6+ N3- =

Ex.6) aluminum arsenide = Al As =

Ex.7) lead (IV) oxide = =

Ex.8) calcium sulfide = =

Mixed practice: convert each of the following ionic

names into formulas using "swap and drop":

Ex.9) barium silicide = =

Ex.10) iron (II) fluoride = =

Ex.11) calcium phosphide = =

~ 15 ~

Ex.12) aluminum chloride = =

Ex.13) chromium (III) silicide = =

Ex.14) beryllium nitride = =

Ex.15) plutonium (VIII) sulfide = =

Ex.16) magnesium oxide = =

Ex.17) gallium arsenide = =

Ex.18) copper (I) phosphide = =

~ 16 ~

Pattern: Metal Name Non-Metal Stem + ide

Na3N → Na3 N1 → Na+ N3-

= sodium nitride

VF3 → V1 F3 → V3+ F-

= vanadium (III) fluoride

*Note: Ionic names follow the same pattern as

binary covalent, but without the prefixes.

Writing ionic names with non-transition metals is

easy. Metal name + stem-ide

Ex.1) Li2O = lithium

Ex.2) Mg3N2 =

6.3.3 Naming Ionic Compounds

~ 17 ~

Ex.3) Be3P2 =

Ex.4) Ga2Se3 =

Ex.5) KI =

You must know the charge of a transition metal in

order to name it. Knowing the charge of the non-

metal, we can SOLVE for the charge of the metal. I

use "x" to represent the charge of the metal:

x 2-

Cr2O3 → Chromium (III) oxide

2x = 6+ x = 3+

Ex.6) ReO → rhenium ( ) oxide

Ex.7) Ni3N → nickel ( ) nitride

Ex.8) YO4 →

~ 18 ~

Ex.9) IrCl2 →

Ex.10) Pu4Si →

Ex.11) FeS →

Ex.12) MnO2 →

Mixed Practice - watch out for transition metals!

Ex.13) TiO3 =

Ex.14) SrCl2 =

Ex.15) Ag2S =

Ex.16) Zr3P =

~ 19 ~

Polyatomics are large groups of elements with a

charge. Think of them as groups of elements which

"hunt" in packs. You can find a list of polyatomics

and their charges on your formula charts and in

the reference materials attached to these notes.

Polyatomic ions are easily recognizeable as they

usually end in -ate or -ite. Be careful!

Chlorine = Cl Chloride = Cl-

Chlorite = ClO2-

Chlorate = ClO3-

There are 3 notable exceptions. Memorize them!

Hydroxide = OH- Cyanide = CN

-

Ammonium = NH4

+

6.4.1 Building Polyatomic Formulas

~ 20 ~

Polyatomics are assembled via "swap and drop".

Put the polyatomic in parentheses with the charge

outside and treat it as one big charged "lump" of

atoms. Parentheses are NOT required after

swapping if multiplying by 1.

sodium nitrate → Na+ (NO3)- → NaNO3

Ex.1) aluminum hydroxide → Al3+ (OH)- →

Ex.2) ammonium sulfide → (NH4)+ S →

Ex.3) barium chlorite → Ba ClO2 →

Ex.4) iron (I) sulfate → →

Ex.5) silver chromate → →

Ex.6) lead (IV) permanganate → →

Ex.7) magnesium cyanide → →

~ 21 ~

Ex.8) ammonium hydroxide → →

Simplification applies any time you use swap and

drop. Don't change anything inside the parentheses:

lead (II) sulfite = Pb2+ (SO3) 2- = PbSO3

Ex.9) magnesium carbonate = Mg2+ (CO3)2-

=

Ex.10) lead (IV) sulfate = Pb SO4 =

Ex.11) barium chromate = =

Ex.12) gold (VI) phosphate = =

Assorted Practice:

Ex.13) zinc sulfite = =

Ex.14) ammonium phosphide = =

Ex.15) gold (VI) hydroxide = =

~ 22 ~

Polyatomics follow the same pattern as ionic names,

but you do NOT modify the name of the poly ion:

LiC2H3O2 = lithium acetate

NH4Cl = ammonium chloride

Pb(ClO3)4 = lead (IV) chlorate

Polyatomic names are not changed or modified,

name other substances as per usual. Except for

ammonium (NH4+) polys generally appear at the end

of the formula:

Mg3(PO4)2 = magnesium phosphate

Ex.1) LiNO2 =

Ex.2) Al(ClO3)3 =

Ex.3) Al(ClO)3 =

6.4.2 Naming Polyatomic Compounds

~ 23 ~

Ex.4) NH4NO3 =

Ex.5) (NH4)2S =

Transition metals with polys involve a bit of math.

Use the KNOWN charge of the poly to solve for the

UNKNOWN charge of the transition metal:

x 2-

Cr2(SO4) → Chromium (I) sulfate

2x = 2+ x = 1+

Ex.6) Ni3(PO4)2 → nickel ( ) phosphate

Ex.7) Cu(MnO4)2 →

Ex.8) Pt(ClO4)6 →

Ex.10) V(Cr2O7)2 →

~ 24 ~

If the poly doesn't have parentheses, write them in.

Avoid mistakes with the poly's own subscripts!

Ex.11) FePO4 →

Ex.12) CoHCO3 →

Ex.13) Cu2SO3 →

Assorted Practice:

Ex.14) Na3PO4 →

Ex.15) Ti(NO3)3 →

Ex.16) MnC2H3O2 →

Ex.17) (NH4)2SO3 →

~ 25 ~

Binary (BA) hydro + stem + ic acid

hydrochloric acid

Polyatomic (PA) polyatomic stem + ic/ous acid

nitric acid / nitrous acid

*Note: H-Halogen and H-Poly are named as acids,

most others are covalent.

Binary acids consist of a single hydrogen ion and a

halogen (group 17): hydro + stem + ic acid

HCl → hydro+chlor+ic acid → hydrochloric acid

Ex.1) HF → hydro + + ic →

Ex.2) HI → hydro + + ic →

Ex.3) HBr → hydro + + ic →

6.5.1 Naming Acids

~ 26 ~

Polyatomic acids consist of some number of

hydrogen ions paired with a polyatomic ion. Only

the polyatomic's ending is modified

Replace -ate with -ic / -ite with -ous

H2CO3 → carbonate → carbonic acid

H3AsO3 → arsenite → arsenous acid

Ex.4) HNO2 → nitrite →

Ex.5) HNO3 → →

Ex.6) H2CrO4 → →

Ex.7) HC2H3O2 → →

Ex.8) H2Cr2O7 → →

Ex.9) HMnO4 → →

~ 27 ~

Phosphorus and sulfur polys keep a little more of

their poly stems when they are named as acids:

Ex.10) H3PO4 → phosphate →

Ex.11) H2SO4 → sulfate →

Ex.12) H2SO3 → sulfite →

Assorted Practice:

Ex.13) HCl →

Ex.14) HClO → →

Ex.15) HClO2 → →

Ex.16) HClO3 → →

Ex.17) HClO4 → →

*Note: HCN is known as hydrocyanic acid.

~ 28 ~

Acids are corrosive substances capable of giving

hydrogen ions (H+) in chemical reactions. Their

names are easily recognized as they will contain the

word "acid" and contain -ic or -ous in place of the

other, more common endings.

If an acid name starts with hydro- and ends in -ic, it

is a binary acid, made up of hydrogen and a single

halogen. Assemble the formula via swap and drop:

hydrochloric acid → H+ Cl- → HCl

Ex.1) hydrobromic acid → →

Ex.2) hydroiodic acid → →

Ex.3) hydrofluoric acid → →

Ex.4) hydroastatic acid → →

6.5.2 Building Acid Formulas

~ 29 ~

Polyatomic acid names will end in -ic or -ous, but

will NOT start with hydro- . Identify the polyatomic

ion involved and swap/drop it with a hydrogen ion:

( -ic comes from -ate / -ous comes from -ite)

sulfuric acid → H+ (SO4) 2-

→ H2SO4

Ex.5) dichromic acid → →

Ex.6) chlorous acid → →

Ex.7) perchloric acid → →

Ex.8) chromic acid → →

Ex.9) carbonic acid → →

Ex.10) sulfurous acid → →

Ex.11) phosphoric acid → →

~ 30 ~

Hydrates are compounds which have trapped water

molecules in definite ratios within their crystal

lattices. The water is technically not part of the

compound, but is an integral part of the crystal itself.

We show this distinction in the unique way we write

the formula for hydrates, using the hydrate dot (•).

Pattern: Ionic/Poly name, then prefix-hydrate.

CuSO4•5H2O = copper (II) sulfate pentahydrate

6.6.1 Naming Hydrates

~ 31 ~

Hydrate prefixes are the same as those used for

covalent naming, with a few additions:

1/2 Hemi- 4 Tetra - 9 Nona -

1 Mono - 5 Penta - 10 Deca -

1.5 Sesqui - 6 Hexa - 11 Undeca -

2 Di - 7 Hepta - 12 Dodeca -

3 Tri - 8 Octa -

Name the ionic or polyatomic according to the

"rules" you already know. Add a prefix equal to the

number of water molecules and the word "hydrate"

to complete the name:

BaCl2•2H2O → barium chloride dihydrate

Ex.1) CoF2•4H2O → cobalt (II) fluoride ____ hydrate

Ex.2) PbBr2•6H2O →

~ 32 ~

Ex.3) MgSO4•8H2O

Ex.4) Fe2SO4•1.5H2O →

Ex.5) NH4NO3•3H2O →

Ex.6) Zn(ClO4)2•12H2O →

Ex.7) HF•7H2O →

Ex.8) (NH4)3PO4•11H2O →

Ex.9) H2SO3•H2O →

~ 33 ~

Hydrate formulas are created in two steps. First, use

swap/drop to determine the name of the compound,

then add a "dot" and the correct number of water

molecules. Hydrate = water!

Sodium sulfide dihydrate

Na+ S2- → Na2S → Na2S•2H2O

Ex.1) calcium oxide tetrahydrate →

Ex.2) silver chloride heptahydrate →

Ex.3) zinc chlorate pentahydrate →

Ex.4) sodium chlorite dihydrate →

6.6.2 Writing Hydrate Formulas

~ 34 ~

Ex.5) iron (III) phosphate undecahydrate →

Ex.6) zinc bromide nonahydrate →

Ex.7) vanadium (VI) chlorate decahydrate →

Ex.8) sodium sulfite pentahydrate →

Ex.9) carbonic acid dihydrate →

Ex.10) aluminum hydroxide hemihydrate →

Ex.11) sulfurous acid dodecahydrate →