CHAPTER 6 Chemical Bonds

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CHAPTER 6 Chemical Bonds
Lecture
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Original Production
Time
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Section 6.3
Naming Compounds and Writing Formulas
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Have you ever hear of the saying In the
limelight?
Jet bathes in the limelight of success at the
ARIA Awards - from left, Mark Wilson, Chris
Cester, Nic Cester and Cameron Muncey. Photo
Edwina Pickles
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How about Whitewash?
"Say, Tom, let me whitewash a little." Tom
considered, was about to consent but he altered
his mind "No no I reckon it wouldn't hardly
do, Ben. You see, Aunt Polly's awful particular
about this fence right here on the street, you
know but if it was the back fence I wouldnt
mind and she wouldnt. Yes, she's awful
particular about this fence it's got to be done
very careful I reckon there ainit one boy in a
thousand, maybe two thousand, that can do it the
way it's got to be done." "No is that so? Oh
come, now lemme, just try. Only just a little
I'd let you, if you was me, Tom. ...".
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QuickLime Main Uses Purification of steel and
other metal by removing impurities Manufacturing
of Calcium Carbide Manufacturing of Calcium
Silicate Bricks Sugar refining process for
purifying raw sugar Effluent treatment for waste
water neutralisation Building and construction
works for wall plastering Soil stabilisation for
construction of road beds, parking lots and
building bases As moisture absorbing agent
Maybe quicklime?
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OK, surely pickling lime?
http//www.holcim.com/NZ/EN/id/1610645477/mod/gnm2
0/page/product.html
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The Chemistry of Lime includes two classes of
minerals the silicates and the aluminosilicates.
The carbonates form another commercially
important class of minerals. Aragonite and
calcite are two minerals formed from calcium
carbonate (CaCO3), while dolomite is a mineral
containing calcium magnesium carbonate
(CaMg(CO3)2). Rocks formed from calcite and
dolomite minerals are called limestones. They are
formed either from the accretion of carbonaceous
animal remains (seashells, coral, microfossils)
or from the precipitation of dissolved calcium
carbonate from mineral waters. Calcium carbonate
is white in color, though impurities may lend
color to rocks and minerals. The carbonates are
chalky in consistency. In fact, chalk is one
variety of limestone, though modern classrooms
use "chalk" made of gypsum (calcium sulfate).
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Lime (calcium oxide) is produced by heating
limestone or seashells (calcium carbonate). The
chemistry of calcium carbonate is similar to that
of sodium carbonate and potassium carbonate
except that calcium carbonate is not soluble in
water. Consequently, calcium carbonate does not
produce an alkaline solution in water as sodium
and potassium carbonate do. When calcium
carbonate is heated, carbon dioxide is driven off
leaving calcium oxide behind. CaCO3(s) -----gt
CaO(s) CO2(g)
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Because of the many common names given to this
lime compound (calcium oxide, CaO), chemists came
up with a naming system based on a compounds
composition. Name calcium oxide Formula CaO
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• Describing Ionic Compounds the name of an ionic
  compound must distinguish the compound from other
  ionic compounds containing the same elements.
  The formula of an ionic compound describes the
  ratio of the ions in the compound.

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• Binary Ionic Compounds
• - a compound made from only two elements is
  called a binary compound
• - to name an IONIC binary compound, start with
  the cation and follow this with the anion
• - finish the name by substituting the suffix
  -ide

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2. Metals With Multiple Ions (charges) (a.k.a.,
transition metals) - metals in group 1A
(alkali metals) and 2A (alkaline earth metals)
have fixed charges and 2
respectively - aluminum has a fixed charge of
3 - many of the transition metals, on the
other hand, have variable charges
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3. Polyatomic Ions a covalently bonded GROUP of
atoms that has a positive or negative charge and
acts as a SINGLE UNIT - electron dot uses
brackets - most polyatomic ions are anions
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• Writing Formulas for Ionic Compounds
• - comes from the NAME of the compound
• - cation symbol comes first followed by the
  anion symbol
• - subscripts are used to show the ratio of ions
  in the compound
• - the total charges on the cations and anions
  must add up to zero (0)

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Practice Problems a) barium chloride b)
lithium sulfide c) aluminum oxide

• BrCl2
• Li2S
• Al2O3

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IONIC COMPOUNDS
Compounds are two or more elements that are held
together by opposite charge attraction.
8 ()10 (-)-2 Charge
Oxygen-8
Magnesium-12
12 ()10 (-)2 Charge
Metal
Non-metal
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Metals combine with non-metals Metals loose
electrons to non-metals They then attract because
their charges will be opposite.
Metals
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Negative Ions (single atoms)
-3
-2
-1

• Most of the negative ions have a set negative
  charge

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-1
1
-2
-3
3
2
1
2
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• For example the oxy-salts of chlorine, bromine
  and iodine have many trends in common. Look for
  them below

The next table contains the polyatomic ions that
need to be committed to memory. Remember to
learn the name, formula and oxidation number
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POLYATOMIC IONS (charged building
blocks)Polyatomic ions are mostly made of two
non-metals.
Ions with -1 charge perbromate BrO4-1 bromate
BrO3-1 bromite BrO2-1 hypobromite
BrO-1 perchlorate ClO4-1 chlorate
ClO3-1 chlorite ClO2-1 hypochlorite
ClO-1 periodate IO4-1 iodate
IO3-1 iodite IO2-1 hypoiodite
IO-1
nitrate NO3-1 nitrite NO2-1 hydroxide OH-1 cyanid
e CN-1 acetate C2H3O2-1 Permanganate MnO4-1 bicar
bonate HCO3-1 Ions with a -2 Charge carbonate CO3
-2 sulfate SO4-2
sulfite SO3-2 chromate
CrO4-2 dichromate Cr2O7-2 oxalate
C2O4-2 Ions with a -3 Charge phosphate
PO4-3 phosphite PO3-3 arsenate
AsO4-3 Ions with 1 charge ammonium ion NH41
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These polyatomic ions match the charge of the
single element
-1
Ions with -1 charge perbromate BrO4-1 bromate
BrO3-1 bromite BrO2-1 hypobromite
BrO-1 perchlorate ClO4-1 chlorate
ClO3-1 chlorite ClO2-1 hypochlorite
ClO-1 periodate IO4-1 iodate
IO3-1 iodite IO2-1 hypoiodite
IO-1
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These polyatomic ions match the charge of the
single element
Ions with a -2 Charge sulfate SO4-2 sulfite
SO3-2 Ions with a -3 Charge phosphate
PO4-3 phosphite PO3-3
-3
-2
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• It is also important to memorize the oxidation
  of the ions that have fixed oxidation numbers
  (positive or negative). In particular, those
  from groups 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A and
  the elements Zn, Cd and Ag. Use the following
  periodic chart to determine their oxidation
  numbers. Just click on the element symbol

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Elements with Fixed Oxidation Numbers
1
2
3
0
-4
-3
-2
-1
8A
7A
1A
H
H
He
6A
5A
4A
3A
2A
N
B
C
O
F
Ne
Li
Be
Click on element to see its oxidation number(s)
Al
Si
P
S
Cl
Ar
Na
Mg
Sc
Ti
V
Cr
Mn
Fe
K
Ca
Ga
Ge
As
Se
Br
Kr
Co
Ni
Cu
Zn
Y
Zr
Nb
Mo
Tc
Ru
Rb
Sr
In
Sn
Sb
Te
I
Xe
Rh
Pd
Ag
Cd
La
Hf
Ta
Re
Os
Ce
Ba
Tl
Pb
Bi
Po
At
Rn
Ir
Pt
Au
Hg
W
Ac
Rf
Db
Sg
Rh
Hs
Fr
Ra
Mt
Next Slide
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Naming Ionic Compounds

• The positive ion (usually a metal) is named first
  while the negative ion (a non-metal or a
  polyatomic ion) is named last.
• The charge on the negative ion is used to
  determine the charge on the positive ion.
• In-order for the total oxidation state to be
  zero, the total positive charge must equal the
  total negative charge. A simple algebraic
  equation can be used to determine the charge on a
  single metal ion.
• This charge is expressed as a Roman Numeral in
  parenthesis that immediately follows the name of
  the metal.

CuSO4 Cu?SO4-2 x (-2)0 X 2
Copper (II) Sulfate
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Naming Ionic Compounds

• The positive ion (usually a metal) is named first
  while the negative ion (a non-metal or a
  polyatomic ion) is named last.
• The charge on the negative ion is used to
  determine the charge on the positive ion.
• In-order for the total oxidation state to be
  zero, the total positive charge must equal the
  total negative charge. A simple algebraic
  equation can be used to determine the charge on a
  single metal ion.
• This charge is expressed as a Roman Numeral in
  parenthesis that immediately follows the name of
  the metal.

Cu2SO4 Cu2xSO4-2 2x (-2)0 x 1
Copper (I) Sulfate
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Naming Ionic Compounds

• If the positive ion is one that has a fixed
  oxidation number then no Roman Numeral is used.
• Everyone should know the charge of fixed ions.
  These include metals in group 1A, 2A and the
  specific metals Al, Zn, Cd Ag (zinc, cadmium
  and silver).

CaSO4
Calcium Sulfate
No Roman Numeral
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• If the ionic compound is binary it will end in
  -ide. However, not all compounds that end in
  -ide are binary. For example sodium hydroxide
  has the formulaNaOH (three different kinds of
  atoms).
• If the negative ion is a polyatomic ion the
  compound is no longer binary. The ending will be
  that carried by the polyatomic ion. These
  endings are either -ate or -ite.
• Hydrated compounds are named using a combination
  of both the stock system and prefixes. A prefix
  is used to denote the number of water molecules
  attached to the ionic formula. hydrate is used
  as the name indicating that water is attached.
  For example, copper(II) sulfate pentahydrate has
  the formula CuSO4.5H2O

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Examples 1- Formulas to Names

• CuSO3

1. Write the names of the ions
0
-2
2. Determine the charge of the positive ion
Cu
SO3
2
x
X (- 2) 0
Im a polyatomic ion
You must know the charge on the sulfite ion is -2
The sum of the positive and negative charges must
equal zero
2 2
X 2
copper
sulfite
(II)
Final Name
Next
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Examples 2- Formulas to Names
1. Write the names of the ions
Im a polyatomic ion

• KMnO4

potassium
permanganate
Final Name
If the positive ion has a fixed charge, you are
finished.
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Examples 3- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
Im a polyatomic ion

• NH4NO3

ammonium
nitrate
Final Name
If the positive ion has a fixed charge, you are
finished.
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Examples 4- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
X 2
X 2(-1) 0
Snx (F-1)2 0

• SnF2

tin
fluoride
(II)
Final Name
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Examples 5- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
Im a polyatomic ion

• Ba(ClO4)2

barium
perchlorate
Final Name
If the positive ion has a fixed charge, you are
finished.
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Examples 6- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
X 1
2X (-2) 0
2Cux (S)-2 0
Im not a polyatomic ion

• Cu2S

copper
sulfide
(I)
Final Name
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Examples 6- Formulas to Names

• Cu2S

1. Write the names of the ions
-2
2. Determine the charge of the positive ion
(Cu )2
S
1
x
2X (- 2) 0
The sum of the positive and negative charges must
equal zero
You must know the charge on the sulfide ion is -2
2 2
2X 2
X 1
copper
sulfide
(I)
Final Name
Next
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Examples 7- Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
X 1
2X (-2) 0
2(Nax)(Cr2O7)-2 0
Im a polyatomic ion

• Na2Cr2O7

sodium
dichromate
(I)
If the positive ion has a fixed charge, it is not
shown
Final Name
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Examples 8 - Formulas to Names
1. Write the names of the ions
2. Determine the charge of the positive ion
Im a polyatomic ion

• LiCN

lithium
cyanide
If the positive ion has a fixed charge, you are
finished.
Final Name
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Writing Ionic Formulas

• It is easier to write the formula of an ionic
  compound from its name than the reverse.
• The oxidation number of the negative ion must be
  memorized in all cases. Refer to the table of
  polyatomic ions.

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Example 1-Names to Formulas
1. Write symbols of elements
2. Determine number of ions
(Al )x(Cl-1)y 0
3
What is the Lowest Common Multiple LCM of 3 and
1. Do not worry about the sign(/-)

• aluminum chloride

If there is no Roman Numeral, you need to know
the fixed oxidation number of the positive ion.

Cl
Al
3
1
Final Formula
If there is only one atom the 1 is not shown
Next
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Example 1-Names to Formulas

• aluminum chloride

1. Write symbols of elements
2. Determine number of ions
(Al )x(Cl-1)y
3
If there is no Roman Numeral, you must know the
oxidation number of the positive ion.
If there is no Roman Numeral, you must know the
oxidation number of the positive ion.
For aluminum, a 1 is multiplied times the 3 to
give a 3 charge
What is the Lowest Common Multiple LCM of 3 and
1. Do not worry about the sign(/-)
What is the Lowest Common Multiple LCM of 3 and
1. Do not worry about the sign(/-)
x(3) y(-1) 0
Remember all compounds are neutral, thus the
total positive charge must equal the total
negative charge
This formula says that the 3 charge of one
Al atom will cancel the-3 charge from 3 Cl atoms
For chloride, a 3 is multiplied times the -1 to
give a -3 charge
1(3) 3(-1) 0
Cl
Al
3
1
If there is only one atom the 1 is not shown
Final Formula
Next
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Example 2-Names to Formulas
1. Write symbols of elements
2X 1y
X(2) y(-1) 0
2. Determine number of ions
(Co2)x(BrO3-1)y 0

• cobalt(II) bromate

Choose the lowest set of integers thatsatisfies
the equation
BrO3
(BrO3)2
Co
1
If there is only one atom the 1 is not shown
Final Formula
Next
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Example 3-Names to Formulas
1. Write symbols of elements
3X 1y
X(3) y(-1) 0
2. Determine number of ions
(Ni3)x(C2H3O2-1)y 0

• nickel(III) acetate

Choose the lowest set of integers thatsatisfies
the equation
(C2H3O2)3
C2H3O2
Ni
1
Final Formula
If there is only one atom the 1 is not shown
Next
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Example 4-Names to Formulas
1. Write symbols of elements
1X 3y
X(1) y(-3) 0
2. Determine number of ions
(Li )x(PO4-3)y 0
1

• lithium phosphate

Choose the lowest set of integers thatsatisfies
the equation
If there is no Roman Numeral, you need to know
the fixed oxidation number of the positive ion.

If there is no Roman Numeral, you need to know
the fixed oxidation number of the positive ion.

PO4
(PO4)1
Li
3
Final Formula
If there is only one atom the 1 is not shown
Next
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Practice Problems

• By now you should have an idea of what is
  expected when naming covalent binary compounds
  using prefixes.
• In order to master this naming system you need
  to practice until you feel proficient in naming
  compounds using prefixes.

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Practice Problem 1

• Fe(NO3)3

Choose the correct name for the compound
1. Iron trinitrate
No, you do not use prefixes
2. iron(I) nitrate
No, you have the wrong oxidation number
3. iron(III) nitrite
No, you need to review polyatomic ions
4. iron(III) nitrate
Very good, click arrow to continue
5. none of the above
No, there is a correct answer
next problem
Polyatomic Ions
Periodic Chart
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Practice Problem 2

• sodium chlorite

Choose the correct formula for the compound
1. NaCl
No, you need to review prefixes
2. NaClO
No, you need to review prefixes
3. NaClO2
Very good, click arrow to continue
No, you have several errors
4. Na(ClO)2
No, there is a correct answer
5. none of the above
next problem
Prefixes
Periodic Chart
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POLYATOMIC IONS
Ions with -1 charge perbromate BrO4-1 bromate
BrO3-1 bromite BrO2-1 hypobromite
BrO-1 perchlorate ClO4-1 chlorate
ClO3-1 chlorite ClO2-1 hypochlorite
ClO-1 periodate IO4-1 iodate
IO3-1 iodite IO2-1 hypoiodite
IO-1
nitrate NO3-1 nitrite
NO2-1 hydroxide OH-1 cyanide
CN-1 thiocyanate SCN-1 acetate
C2H3O2-1 Permanganate MnO4-1 bicarbonate
HCO3-1 Ions with a -2 Charge carbonate
CO3-2 phthalate C8H4O4-2 sulfate
SO4-2
sulfite SO3-2 chromate
CrO4-2 dichromate Cr2O7-2 oxalate
C2O4-2 peroxide O2-2 Ions with a -3
Charge phosphate PO4-3 phosphite
PO3-3 arsenate AsO4-3 Ions with 1
charge ammonium ion NH41
return
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Oxidation Numbers (most common)
1
2
3
0
-4
-3
-2
-1
1A
8A
7A
H
H
He
6A
5A
4A
3A
2A
N
B
C
O
F
Ne
Li
Be
Click on element to see its oxidation number(s)
Al
Si
P
S
Cl
Ar
Na
Mg
Sc
Ti
V
Cr
Mn
Fe
K
Ca
Ga
Ge
As
Se
Br
Kr
Co
Ni
Cu
Zn
Y
Zr
Nb
Mo
Tc
Ru
Rb
Sr
In
Sn
Sb
Te
I
Xe
Rh
Pd
Ag
Cd
La
Hf
Ta
Re
Os
Ce
Ba
Tl
Pb
Bi
Po
At
Rn
Ir
Pt
Au
Hg
W
Ac
Rf
Db
Sg
Rh
Hs
Fr
Ra
Mt
Nd
Pm
Sm
Eu
Gd
Tb
Ce
Pr
Yb
Lu
Dy
Ho
Er
Tm
return
Np
Am
Cm
Bk
Th
Pa
No
Lr
Cf
Es
Fm
Md
U
Pu
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• Describing Molecular Compounds the name and
  formula of a molecular compound describe the type
  and number of atoms in a molecule of the compound
• 1. Naming Molecular Compounds
• - most metallic element appears first in the
  name (further left on periodic table)
• - if elements are in the same group, the more
  metallic element is closer to the bottom of the
  periodic table
• - add the suffix -ide to the end of the second
  element

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- Greek prefixes are used for both elements
in the molecular compound
Common Greek prefixes used in chemical names
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• Writing Molecular Formulas
• - write the symbol for the elements in the
  order the elements appear in the name
• - the prefixes indicate the number of atoms of
  each element in the molecule
• - if there is no prefix for an element in the
  name, there is only one atom of that element in
  the molecule

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dinitrogen tetraoxide carbon disulfide oxygen
difluoride phosphorus trichloride
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Naming Molecular Compounds

• Formed between two nonmetals
• Elements on the left are listed before elements
  on the right

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Naming Molecular Compounds

• Prefix name of 1st element
• Prefix base name of 2nd element -ide
• Prefixes mono (1) penta (5)
• di (2) hexa (6)
• tri (3) hepta (7)
• tetra (4) octa (8)

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Naming Molecular Compounds

• Prefixes mono (1) penta (5)
• di (2) hexa (6)
• tri (3) hepta (7)
• tetra (4) octa (8)
• CO2 ? carbon dioxide
• N2O ? dinitrogen monoxide
• You try it!
• CCl4
• N2O4
• PI3
• SO3

• carbon tetrachloride
• dinitrogen tetraoxide
• phosphorus triodide
• sulfur trioxide