Nomenclature of Inorganic Chemistry

1. Elements & oxidation numbers

2. Types of nomenclature

3. Ions4. Binary compounds

1. Hydrides2. Oxides3. Peroxides4. Binary salts

5. Hydroxides6. Oxoacids7. Oxosalts8. Acid salts

Patricio Gómez Lesarri

1. Elements & oxidation numbers

An element is any chemical substance which consists of just one type of atom.

Chemical elements are ordered in the periodic table according to their atomic number.

Each column, which is called group, has elements of simmilar chemical properties.

1. Elements & oxidation numbers

Oxidation number: electric charge that an element has when it is combined

Valence: Ability to bind to a certain number of atoms

Atoms try to get a full valence shell, in other words, 8 electrons in the outer shell

Metals: elements which tend to lose electrons, so they become positive

Nonmetals: elements which tend to gain electrons, so they become negative

Noble gases: stable elements, which don´t combine

Valence Elements1 Group 1 (Lithium, Sodium,

Potassium, Rubidium, Caesium) & Silver

2 Group 2 (Beryllium, Magnesium, Calcium, Strontium, Barium,), Zinc & Cadmium

3 Boron & Aluminium1,2 Copper & Mercury1,3 Gold2,3 Iron, Cobalt & Nickel2,4 Palladium,, Platinum, Tin &

lead

Valence

Elements

- 1 Fluorine, Chlorine, Bromine & iodine

- 2 Sulphur, Selenium & Tellurium

1. Figuring out oxidation numbers

Oxidation number for a neutral element equals to zero

Oxidation number for a simple ion equals to its own electric charge

Oxidation number for hydrogen is +1 , except in hydrides, in which it´s – 1

Oxidation number for oxygen is – 2, except in peroxides, in which it is – 1

The sum of all the atom´s oxidation numbers in a neutral substance equals to zero

The sum of all the atom´s oxidation numbers in an ion equals to its own charge

2. Types of nomenclatureCompositional nomenclature

easiest system of nomenclature based on the composition of the substance.

Stoichiometric naming system use multiplicative prefixes, such as di, tri, tetra, SO3 : sulphur trioxide H2SO4: dihydrogen (tetraoxidosulphate

Numbers of oxidation can also be used to specify the substance FeCl3: iron (III) choride

Additive nomenclature Central atom and ligands: SO3 : trioxidosulphur

H2SO4: dihydroxidodioxidosulphur

Substitutive Parent hydrides which are modified by

substituting atoms of hydrogen by different groups of atoms

CH4: methane CH3Cl: chloromethane PH3: phosphane PCl3: trichlorophosphane

3. Ions Atom or molecule which has electrical charge

A cation is a positively charged ion. An anion is a negatively charged ion

Monovalent cations: same name: e.g.: Na+: sodium ion; Al3+: aluminium ion

Multivalent cations: labeled with a Roman numeral or just a number in parenthesis following the cation´s name

e. g. Cu*: copper (I) ion; Cu2+: copper (+ 2) ion.

Some cations have a common name: ammonium, NH4

+.

Monoatomic anions adding the sufix –ide Cl (chlorine) Cl- : chloride; O: oxygen O2- : oxide

Polyatomic anions: adding the suffixes –ite and –ate to the root of the element

4. Binary substances: formula writing

Substances which consist of two elements, on positive and the other negative

Positive element precedes negative.

Stoichiometry is the ratio of both elements in the formula, which is shown with subscripts. If both charges are the same, the

ratio is 1:1: no subscripts are needed

If oxidation numbers are different, use the “criss-cross” method.

Reduce subscripts when possible

4. Binary substances: naming systems

Name of the cation followed by the name of the anion

Metal + Nonmetal + IDE

Stoichiometric Compositional name: multiplicative prefixes are used to show the numeber of atmos of each element in the formula. These prefixes are:

mono- (1:1), di-, tri-, tetra-, penta-, hexa- & hepta- .

Oxidation numbers: oxidation numbers are shown after the name of the cation to determine the number of anion atoms

IUPAC recommends the use of stoichichiometric nomenclature

Traditional nomenclature is not accepted

4.1. Hydrides

Consist of metal & hydrogen

Oxidation number for hydrogen: -1

General formula: MHx.

Naming system: cation + hydride

Multivalent cations: stoichiometric or oxidation numbers

4.1. Parent hydrides

Substitutive nomenclature

IUPAC before 2005

NH3: ammonia

PH3: phosphine

AsH3: arsine

SbH3: estibine

H2O: water

(oxidane)

NH3: ammonia or azane

CH4: methane

BH3: borane

  PH3: phospha

ne

SiH4: silane

 

  AsH3: arsane

   

  SbH3: stibane

   

4.2. OxidesConsist of an element &

oxygen

Oxidation number for oxygen: - 2

General formula X2Ox,XOx/2 x even number

Naming: element + oxide

Multivalent cations: stoichiometric or oxidation numbers

4.3. Peroxides

Consist of peroxide ion O2 2-, which has valence - 2, and alcaline or earthalcaline

General formula M2(O2)x.

Naming:

Element + peroxide

Stoichiometric: Element + dioxide

4.4. Binary salts: halidesOxidation number

halogen: - 1

Consist of an element an halogen

General formula : MXm.

Naming element + root + ide

Multivalent cations: stoichiometric or oxidation numbers

Binary acids: hydrogen + halogen

Traditional Hydro + root + ic acid

Formula

Stoichiometric

Tradicional

HF Hydrogen fluoride

Hydrofluoric acid

HCl Hydrogen chloride

Hydrochloric acid

HBr Hydrogen bromide

Hydrobromic acid

HI Hydrogen iodide

Hydroiodic acid

4.5. Binary salts: chalcogens

Formula

Stoichiometric

Traditional

H2S Hydrogen sulphide

Hydrosulphuric acid

H2Se Hydrogen selenide

Hydroselenic acid

H2Te Hydrogen telluride

Hydrotelluric acid

Chalchogens : Sulphur , selenium, tellurium

Oxidation number chalcogens: - 2

General formula : X2Sx, XSx/2 x even number

Naming element + root + ide

Multivalent cations: stoichiometric or oxidation numbers

Binary acids: hydrogen + chalcogen

Traditional Hydro + root + ic acid

5. Hidroxides

Substances whic consist of element and hydroxide group

Valence for hydroxide: - 1

General formula M(OH)x.

Naming: element + hydroxide

Multivalent cations: stoichiometric or oxidation numbers

6. Oxoacids Substances which consist of

nonmetal, oxygen and hydrogen

General formula HaXbOc

Positive ion precedes negative one

Types of nomenclature

Hydrogen nomenclature: Compositional nomenclature Hydrogen( Prefix+oxido+element+ate)

Traditional Set of prefixes and suffixes combined to the name of the element hypo-ous, -ous, -ic y per-ic), related to the oxidation number of the central atom

6. OxoacidsPrefijos Nº

OXIDCl / Br / I N P / As / Sb B

HYPO-OUS

I HClO, HBrO …

- - -

- OUS III HClO2, HBrO2 .

HNO2 H3PO3 -ousH4P2O5 di - ous

HBO2 meta- ic

H3BO3 - ic  

- IC V HClO3, HBrO3..

HNO3 HPO3 meta- icH3PO4 -ic H4P2O7 di - ic

 -

PER-IC VII HClO4, HBrO4..

- - -Phosphorous, arsenic, antimony, boron: Three different acids

Meta

Orto : one molecule of water added

HPO3 + H2O → H3PO4

Di : dimer. Condensation of 2 molecules of acid

2 H3PO4 → H4P2O7 + H2O

6. OxoacidsPrefijos Nº S / Se / Te Cr C Si Mn HYPO-

OUSII H2SO2,

H2SeO2..- - - -

- OUS IV H2SO3,

H2SeO3..- H2CO3

- icH2SiO3 meta

H4SiO4

-

- IC VI H2SO4,

H2SeO4..H2S2O7 di -

ic

H2CrO4

H2Cr2O7 di - ic

- - H2MnO4

PER - IC VII - - - - HMnO4

Sulphur & chromium: dimers

Silicon: meta

7. Oxosalts Traditional: cation + anion

Multivalent cations:

cation (oxidation number) + anion

Stoichiometric:

Metal Prefix + oxido + element+ate)

7. OxosaltsSalts: hydrogen atoms are substituted by

metals

Acid valence: number of atoms of hydrogen lost by the acid

Anion: OUS ITE

IC ATE

8. Acid salts

Acid doesn´t lose all the atoms of hydrogen

Traditional: cation +hydrogen anion

Stoichiometric:

Metal hydrogenPrefix + oxido + element+ate)

Prefix Bi: forbidden