RULES IN NAMING

INORGANIC COMPOUND

Prepared by: STEFFHANIE D. TABLIGA

BINARY MOLECULAR COMPOUNDS

O When a pair of elements form more than one type of covalent compound, Greek prefixes are used to indicate how many of each element are in a compound.

O The more electronegative element is written last and its ending is changed to –ide.

EXAMPLES: N2O = Dinitrogen monoxide NO = Nitrogen monoxide N2O3 = Dinitrogen trioxide N205 = Dinitrogen pentoxide

SOME OF THE GREEK PREFIXES ARE GIVEN BELOW:

Mono = 1

Di = 2 Tri = 3

Tetra = 4

Penta = 5

Hexa = 6

Hepta = 7

Octa = 8

IONIC COMPOUNDS O Metals give up electrons to form

positively charged cations.O Non-metals gain electrons to form

negatively charged anions.O Ionic compounds are formed from

the Coulombic interaction between cations and anions.

WHEN WE NAME AN IONIC COMPOUND, WE WRITE: The name of the cation comes first

followed by the name of the anion, changing the name of the anion to end in –ide for monotomic anions are not altered.

EXAMPLES:• NaCl = Sodium chloride• Znl2 = Zinc iodide• NaNO3 = Sodium nitrate

In those cases where the metal can form cations of differing charges the positive charge is given by a roman numeral in parentheses.

EXAMPLES:• CuO = Copper (II) Oxide• Cu2O = Copper (I) Oxide• Cr2O3 = Chromium (III) Oxide

OXYANIONS

OOxyanions are those polyatomic anions containing oxygen. There are a large number of oxyanions, which makes it difficult to remember of their names. Fortunately there is a set of rules that makes this task much easier.

EXAMPLES:

O ClO4 = Percholorate ionO ClO3 = Chlorate ionO ClO2 = Chlorate ion O ClO = Hypochlorate ion

ACIDS A simplistic definition of an

acid is a ccompound that dissolves in water to release H+ ions.

The ending –ate is used for the most common oxyanion of a given element.

NO3 = Nitrate ion

SO42 = Sulfate ion CO32 = Carbonate ion PO43 = Phosphate ion ClO3 = Chlorate ion

The ending –ite is used for the oxyanion with the same charge, but one less oxygen than the –ate oxyanion.

NO2 = Nitrite ion SO32 = Sulfite ion PO33 = Phosphite ion ClO2 = Chlorite ion

The prefix per- is used if there is an oxyanion with the same charge but one more oxygen than the –ate oxyanion, while the prefix hypo- is used.

A simplistic definition of an acid is a compound that dissolves in water to release H+ ions to an oxyanion to balance its charge. The rules for naming simple acids are based on the names of the anions, they are given below.

o When the anion ends in –ide, change the ending to –ic and add the prefix hydro- to derive the name of the acid.

o Anion = chloride (Cl-) hydrochloric acid (HCl)

o Anion = bromide (Br-) hydrobromic acid (HBr)

o Anion = sulfide (s2) hydrosulfuric acid (H2S)

o When the anion ends in –are, change the ending to –ic to derive the name of the acid.

o Anion = chlorate (CLO3) chloric acid (HCLO3)

o Anion = sulfate (SO42) sulfuric acid (H2SO4)

o Anion = nitrate (NO3) nitric acid (HNO3)

o When the anion ends in –ite, change the ending to –ous to derive the name of the acid.

• Anion = phosphate (PO33) Phosphorus acid (H3PO3)

• Anion = chlorite (Cl02) Chlorous acid (HClO2)

• Anion = hypochlorite (ClO) Hypochlorous acid (HClO)

THANK YOU AND

GOD BLESS