1. Are formed with the acid oxides (anhydrides) + water
OXOACIDS
Are formed with the acid oxides (anhydrides) + water
a) Oxoacids from halogens, chalcogens and nitrogen: are formed by 1 molecule of anhydride and 1 molecule of water

2. OXOACIDS P, As, Sb, Bi, B, V ( valencias 3, 5)
b1) formed by one molecule of anhydride and 3 molecules of water
P2O3 + 3 H2O H3PO3 : orthophosphorous acid
P2O5 + 3H2O H3PO4: orthophosphoric acid
b2) formed by 2 molecules of ORTO minus 1 molecule of water or oxide + 2 H2O
2 H3PO H2O H4P2O5 : pyrophosphorous acid
2 H3PO4 - H2O H4P2O7 : pyrophosphoric acid
b3) formed by one molecule of ORTO minus 1 molecule of water
H3PO H2O HPO2 : metaphosphorous acid
H3PO4 - H2O HPO3 : metaphosphoric acid
THE ORTHO PREFIX CAN BE OMITTED.

3. OXOACIDS d) Mn, Tc y Re acids (with valences 4, 6,7)
e) Cr , Mo y W acids (valence 6)

4. PEROXOACIDS
The prefix peroxo-, when used in conjunction with the trivial names of acids, indicates substitution of —0— by —0—0—.
Examples:
HNO4 peroxonitric acid

5. THIOACIDS
Acids derived from oxoacids by replacement of oxygen by sulfur.
H2S202 thiosulfurous acid
H2S203 thiosulfuric acid
If more than one oxygen atom can be replaced by sulfur, the number of sulfur atoms should generally be indicated:
H3PO3S monothiophosphoric acid
H3PO2S2 dithiophosphoric acid
H2CS3 trithiocarbonic acid
H3AsS4 tetrathioarsenic acid