Numerical Prefixes Commonly Used in Forming Chemical Names
Numeral Prefix Numeral Prefix Numeral Prefix
1/2 hemi- 13 trideca- 28 octacosa-
1 mono- 14 tetradeca- 29 nonacosa-
3/2 sesqui- 15 pentadeca- 30 triaconta-
2 di-, bi- 16 hexadeca- 40 tetraconta-
3 tri- 17 heptadeca- 50 pentaconta-
4 tetra- 18 octadeca- 60 hexaconta-
5 penta- 19 nonadeca- 70 heptaconta-
6 hexa- 20 eicosa- 80 octaconta-
7 hepta- 21 heneicosa- 90 nonaconta-
8 octa- 22 docosa- 100 hecta-
9 nona-, ennea- 23 tricosa- 101 henhecta-
10 deca- 24 tetracosa- 102 dohecta-
11 undeca-, hendeca- 25 pentacosa- 110 decahecta-
12 dodeca- 26 hexacosa- 120 eicosahecta-
27 heptacosa- 200 dicta-
SI Prefixes
Factor Prefix Symbol Factor Prefix Symbol
10 −^18 atto a^10 deca d
10 −^15 femto f 102 hecto h
10 −^12 pico p 103 kilo k
10 −^9 nano n 106 mega M
10 −^6 micro μ 109 giga G
10 −^3 milli m^1012 tera T
10 −^2 centi c 1015 peta P
10 −^1 deci d 1018 exa E