Keying in Molecular Formulae
Use true one- or two-letter atomic symbols, starting each with a capital letter. All 104 elements are recognized.
Follow the symbol with the number of such atoms. No number is taken to mean one (1).
Elements can come in any order. They will be re-ordered if needed to present C and H first, followed by other elements alphabetically.
For example,
NaOC2H5
or
C2H5ONa
can be used and will appear
C2H5NaO
.
Don't confuse O (as in Oxygen) with 0 (zero).
You may repeat any one element as often as desired.
For instance, ethanol can be written
HOCH2CH3
or
C2H6O
.
You may group elements together between brackets.
For instance, isopropanol is
C3H8O
or
(CH3)2CHOH
.
Up to 32 nested bracket levels can be used but all open brackets must be eventually closed.
For instance, Sharpless' catalyst can be written
(Ti((OCHCOOCH(CH3)2)2)2(OCH(CH3)2)2)2
Formulae can include addends, such as water in hydrates. Use the "*" (asterisk) symbol and not "." (period or dot).
A tetra-hydrated sandwich complex of 15-crown-5 and CsCl can be written
CsCl*2((CH2)2O)5*4H2O
.
Non-integral values can be used following the "*". If no number is given, "1" will be assumed.
An example of a partly solvated molecule is
C19H21N5*1.5CH3OH
.
The following group abbreviations are also recognized and treated as elements:
Me
= methyl CH
3
Et
= ethyl C
2
H
5
Pp
= propyl C
3
H
7
Bu
= butyl C
4
H
9
Ph
= phenyl C
6
H
5
Ts
= tosyl C
7
H
7
SO
2
Cp
= cyclopentadienyl C
5
H
5