When the system being studied is an ion, the charge, n, on the ion must be supplied by CHARGE=n. For cations n can be 1, 2, 3, etc.; for anions -1 or -2 or -3, etc. Examples of various charged systems are given in the Table below.
Table:
Use of CHARGE=n|
Ion |
Keyword |
Ion |
Keyword |
|
|
|
|
|
|
NH4+ |
CHARGE=1 |
CH3COO- |
CHARGE=-1 |
|
C2H5+ |
CHARGE=1 |
(COO)= |
CHARGE=-2 |
|
SO4= |
CHARGE=-2 |
PO4-3 |
CHARGE=-3 |
|
HSO4- |
CHARGE=-1 |
H2PO4- |
CHARGE=-1 |