| Heats of Formation | |
|
These are molar heats of formation for anions and cations in aqueous solution. In all cases, the heats of formation are given in kJ/mol at 25°C for 1 mole of the ion.
| Cations | DHf (kJ/mol) | Anions | DHf (kJ/mol) |
| Ag+(aq) | +105.9 | Br-(aq) | -120.9 |
| Al3+(aq) | -524.7 | Cl-(aq) | -167.4 |
| Ba2+(aq) | -538.4 | ClO3-(aq) | -98.3 |
| Ca2+(aq) | -543.0 | ClO4-(aq) | -131.4 |
| Cd2+(aq) | -72.4 | CO32-(aq) | -676.3 |
| Cu2+(aq) | +64.4 | CrO42-(aq) | -863.2 |
| Fe2+(aq) | -87.9 | F-(aq) | -329.1 |
| Fe3+(aq) | -47.7 | HCO3-(aq) | -691.1 |
| H+(aq) | 0.0 | H2PO4-(aq) | -1302.5 |
| K+(aq) | -251.2 | HPO42-(aq) | -1298.7 |
| Li+(aq) | -278.5 | I-(aq) | -55.9 |
| Mg2+(aq) | -462.0 | MnO4-(aq) | -518.4 |
| Mn2+(aq) | -218.8 | NO3-(aq) | -206.6 |
| Na+(aq) | -239.7 | OH-(aq) | -229.9 |
| NH4+(aq) | -132.8 | PO43-(aq) | -1284.1 |
| Ni2+(aq) | -64.0 | S2-(aq) | +41.8 |
| Pb2+(aq) | +1.6 | SO42-(aq) | -907.5 |
| Sn2+(aq) | -10.0 | ||
| Zn2+(aq) | -152.4 |
Reference: Masterton, Slowinski, Stanitski, Chemical Principles, CBS College Publishing, 1983.
