This section lists some binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and some other compounds of cobalt. For each compound, a formal oxidation number for cobalt is given, but the usefulness of this number is limited forp-block elements in particular. Based upon that oxidation number, an electronic configuration is also given but note that for more exotic compounds you should view this as a guide only.
In compounds of cobalt (where known), the most common oxidation numbers of cobalt are:3, and 2.
Hydrides
The term hydride is used to indicate compounds of the type MxHy and not necessarily to indicate that any compounds listed behave as hydrides chemically.
- none listed
Fluorides
- Cobalt difluoride: CoF2
- Cobalt trifluoride: CoF3
- Cobalt tetrafluoride: CoF4
Chlorides
- Cobalt dichloride: CoCl2
- Cobalt trichloride: CoCl3
- Cobalt dichloride dihydrate: CoCl2.2H2O
Bromides
- Cobalt dibromide: CoBr2
Iodides
- Cobalt diiodide: CoI2
Oxides
- Cobalt oxide: CoO
- Dicobalt trioxide: Co2O3
- Tricobalt tetraoxide: Co3O4
Sulfides
- Cobalt sulphide: CoS
- Cobalt persulphide: CoS2
- Dicobalt trisulphide: Co2S3
Selenides
- Cobalt selenide: CoSe
Tellurides
- Cobalt telluride: CoTe
Nitrides
- none listed
Carbonyls
- Dicobalt octacarbonyl: Co2(CO)8
- Tetracobalt dodecacarbonyl: Co4(CO)12
- Hexacobalt hexadecacarbonyl: Co6(CO)16
Complexes
- Tricobalt diphosphate octahydrate: Co3(PO4)2.8H2O
- Cobalt nitrate hexahydrate: Co(NO3)2.6H2O
- Hexaaquocobalt dichloride: CoCl2.6H2O
- Tetraquocobalt difluoride: CoF2.4H2O
- Cobalt dibromide hexahydrate: CoBr2.6H2O
- Cobalt sulphate heptahydrate: CoSO4.7H2O