Carbon dichalcogenides are chemical compounds of carbon and chalcogen elements. They have the general chemical formula CZ2, where Z = O, S, Se, Te.[1][2]
This includes:
Double bonds between carbon and chalcogen elements, C=Z, become weaker the heavier the chalcogen, Z. This trend means carbon dichalcogenide monomers are less stable and more susceptible to polymerisation as Z changes from O to Te. For example, CO2 is stable, CS2 polymerises under extreme conditions, CSe2 tends to polymerise, CSeTe is unstable and CTe2 does not exist.[1] This trend is an example of the double bond rule.
In carbon dichalcogenides, C=O bond lengths are around 1.16 Å, C=S around 1.56 Å, C=Se around 1.70 Å and C=Te around 1.90 Å.[3]
Species | Formula | Z | Z′ | Bond | Bond in molecule | Bond length / Å | Method of determination | Reference |
---|---|---|---|---|---|---|---|---|
Carbon dioxide | CO2 | O | O | C=O | O=C=O | 1.163 | infrared spectroscopy | [1][3][4] |
Carbonyl sulfide | OCS | O | S | C=O | S=C=O | 1.158 | microwave spectroscopy | [5] |
Carbonyl selenide | OCSe | O | Se | C=O | Se=C=O | 1.159 | microwave spectroscopy | [3] |
Carbonyl sulfide | OCS | O | S | C=S | O=C=S | 1.560 | microwave spectroscopy | [5] |
Carbon disulfide | CS2 | S | S | C=S | S=C=S | 1.553 | infrared spectroscopy | [5] |
Thiocarbonyl selenide | SCSe | S | Se | C=S | Se=C=S | 1.553 | microwave spectroscopy | [5] |
Thiocarbonyl telluride | SCTe | S | Te | C=S | Te=C=S | 1.557 | microwave spectroscopy | [3][5][6] |
Carbonyl selenide | OCSe | O | Se | C=Se | O=C=Se | 1.709 | microwave spectroscopy | [5] |
Thiocarbonyl selenide | SCSe | S | Se | C=Se | S=C=Se | 1.693 | microwave spectroscopy | [5] |
Carbon diselenide | CSe2 | Se | Se | C=Se | Se=C=Se | 1.689 | neutron diffraction | [7] |
Thiocarbonyl telluride | SCTe | S | Te | C=Te | S=C=Te | 1.904 | microwave spectroscopy | [3][5][6] |