MICROWAVE-SPECTRUM, SUBSTITUTION STRUCTURE, AND DIPOLE-MOMENT OF THIOKETEN, H2C=C=S

The microwave spectrum of the unstable thiocarbonyl thioketen, H2CCS, has been investigated in the region 26.5-40 GHz. All singly substituted species as well as D2CCS have been studied and the derived rotational constants yield the following structural parameters: rs(CS) = 1.554 ± 0.003 A ̊, rs(CC) = 1.314 ± 0.003 A ̊, rs(CH) = 1.090 ± 0.006 A ̊, ∠s(HCH) = 120.3 ± 0.5°. The dipole moment is μ = 1.02 ± 0.01 D. Four low frequency vibrational modes have been observed and their assignments are discussed. © 1979.