The molecular structure of thiazole, determined by the combined analysis of gas-phase electron diffraction (GED) data and rotational constants and byab initio calculations

The molecular structure of thiazole has been determined by the joint analys is of data obtained from gas-phase electron diffraction (GED), microwave (M W) spectroscopy and ab initio molecular orbital calculations. The combined approach, making use of the SARACEN method, has led to a very precise struc ture in which all independent geometric parameters are well defined, and th e quoted uncertainties reflect the true accuracy of the measurements. The g round-state average (= r(alpha)degrees or r(z)) structural parameters obtai ned in the combined study of thiazole were; r[S(1)-C(2)] = 172.37(11) pm, r [S(1)-C(5)] = 171.38(13) pm, r[C(2)-N(3)] = 131.0(2) pm, r[C(4)-C(5)] pm = 136.90(19) pm, r[N(3)-C(4)] = 137.2(2) pm, r[C(2)-H(6)] = 109.8(4) pm, r[C( 4)-H(7)] = 109.9(4) pm, r[C(5)-H(8)] = 109.7(4) pm, C(2)-S(1)-C(5)= 89.41(4 )degrees, S(1)-C(2)-N(3) = 115.16(6)degrees, S(1)-C(5)-C(4) = 109.52(8)degr ees, C(2)-N(3)-C(4) = 109.97(9)degrees N(3)-C(4)-C(5) = 115.95(11)degrees, S(1)-C(2)-H(6) = 120.7(2)degrees, C(5)-C(4)-H(7) = 125.0(4)degrees, S(1)-C( 5)-H(8) = 121.7(2)degrees.