Knowledge Bank

The microwave spectra of $\mathrm{<mrow\; data-mjx-texclass="ORD">121</mrow>}SbC5H5$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">123</mrow>}SbC5H5$ have been assigned. Their respective ground state rotational constants are: A = 4512.69 $\pm$ 0.21 MHz, B = 1738.00 $\pm$ 0.01 MHz, C = 1254.51 $\pm$ 0.01 MHz and A = 4512.84 $\pm$ 0.15 MHz, B = 1729.80 $\pm$ 0.01 MHz, C = 1250.22 $\pm$ 0.01 MHz. The molecule is planar with $C2v$ symmetry. The Sb-C bond length is $2.04\pm 0.01\backslash AA$ the $C-Sb-C$ angle is $92.7\pm 0.5\circ$. The nuclear quadrupole coupling constants for $\mathrm{<mrow\; data-mjx-texclass="ORD">121</mrow>}Sb$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">123</mrow>}Sb$ have been determined using a first order treatment. We find: $\mathrm{<mrow\; data-mjx-texclass="ORD">121</mrow>}Xaa=456.4\pm 4.1$ MHz, $\mathrm{<mrow\; data-mjx-texclass="ORD">121</mrow>}\eta =0.396\pm 0.008$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">123</mrow>}Xbb=583.0\pm 5.3MHz,123\eta =0.399\pm 0.008$.