The J = 1-0 transitions of the microwave spectra of (HSiCl)-Si-28-Cl-35, (HSiCl)-Si-29-Cl-37, (HSiCl)-Si-29-Cl-35, and (HSiCl)-Si-30-Cl-35 were measured at 14-15 GHz. The effective rotational constants are obtained, and the chlorine nuclear quadrupole coupling constants land nuclear spin-rotation constants of the four isotopomers are determined for the first time. These constants are compared with their values obtained from ab initio calculations.