Infrared laser absorption spectroscopy in conjunction with a cold molecular beam of W(CO)(6) has yielded the rotationally resolved spectrum of this spherical top molecule near 2000 cm(-1). Octahedral splitting has been resolved for the first time and is analyzed using the highly spherical top data system (hTDS) developed at Dijon. In addition, a perpendicular band of the symmetric top molecule W(C-12 O-16)(5)(CO)-C-13-O-16 was observed in natural abundance. The spectroscopic parameters derived for this molecule, together with electron-diffraction data, provided a value for B-0 of the dominant isotopomer, and a check on the consistency of the analysis of the spectra. (C) 2000 American Institute of Physics. [S0021-9606(00)00204-X].