The radius of gyration (S-2)(1/2), hydrodynamic radius R-H, intrinsic viscosity [eta], and second virial coefficient A(2) for cellulose tris(phenyl carbamate) (CTC) in tetrahydrofuran (THF) at 25 degrees C were determined in a wide range of molecular weights, 1.91 x 10(4) to 392 x 10(4), by static and dynamic light scattering and viscometry. Furthermore, the osmotic compressibility partial derivative c/partial derivative Pi for isotropic THF solutions of CTC samples was measured at 25 degrees C by static light scattering over wide ranges of the polymer concentration. Data of (S-2)(1/2), R-H, and [eta] were analyzed by the established quasi-two parameter theory for the wormlike chain model to determine the molar mass M-L per unit contour length and the persistence length q. On the other hand, results of A(2) and partial derivative c/partial derivative Pi were analyzed on the basis of the scaled particle theory for wormlike spherocylinders combined with the quasi-two parameter theory for A(2) to estimate the hard-core diameter d(0) and strength delta of the soft dispersion force of the CTC chain in THF. The value of M-L [=1040 (+/-70) nm(-1)] estimated is consistent with the (3/2) helical conformation of CTC in the crystal of the CTC- methyl ethyl ketone complex, while the hard-core diameter d(0) [=1.4 (+/-0.1) nm] is slightly smaller than the interchain spacing (=1.66 nm) of CTC in the same crystal. The value of q [=10.(5) (+/-1) nm] for CTC is comparable to literature values of q for some other cellulose derivatives reported so far.