The high-pressure behaviour of 3R-NbS2
  The high pressure behaviour of 3R-NbS2 has been investigated by angle-dispersive X-ray powder diffraction using diamond anvil cells up to 14 GPa. The compression behaviour of the structure is highly anisotropic. The compressibility perpendicular to the layers is 2.5 times higher than within the layers. A fit of a 3rd-order Birch-Murnaghan equation of state gave a volume at zero pressure V0=174(1)\AA^3 and a bulk modulus b0=57(1) GPa, with a pressure derivative b'=8.6(5). 
L. Ehm, K. Knorr, W. Depmeier