The formation of cavitation bubbles in extended n-pentane is experimentally investigated in the temperature range of 25-100 degrees C and at pressures from -2.5 to -18.0 MPa. The liquid was extended when a pressure wave was reflected from the liquid-vapor interface. It is demonstrated that, al room temperature, primary bubbles are formed in extended n-pentane on available boiling centers. An increase in the negative pressure up to values comparable to the calculation results according to the homogeneous nucleation theory causes the coalescence of individual bubbles into continuous cavities. As the temperature rises, the extensions, giving rise to the formation of individual bubbles on available boiling centers, and the extensions, corresponding to the appearance of cavities, come closer together and, at a temperature of about 100 degrees C, almost coincide.