The reaction of sodium with an anthracite sample is studied at 700 degrees C for various sodium relative pressures and is compared to the simple ease of intercalation in a pitch coke. The behaviour of the anthracite sample is similar to that observed with non graphitizing carbon : intercalation and capillary condensation take place simultaneously. The sodium intercalation is found to be very sensitive to the previous heat treatment temperature of the sample, which determines the extent of order, and perfection of the carbon layers.