A valve block leak-tightly joinable to a receptacle to form a container suitable for liquid storage/vapor dispensing, and gas purification applications. The valve block is provided with first and second valve ports with which valves may be employed to flow feed gas through the valve block and receptacle. To effect purging the valve block ports and gas flow passages, the valve block is provided with a purge valve port which may be opened while the first and second valve ports are closed, to remove dead space hold-up gas from the respective ports and flow passages of the block prior to initiation of vapor dispensing or gas purification operation. The disclosed container is particularly advantageous for dispensing or purifying source reagent compounds for elements of Group III and Group V, in semiconductor manufacturing applications.