Following our recent study on Hg-Ba-Cu-O subsystem [1], in this paper we ha
ve enlarged our focus to a quinary Hg-Ba-Ca-Cu-O system containing all memb
ers of the HgBa2Can-1CunO2n+2 family of superconducting cuprates, whose sta
bility regions in selected sections of the P-Hg-P-O2-T phase diagram are ex
amined for fixed ratios of stable components (Ba:Ca:Cu = 2:1:2 and 2:2:3).