Crystal chemistry of howardevansite family of (Me2+)3(Me3+)(XO4)6 compounds (where Me = first row transition metal, Mg; X = P, V, As, Mo or In) is rich though their physical properties are poorly documented. Introduction of transition metals into parent compound Fe7(PO4)6 structure results in preferable occupation of the octahedral M1 and pyramidal M3 positions by Me2+ ions so that total formula transforms into (Mn2+)2Fe2+(Fe3+)4(PO4)6, (Co2+)3(Fe3+)4(PO4)6, (Ni2+)3(Fe3+)4(PO4)6 and (Cu2+)3(Fe3+)4(PO4)6. Available information about their magnetic properties is limited to antiferromagnetic order formation at TN = 47 K in nickel – doped compound. Trivalent positions can be occupied by titanium (Me = Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn), vanadium (Me = Mg, Cr, Mn, Fe, Co, Ni, Zn), chromium or indium (Me = Mg, Co, Ni, Zn). The magnesium doped compounds are mostly paramagnets. Compounds containing the combinations of transition metals with vanadium experience antiferromagnetic ordering at low temperatures of about 12 – 15 K. In present talk we present thermodynamic properties of parent compound Fe7(PO4)6 .