New ternary lithium-potassium (rubidium)-rare earth molybdates

Phase formation in the systems Li2MoO4-Me2MoO4-Ln2(MoO4)3, where M = K, Rb; Ln = La-Lu, Y) was studied. Formation of ternary molybdates is detected in the systems Li2MoO4-K2MoO4-Ln2(MoO4)3 (Ln = Nd-Lu, Y), and Li2MoO4-Rb2MoO4-Ln2(MoO4)3 (Ln = La-Eu). It is ascertained that with an increase in total radius of alkali metals the range of existence of the ternary molybdates shifts to the side of large rare earth elements. The ternary molybdates are unstable and above 610-725 deg C they decompose in solid phase into corresponding double molybdates. Unit cell parameters of the phases synthesized are presented