English
Русский Phase formation in triple salt systems Rb2MoO4–AMoO4–R(MoO4)2 (A = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) and some properties of triple molybdates Rb5A0.5R1.5(MoO4)6
Abstract
As a result of studying the possibility of phase formation in triple salt systems Rb2MoO4–AMoO4–R(MoO4)2 (A – divalent elements; R = Zr, Hf) phases of the composition Rb5A0.5R1.5(MoO4)6, were obtained, which are assigned to a large family of ternary molybdates with the general formula M5A0.5R1.5(MoO4)6 (M – single valent element, A – divalent element, R = Zr, Hf) and represent a series of isostructural substances crystallizing in trigonal syngony (sp.gr. R3c или R3) [1, 2]. Crystallographic and thermal characteristics of the synthesized compounds were determined.
Methods. The subsolidus structure of the ternary salt systems Rb2MoО4–АMoO4–R(MoO4)2 was established using the “intersecting cuts” method. polycrystalline samples The powder samples compounds Rb5А0.5R1.5(MoO4)6 (A = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) were obtained by solid-phase synthesis at 500–530°C.
Results. The subsolidus structure of the ternary salt systems Rb2MoO4–AMoO4–Zr(MoO4)2 (A = Mn, Pb,), Rb2MoO4–AMoO4–R(MoO4)2 (A = Zn, Cd, R = Zr, Hf) was established. The Rb5A0.5R1.5(MoO4)6 (А = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) were obtained in powder form, their crystallographic and thermal characteristics were determined. IR and Raman spectra were recorded and analyzed for the compounds Rb5A0.5Zr1.5(MoO4)6 (A = Ni, Со, Mg, Zn), Rb5Ba0.5Zr1.5(MoO4)6.
Conclusions. Phase formation in ternary salt systems Rb2MoO4–AMoO4–R(MoO4)2 (A = Mg, Mn, Zn, Ni, Co, Cd, Ca, Pb, Sr, Ba; R = Zr, Hf) was studied and a subsolidus structure was established for six of them. Compounds Rb5A0.5R1.5(MoO4)6 were obtained by solid-phase synthesis at 500–530°C and belong to a large family of ternary molybdates with the general formula M5A0.5R1.5(MoO4)6 (M – single valent element, A – divalent element, R = Zr, Hf) and crystallize in two structural types: molybdates with large divalent metals (A = Ca, Sr, Ba, Pb) – in the structural type Tl5Pb0.5Hf1.5(MoO4)6 (пр.гр. R3, [2]), molybdates with divalent metals whose radius is less than 1Ǻ (A = Mg, Mn, Zn, Ni, Co, Cd) – in the structural type K5Mg0.5Zr1.5(MoO4)6 (пр.гр. R3c, [1]).
Methods. The subsolidus structure of the ternary salt systems Rb2MoО4–АMoO4–R(MoO4)2 was established using the “intersecting cuts” method. polycrystalline samples The powder samples compounds Rb5А0.5R1.5(MoO4)6 (A = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) were obtained by solid-phase synthesis at 500–530°C.
Results. The subsolidus structure of the ternary salt systems Rb2MoO4–AMoO4–Zr(MoO4)2 (A = Mn, Pb,), Rb2MoO4–AMoO4–R(MoO4)2 (A = Zn, Cd, R = Zr, Hf) was established. The Rb5A0.5R1.5(MoO4)6 (А = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) were obtained in powder form, their crystallographic and thermal characteristics were determined. IR and Raman spectra were recorded and analyzed for the compounds Rb5A0.5Zr1.5(MoO4)6 (A = Ni, Со, Mg, Zn), Rb5Ba0.5Zr1.5(MoO4)6.
Conclusions. Phase formation in ternary salt systems Rb2MoO4–AMoO4–R(MoO4)2 (A = Mg, Mn, Zn, Ni, Co, Cd, Ca, Pb, Sr, Ba; R = Zr, Hf) was studied and a subsolidus structure was established for six of them. Compounds Rb5A0.5R1.5(MoO4)6 were obtained by solid-phase synthesis at 500–530°C and belong to a large family of ternary molybdates with the general formula M5A0.5R1.5(MoO4)6 (M – single valent element, A – divalent element, R = Zr, Hf) and crystallize in two structural types: molybdates with large divalent metals (A = Ca, Sr, Ba, Pb) – in the structural type Tl5Pb0.5Hf1.5(MoO4)6 (пр.гр. R3, [2]), molybdates with divalent metals whose radius is less than 1Ǻ (A = Mg, Mn, Zn, Ni, Co, Cd) – in the structural type K5Mg0.5Zr1.5(MoO4)6 (пр.гр. R3c, [1]).