P. V. Klevtsov

Binary molybdates K4M2+(MoO4)3 (M2+=Mg, Mn, Co) and crystal structure of K4Mn(MoO4)3

AbstractBinary molybdates K4M2+ (MoO4)3 (M2+=Mg, Mn, Co) isostructural to triclinic \ga-K4Zn(WO4)3 were synthesized, and optimal conditions for their spontaneous crystallization were found. It was established by XRPA and DTA that at 530°C the structure of the compound with cobalt undergoes a transition to the orthorhombic structure of K4Zn(MoO4)3. The structure of K4Mn(MoO4)3 was determined from single crystal diffraction data (a=7.613, b=9.955, c=10.156 Å,α=92.28,β=106.66,γ=105.58°, Z=2, space group

Synthesis and crystal structure of new complex oxides K10M2+Mo7O27 (M2+ = Mg, Mn, Co)

P\bar 1

Synthesis and crystal structure analysis of binary molybdate CsNamoO4 · 2H2O

, R=0.030). In this compound, Mn has a higher coordination number (CN=5+1) than that of Zn inα-K4Zn(WO4)3 (CN=4+1). The main structural feature is pairs of MnO6 octahedra linked by the bridging MoO4 tetrahedra into ribbons stretching along the a axis. The structure is compared with related structures of binary molybdates and other members of the alluaudite family.

Crystal structure investigation of ternary molybdate K5(Mn0.5Zr1.5).(MoO4)6

General principles of arrangement are discussed and analyzed for 13 known structural types (families) of binary molybdates and tungstates of uni-and bivalent metals, which were classified according to the degree of condensation of M2+On polyhedral and MoO4 tetrahedral constructions. The structural features of some phases correlate with their ferroelectric, ion-conducting, and luminescent (laser) properties. We suggest crystallochemical criteria and mechanisms of distortion (ferroelectric) phase transitions in palmierites, langbeinites, and Rb4Mn(MoO4)3 and show the paths of ionic transport in phases with NaCo231(MoO4)3, alluaudite, and Na2Mg5(MoO4)6 structures. On the basis of the analysis performed, we outlined the compounds that are the most promising for the development of inorganic materials with efficient physical properties.

Synthesis, characterization, and x-ray structural study of binary lithium managanese(II) molybdate

New compounds, K10M2+ Mo7O27 (M2+ = Mg, Mn, Co), have been synthesized and characterized. The compounds have an original structure, as established for the first two phases (orthorhombic, space group Pnm21, Z = 2, a = 18353 and 18.402, b = 7.889 and 7.931, c = 10.566 and 10.604 å, R = 0.0345 and 0.0609, respectively). A specific feature of the structure is isolated clusters consisting of face-sharing MoO6 and M2+O6 octahedra, each of the latter having six MoO4 tetrahedra attached to it by vertices. The general pseudohexagonal motif of the structure of the phases is similar to that of glaserites.

Synthesis and X‐Ray Study of Single Crystals of K5(Cd0.5Zr1.5)(MoO4)6 Triple Molybdate

Three (5∶1∶3, 1∶1∶1, and 2∶1∶6) ternary phases were discovered in the K2MoO4−AMoO4−Zr(MoO4)2 system, where A is Mg or Mn. For A=Mg, we have synthesized 5∶1∶3 single crystals and determined their crystal structure from X-ray diffraction data (a CAD-4 automatic diffractometer, MoKα radiation, 1166 F(hkl), and R=0.026). The compound crystallizes in the trigonal system with space group R3c, a=10.576(1), c=37.511(3), Å, Z=6, dcalc=3.576, and dmsd=3.54 g/cm3. The structure is a three-dimensional composite framework of alternating Mo tetrahedra and (Mg, Zr) octahedra, which are linked via the common O vertices. Potassium atoms of three kinds are located in large framework cavities. Their polyhedra (ten-vertex polyhedra and a cubeoctahedron) are linked together by common faces and edges to form infinite zigzag columns of a large section. When solving the structure, we refined the composition of the crystals and the distribution of Mg2+ and Zr4+ cations in the M(1) and M(2) positions resulting in the formula above.

Crystal structures of the double molybdates Na4Cu(MoO4)3 and Na2Ni(MoO4)2, new representatives of the alluaudite family

Single crystals of CsNaMoO4 · 2H2O were synthesized, and the crystal structure of this compound was determined from X- ray diffraction data (SYNTEX P21 automatic diffractometer, MoKα radiation, 2252 reflections, R =0.037). Crystals are orthorhombic, space group P212121 with unit cell dimensions a =6.379(1), b =8.625(1), c =13.671(2) å, Z =4. The structure of the binary molybdate consists of continuous columns of face- sharing Na octahedra with attached MoO4 tetrahedra. The neighboring columns are linked by the Cs cations and the hydrogen bonds of the water molecules entering into the coordination polyhedra of the Na and Cs atoms.

Thallium magnum zirconium molybdate Tl5Mg0.5Zr1.5(MoO4)6: Synthesis, crystal structure, and properties

Crystals of K(Mg0.5Zr0.5).(MoO4)2 were grown, and the composition and crystal structure of the compound were refined in an X-ray diffraction study (CAD-4 automatic diffractometer, MoKα radiation, 475 F(hkl), R=0.022). The parameters of the trigonal unit cell are: a=5.763(1); c=7.187(1) Å,Z=1, space group P3m1. A typical feature of a glaserite-like structure is atomic arrangement in two layers: at z=0 the Mg and Zr atoms are statistically distributed in the oxygen octahedra, and at z=0.5 the K atoms are distributed inside the icosahedra. In the second layer, Mo atoms with tetrahedral environment are also distributed.