Search

Single crystals of KCo3Cu(As2.58V0.42)O12were prepared by solid state reactions below the melting point of the reaction mixture (K2CO3, CuO, COC2O4, V2O5and 3 As2O5· 5H2O). It crystallizes with monoclinic symmetry, space group C62h-C2/c, a = 12.207, b = 12.730, c = 6.811 Å, β = 113.69°, Z = 4. The structure type is characterized by isolated twisted-square CuO4-polygons, CoO6-octahedra and a special 4+4-coordination of the potassium ion. As5+ and V5+are in tetrahedral coordination with a partly statistical distribution of these ions.

Single crystals of the low (t-) and high (h-) temperature form of ZnOZn3(AsO4)2have been prepared by flux and by CO2-LASER techniques respectively. Both compounds crystal­lizes monoclinic, space group C52h-P21/n with the lattice parameters t-ZnOZn3(AsO4)2: a = 9.807(3), b = 8.180(2), c = 9.967(2) Å , β = 116.53(2)°, Z = 4 and h -ZnOZn3(AsO4)2: a = 9.743(3), b = 8.163(8), c = 17.933(2) Å , β = 91.55(2)°, Z = 8. Similarities and differences of the crystal structures will be discussed.

Single crystals of CuO(Cu,Mg)3[(As0.7P0.3)O4]2have been prepared by crystallization from melts. The compound crystallizes with triclinic symmetry, space group Ci1-P1̄, a = 6.372(4), b = 7.643(7), c = 8.175(5) Å, α = 98.59(6), β = 112.26(3), γ = 99.03(3)°, Z = 2. CuO(Cu,Mg)3[(As0.7P0.3)O4]2is isotypic to Cu4(PO4)2O . X-ray investigations show square planar CuO4polygons, twisted tetragonal CuO5pyramids, CuO5bipyramids and elongated (Cu,Mg)O6octahedra.

Single crystals of KMg3Pd (AsO4)3have been p repared by solid state reactions below the melting point of the reaction mixture. This compound crystallizes isotypic to the mineral Johilleriteo with monoclinic symmetry, space group C 2h6 -C 2/c , a = 12.098(3) Å, b = 12.853(5) Å , c = 6.688(3) Å, β = 112.92(3)°, Z = 4. The crystal structure is characterized by AsO4tetrahedra, isolated planar but twisted PdO4polygons, MgO6octahedra and a 2+4+2- coordination of potassium . From the point of view of crystal chemistry KMg3Pd (AsO4)3both belongs to the arsenates and oxopalladates(II).

Presents the poem "The Hackberry Hills," by D. C. Frerichs.