C. Langereis

Compounds in the system BaOY2O3

Abstract Starting with BaO and Y 2 O 3 , four compounds are found in the BaOY 2 O 3 system. At high temperatures (above 1200°C) two compounds mentioned in literature are found: Ba 3 Y 4 O 9 and BaY 2 O 4 . Heating the oxidic mixtures at 900°C results in the formation of a new compound Ba 2 Y 2 O 5 . This compound is transformed at 1000°C into another new compound: Ba 4 Y 2 O 7 . X-ray data of the four compounds are given in detail.

Hydrates of manganese (II) oxalate

Abstract In addition to the monoclinic ∝-dihydrate, it has now proved possible to prepare a second dihydrate, hitherto unknown. This compound, having an orthorhombic unit cell, proves to be the more stable modification of the dihydrates. For the trihydrate as well as for the anhydrous salt, orthorhombic unit cells were found. Prescriptions for the preparation of each of the hydrates are given. Some details are added about particle size, thermal decomposition and stability of the compounds, together with crystallographic and X-ray data.

Compounds in the system BaO In2O3

Abstract The occurrence of compounds in the system BaOIn2O3 has been investigated. In addition to the already known compounds BaIn2O4 and Ba4In6O13, three new compounds were found: Ba2In2O5, Ba3In2O6 and Ba5In2O8. Ba2In2O5 has a simple, perovskite-like X-ray diagram, which however, could not be indexed. Ba3In2O6 and Ba5In2O8 have tetragonal body-centered unit cells with a = 4.1913 A , c = 21.6693 A and a = 4.1742 A , c = 29.431 A respectively. Ba3In2O6 reacts with most air to form a hydrogarnet: Ba3In2(OH)12.

Compounds in the system BaOSc2O3

Abstract The occurrence of compounds in the system BaOIn2O3 has been investigated. In addition to the already known compounds BaIn2O4 and Ba4In6O13, three new compounds were found: Ba2In2O5, Ba3In2O6 and Ba5In2O8. Ba2In2O5 has a simple, perovskite-like X-ray diagram, which however, could not be indexed. Ba3In2O6 and Ba5In2O8 have tetragonal body-centered unit cells with a = 4.1913 A , c = 21.6693 A and a = 4.1742 A , c = 29.431 A respectively. Ba3In2O6 reacts with most air to form a hydrogarnet: Ba3In2(OH)12.

Triode-Sputtered High-Tc Superconducting Thin Films

High-Tc superconducting thin films were prepared by DC sputtering. Contrary to diode sputter methods, in the triode configuration applied here no compositional adjustment of the ceramic YBa2Cu3Ox target appeared necessary. SrTiO3 (100) was the best substrate found so far. After an onset at Tco = 92 K, we found a complete superconductive transition at Tcf = 86 K. At the transition a five-order decrease in resistivity could be measured. On other substrates such as Al2O3, MgO and ZrO2 relatively poor results were obtained. Characterization was performed by SEM, x-ray diffraction and Rutherford backscattering (RBS).

Basic lead nitrates

Abstract The phases in the system Pb(NO 3 ) 2 -Pb(OH) 2 were investigated by X-ray diffraction methods. Four one-phase products were found: Pb(NO 3 ) 2 ·Pb(OH) 2 ; 2Pb(NO 3 ) 2 ·5Pb(OH) 2 ; Pb(NO 3 ) 2 ·3Pb(OH) 2 and Pb(NO 3 ) 2 ·5Pb(OH) 2 . The compound Pb(NO 3 ) 2 ·3Pb(OH) 2 can be prepared only in more dilute solutions. The composition of these compounds was confirmed by chemical analysis. When the compounds are heated up to 300°C, some water is lost and the X-ray diagrams are changed, but the Pb:NO 3 ratio does not alter essentially. The interplanar spacings and the X-ray intensities of the four basic lead nitrates are given.

The formation of YBa3Ti2O8.5 in the reaction of YBa2Cu3O7 with SrTiO3

Abstract The solid state reaction in air of the high temperature superconductor YBa2Cu3O7 with SrTiO3 was investigated at temperatures from 850°C to 950°C. The solid reaction products were characterized by XRD. A new compound YBa3Ti2O8.5 was identified. YBa3Ti2O8.5 crystallizes in a hexagonal unit cell with a=5.928 A and c=29.514 A. A list of interplanar 0 spcings and hkl indices as determined from powder X-ray diffraction measurements are presented.

Basic lead acetates

Abstract The occurrence of basic lead acetates was investigated by X-ray diffraction diagrams taken from dried samples of lead acetate-lead oxide reaction mixtures. Two compounds were found: 3Pb(CH 3 COO) 2 ·PbO·H 2 O and Pb(CH 3 COO) 2 ·2PbO·H 2 O. A compound Pb(CH 3 COO) 2 ·PbO was not detected. The interplanar spacings and X-ray intensities for the two basic acetates are given. The data for anhydrous lead acetate, Pb(CH 3 COO) 2 , are included.

Alkaline earth scandates

In the CaOSrOSc2O3 and BaOSrOSc2O3 systems, complete series of mixed crystals were found for (Ca,Sr)Sc2O4 and (Sr,Ba)3Sc4O9 respectively. In the BaOCaOSc2O3 system a new ternary phase with composition Bax(Ca2xSc2−2x)Sc6O12 was detected having an incommensurate structure which may be described with a basic hexagonal unit cell (a=9.7039 A, c=3.1274 A) and a second hexagonal cell having the same basic a-axis. The c-axis of the second cell is x-dependent: cx = 3.13/x A, x varying from 0.782 to 0.736, corresponding to the region from BaCa2Sc8O15 with cx = 4.00 A, to BaCa2Sc9O16.5 with cx = 4.25 A.