Über eine Hilfsapparatur zur Messung der Lichtbrechung von hygroskopischen Pulvern

Abstract

Professor Franx Hein xum 60. Geburtstag gewidmet InhaltsubersichtEr wird eine Einbettungskamrner mit Stromungsvorrichtung beschrieben, rnit deren Hilfe die Lichtbrechung auch von hygroskopischen durchsichtigen Pulvern nach der BEcKEschen Methode unter dem Polarisationsinikroskop bestimmt werden kann.

The structure of zinc polyphosphate glass studied by diffraction methods and 31P NMR

“…5 reveal a shift of the main peak, but none of the curves possess a prepeak as frequently observed for phosphate glasses [42]. Reverse Monte Carlo simulations on the basis of diffraction data with high real-space resolution have shown [15] that the main peak of the SðsÞ function of the Zn metaphosphate sample mainly originates from the superposition of the Zn 2þ -PO 4 phosphate glass systems, a prepeak could be expected to be produced by the Zn 2þ -PO 4 -Zn 2þ correlations. For example, the pronounced prepeak observed in the SðsÞ function of La metaphosphate glass is mainly attributable to the La 3þ -PO 4 -La 3þ correlations [43].…”

“…Attributable to the unusual discontinuities in the composition-property dependence, Kordes et al [4] identified the zinc and magnesium phosphate system as Ôanomalous'. This unusual behavior was originally explained [4] by a coordination change of the Zn 2þ or Mg 2þ cation, respectively, from 4 to 6 at metaphosphate composition, but there was no experimental support for this explanation. As just shown, the Zn-O coordination number is invariant across the entire polyphosphate concentration range.…”

“…(III) For studying the structural specifics of phosphate glasses, the binary zinc phosphate system has proved to be very suitable [2,3]. Moreover, these glasses have been classified into the so-called anomalous phosphate glasses [4].…”

Structure and dissolution behavior of MgO–P₂O₅–TiO₂/Nb₂O₅ (Mg/P ≥ 1) invert glasses

“…Magnesium phosphate glasses exhibit unusual properties and were classified as 'anomalous phosphate glasses' by Kodrdes et al 1)3) The anomalous properties of magnesium phosphate glasses are attributed to the variation of the MgO coordination number from 6 to 4. 1) Many researchers have focused on MgO P 2 O 5 binary glasses and discussed their structures.…”

“…1) Many researchers have focused on MgO P 2 O 5 binary glasses and discussed their structures. 4)13) Magnesium in phosphate glasses acts as a network modifier and/or former depending on their composition, i.e., intermediate oxides: the role is determined by the phosphate chain length.…”