{"id":335,"date":"2018-04-22T21:45:53","date_gmt":"2018-04-22T19:45:53","guid":{"rendered":"http:\/\/localhost\/wordpress\/?page_id=335"},"modified":"2018-04-29T17:05:35","modified_gmt":"2018-04-29T15:05:35","slug":"harmonia","status":"publish","type":"page","link":"https:\/\/www.mba-group.agh.edu.pl\/?page_id=335","title":{"rendered":"Harmonia"},"content":{"rendered":"
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Title:<\/strong><\/em> Precise determination of solubility constants in 5 \u2013 65\u00baC temperature range and DHf, DGf, DS for apatites in of Ca-Pb-P-As-OH-Cl type.
\nDuration: <\/strong><\/em>2011-2014
\nPrincipal Investigator:<\/strong><\/em> Maciej Manecki
\nCo-Investigators: <\/em><\/strong>Tomasz Bajda, Jakub Matusik
\nFunding agency: <\/strong><\/em>National Science Centre (Poland)
\nProject ID: <\/strong><\/em>Harmonia<\/p>\n

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The major accomplishments of the Project are:<\/p>\n

– For the first time it was experimentally verified and confirmed that all apatites from solid solutions in question: a) hydrokxylpyromorphite Pb5(PO4)3(OH) \u2013 hydrokxylapatite Ca5(PO4)3(OH); b) hydroxylapatite Ca5(PO4)3(OH) \u2013 johnbaumite Ca5(AsO4)3(OH); and c) hydrokxylmimetite Pb5(AsO4)3(OH) \u2013 johnbaumite Ca5(AsO4)3(OH) can prezipitate stoichiometrically from aqueous solutions at normal environmental conditions.<\/p>\n

– A model explaining systematic shifts in vibrational spectra of isomorphic solid solutions was proposed (for Raman and Infra-red spectroscopy) based on the bond strength and bond length as well as average mass of atoms located at substituted structural positions. As it was hypothesized, the model is universal and holds for all apatites.<\/p>\n

– For the first time it was determined that in contrast to hexagonal crystalline structure of F- and Cl- varieties of Pb-apatites, their hydroxyl varieties are monoclinic. This is analogous to Ca-hydroxylapatites, but the effect on their stability (solubility) is opposite.<\/p>\n

– For the first time it was determined that the solubility of pyromorphite Pb5(PO4\u00ad)3Cl is endothermic and the Ksp depends on the temperature following the nonlinear trend. This allowed for experimental determination of specific heat of formation Cp for pyromorphite.<\/p>\n

– The role of carbonate substitution in Pb-apatites was precisely determined and correctly characterized, improving previously published results. For the first time the role of carbonates in arsenic lead apatites was described.<\/p>\n

– Formation of precursors to lead-phosphate and lead-arsenate apatites was determined and characterized, including their solid solutions, isostructual with shultenite PbHAsO4 and phosphoshultenite PbHPO4.<\/p>\n

Most important publications:<\/strong><\/p>\n