Dear Matthew I am not sure but using the cell parameters you gave and the restriction that Ca and Al must be contained in the structure gives only 1 entry in ICSD. The fluorowardite, as published here: https://www.degruyter.com/document/doi/10.2138/am.2014.4663/html
The structure would be ICSD-#248383 - NaAl3(PO4)2(OH)2F2·2H2O Though it seems that the structure you search would need a doubled unit cell volume to fit the given stoichiometry (which seems like a doubled form of the wardite/fluorowardite) Maybe one could use a subgroup to get that? Merry Christmas and a happy new year Stefan Seidlmayer Am Di., 24. Dez. 2024 um 04:49 Uhr schrieb Matthew Rowles < rowle...@gmail.com>: > Hi all > > Does anyone know of a published crystal structure for millisite? > > It is nominally (Na,K)CaAl6(PO4)4(OH)9·3H2O > Tetragonal, a=7, c=19.07 Å > See http://www.minsocam.org/ammin/AM45/AM45_547.pdf > > > or maybe anything possibly isostructural/morphous? It's pretty close to > wardite, but has an extra hydroxide and water. > > ICDD PDF4+ has nothing, Various searches on COD haven't revealed anything. > I don't have access to ICSD. > > Thanks > > > Matthew Rowles > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com > > > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body > text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > >
ICSD_CollCode248383.cif
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++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
