Abstract
We report data on the composition and crystal structure of the most Ag-rich (15.63 apfu) natural polybasite yet discovered. It shows the - M 2 a 2 b 2 c polytype. The crystal studied was found in a sample (mineralogical collection of the Royal Ontario Museum) from Gowganda, Timiskaming District, Ontario, Canada. Electron microprobe analysis yields the formula [Ag6(Sb1.78As0.18)∑=1.96S7] [Ag9(Ag0.63Cu0.43)∑=1.06S4]. Lattice parameters are a = 26.2625(4), b = 15.1623(5), c = 24.1061(6) A, β = 90.045(5)°, V = 9599.0(4) A3. The structure was refined in the space group C 2/ c to R = 0.0581 using 7725 observed reflections [ I > 2σ( I )]. The refinement shows that one of the three structural positions of the B module layer usually occupied by Cu is dominated by Ag. Crystal-chemical characteristics are compared with published data on the other members of the pearceite-polybasite group. Some remarks concerning nomenclature are also given.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
