Letter. Crystal structure of uchucchacuaite, AgMnPb3Sb5S12, and its relationship with ramdohrite and fizélyite
-
H. Yang
Abstract
Uchucchacuaite, ideally AgMnPb3Sb5S12, was originally reported as orthorhombic, with possible space group Pmmm, P222, or Pmm2, and unit-cell parameters a = 12.67, b = 19.32, and c = 4.38 Å obtained from powder X‑ray diffraction data (Moëlo et al. 1984a). Using single-crystal X‑ray diffraction, we examined two uchucchacuaite samples, one from the type locality, Uchucchacua, Peru, and the other from Hokkaido, Japan (designated as R100213 and R070760, respectively). Our results show that uchucchacuaite is isostructural with ramdohrite and fizélyite, with monoclinic symmetry (P21/n) and the unit-cell parameters a = 19.3645(11), b = 12.7287(8), c = 8.7571(6) Å, β = 90.059(3)° for R100213 and a = 19.3462(7), b = 12.7251(5), c = 8.7472(3) Å, β = 90.017(2)° for R070760. Both samples are pervasively twinned and the twin refinements yielded the final R1 factors of 0.037 and 0.031 for R100213 and R070760, respectively. The chemical compositions determined from electron microprobe analysis are Ag0.99(Mn0.92Pb0.03Sb0.02Bi0.01)Σ=0.98Pb3.00Sb5.00S12.00 for R100213 and Ag1.00(Mn0.82Sb0.11Ag0.04Bi0.02)Σ=0.99Pb2.98Sb5.00S12.00 for R070760. The key structural difference among uchucchacuaite, ramdohrite, and fizélyite lies in the cations occupying the M2 site, which can be expressed with a general structural formula as Ag(M2+2yAg½-ySb½-y)Pb3Sb5S12, where M2+ represents divalent cations with 0 ≤ y ≤ ½. From the current list of IMA-defined minerals, we consider M = Cd with y = 0.125 for ramdohrite, M = Pb with y = 0.25 for fizélyite, and M = Mn with y = 0.5 for uchucchacuaite. Associated with the variation in the average M2 cation size from fizélyite (1.078 Å) to ramdohrite (0.955 Å) and uchucchacuaite (0.83 Å) is the significant decrease in the average M2-S bond distance from 2.917 to 2.834, and 2.654 Å, respectively, as well as corresponding variations in the unit-cell b dimension from ~13.23 to 13.06 and 12.73 Å.
© 2015 by Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Needs and opportunities in mineral evolution research
- Rutile inclusions in quartz crystals record decreasing temperature and pressure during the exhumation of the Su-Lu UHP metamorphic belt in Donghai, East China
- A first-principles study of the phase transition from Holl-I to Holl-II in the composition KAlSi3O8
- Sejkoraite-(Y), a new member of the zippeite group containing trivalent cations from Jáchymov (St. Joachimsthal), Czech Republic: Description and crystal structure refinement
- Thermoelastic and thermodynamic properties of plagioclase feldspars from thermal expansion measurements
- Quantitative determination of chrysotile in massive serpentinites using DTA: Implications for asbestos determinations
- In situ observation of the crystallization pressure induced by halite crystal growth in a microfluidic channel
- Microstructures of the larval shell of a pearl oyster, Pinctada fucata, investigated by FIB-TEM technique
- Magnesium quantification in calcites [(Ca,Mg)CO3] by Rietveld-based XRD analysis: Revisiting a well-established method
- The effect of Fe on olivine H2O storage capacity: Consequences for H2O in the martian mantle
- Kinetics of thermal transformation of partially dehydroxylated pyrophyllite
- Dehydration of the natural zeolite goosecreekite CaAl2Si6O16·5H2O upon stepwise heating: A single-crystal and powder X-ray study
- Incorporation mechanisms of Ta and Nb in zircon and implications for pegmatitic systems
- Variable-temperature 27Al and 29Si NMR studies of synthetic forsterite and Fe-bearing Dora Maira pyrope garnet: Temperature dependence and mechanisms of paramagnetically shifted peaks
- Calibrating Ti concentrations in quartz for SIMS determinations using NIST silicate glasses and application to the TitaniQ geothermobarometer
- Crystal structure of Na3Fe(SO4)3: A high-temperature product (∼400 °C) of sideronatrite [Na2Fe(SO4)2OH⋅3H2O]
- Evidence for boron incorporation into the serpentine crystal structure
- Structure refinement of Ag-free heyrovskýite from Vulcano (Aeolian Islands, Italy)
- Microtextures, microchemistry, and mineralogy of basaltic glass alteration, Jeju Island, Korea, with implications for elemental behavior
- Orientation of channel carbonate ions in apatite: Effect of pressure and composition
- Thermoelastic property and high-pressure stability of Fe7C3: Implication for iron-carbide in the Earth’s core
- Yttriaite-(Y): The natural occurrence of Y2O3 from the Bol’shaya Pol’ya River, Subpolar Urals, Russia
- Identification and characterization of nanosized tripuhyite in soil near Sb mine tailings
- Letter. High-pressure I2/c-P21/c phase transformation in SrAl2Si2O8 feldspar
- Letter. Crystal structure of uchucchacuaite, AgMnPb3Sb5S12, and its relationship with ramdohrite and fizélyite
Artikel in diesem Heft
- Needs and opportunities in mineral evolution research
- Rutile inclusions in quartz crystals record decreasing temperature and pressure during the exhumation of the Su-Lu UHP metamorphic belt in Donghai, East China
- A first-principles study of the phase transition from Holl-I to Holl-II in the composition KAlSi3O8
- Sejkoraite-(Y), a new member of the zippeite group containing trivalent cations from Jáchymov (St. Joachimsthal), Czech Republic: Description and crystal structure refinement
- Thermoelastic and thermodynamic properties of plagioclase feldspars from thermal expansion measurements
- Quantitative determination of chrysotile in massive serpentinites using DTA: Implications for asbestos determinations
- In situ observation of the crystallization pressure induced by halite crystal growth in a microfluidic channel
- Microstructures of the larval shell of a pearl oyster, Pinctada fucata, investigated by FIB-TEM technique
- Magnesium quantification in calcites [(Ca,Mg)CO3] by Rietveld-based XRD analysis: Revisiting a well-established method
- The effect of Fe on olivine H2O storage capacity: Consequences for H2O in the martian mantle
- Kinetics of thermal transformation of partially dehydroxylated pyrophyllite
- Dehydration of the natural zeolite goosecreekite CaAl2Si6O16·5H2O upon stepwise heating: A single-crystal and powder X-ray study
- Incorporation mechanisms of Ta and Nb in zircon and implications for pegmatitic systems
- Variable-temperature 27Al and 29Si NMR studies of synthetic forsterite and Fe-bearing Dora Maira pyrope garnet: Temperature dependence and mechanisms of paramagnetically shifted peaks
- Calibrating Ti concentrations in quartz for SIMS determinations using NIST silicate glasses and application to the TitaniQ geothermobarometer
- Crystal structure of Na3Fe(SO4)3: A high-temperature product (∼400 °C) of sideronatrite [Na2Fe(SO4)2OH⋅3H2O]
- Evidence for boron incorporation into the serpentine crystal structure
- Structure refinement of Ag-free heyrovskýite from Vulcano (Aeolian Islands, Italy)
- Microtextures, microchemistry, and mineralogy of basaltic glass alteration, Jeju Island, Korea, with implications for elemental behavior
- Orientation of channel carbonate ions in apatite: Effect of pressure and composition
- Thermoelastic property and high-pressure stability of Fe7C3: Implication for iron-carbide in the Earth’s core
- Yttriaite-(Y): The natural occurrence of Y2O3 from the Bol’shaya Pol’ya River, Subpolar Urals, Russia
- Identification and characterization of nanosized tripuhyite in soil near Sb mine tailings
- Letter. High-pressure I2/c-P21/c phase transformation in SrAl2Si2O8 feldspar
- Letter. Crystal structure of uchucchacuaite, AgMnPb3Sb5S12, and its relationship with ramdohrite and fizélyite
