Home Physical Sciences Coralloite, Mn2+Mn23+(AsO4)2(OH)2·4H2O, a new mixed valence Mn hydrate arsenate: Crystal structure and relationships with bermanite and whitmoreite mineral groups
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Coralloite, Mn2+Mn23+(AsO4)2(OH)2·4H2O, a new mixed valence Mn hydrate arsenate: Crystal structure and relationships with bermanite and whitmoreite mineral groups

  • Athos Maria Callegari EMAIL logo , Massimo Boiocchi , Marco E. Ciriotti and Corrado Balestra
Published/Copyright: April 2, 2015
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American Mineralogist
From the journal American Mineralogist Volume 97 Issue 4

Abstract

Coralloite is a new mineral found at the Monte Nero Mine (Rocchetta Vara, La Spezia, Liguria, Italy) having the simplified formula Mn2+Mn23+(AsO4)2(OH)2·4H2O. It occurs as sub-millimetric lamellar cinnabar-red crystals elongated on [100] and flattened on (001), isolated or forming wisps up to 0.5-1 mm long. Associated phases are calcite, inesite, quartz, brandtite, sarkinite, and tilasite in a chert matrix.

Crystals are pleochroic, yellow along [100] and orange-red in directions normal to it. Extinction is parallel to the cleavage traces and elongation is negative. The small crystal size does not allow accurate determination of refraction indices. Crossed polar observations of crystals placed in diiodomethane (n = 1.74) suggest that the mean refractive index is close to that value.

Coralloite is triclinic, space group P1, a = 5.5828(7), b = 9.7660(13), c = 5.5455(7) Å, α = 94.467(3), β = 111.348(2), γ = 93.850(2)°, V = 279.26(6) Å3, Z = 1. The five strongest lines in the simulated powder diffraction pattern (dobs, I, hkl) are: 9.710 Å, 100.0, (01̄0), 5.166 Å, 77.1, (100); 5.136 Å, 79.7, (001); 3.342 Å, 64.8, (1̄2̄1); 3.324 Å, 33.6, (12̄1̄).

The structure of coralloite (final Rall 0.044 for 3092 observed reflections) shows similarities with bermanite: Mn2+Mn23+(PO4)2(OH)2·4H2O and ercitite: Na2Mn23+(PO4)2(OH)2·4H2O. In particular, these three minerals exhibit the same structural slab formed by [[6]Mn23+([4]XO4)2(OH)2]; X = As or P. However, these structural slabs are connected by interposed layers of different polyhedra for each mineral species.

Keywords: Coralloite; bermanite; arsenates; structure refinement; Monte Nero area; Liguria
Received: 2011-5-10
Accepted: 2011-11-21
Published Online: 2015-4-2
Published in Print: 2012-4-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Veatchite: Structural relationships of the three polytypes
  2. Falsterite, Ca2MgMn2+2 (Fe2+0.5Fe3+0.5)4Zn4(PO4)8(OH)4(H2O)14, a new secondary phosphate mineral from the Palermo No. 1 pegmatite, North Groton, New Hampshire
  3. Pavlovskyite Ca8(SiO4)2(Si3O10): A new mineral of altered silicate-carbonate xenoliths from the two Russian type localities, Birkhin massif, Baikal Lake area and Upper Chegem caldera, North Caucasus
  4. Zaccagnaite-3R, a new Zn-Al hydrotalcite polytype from El Soplao cave (Cantabria, Spain)
  5. Incorporation of Si into TiO2 phases at high pressure
  6. TOF-SIMS and electron microprobe investigations of zoned magmatic orthopyroxenes: First results of trace and minor element analysis with implications for diffusion modeling
  7. Titanium in muscovite, biotite, and hornblende: Modeling, thermometry, and rutile activities of metapelites and amphibolites
  8. Polysaccharide-catalyzed nucleation and growth of disordered dolomite: A potential precursor of sedimentary dolomite
  9. High-pressure and high-temperature phase transitions in FeTiO3 and a new dense FeTi3O7 structure
  10. Compressibility and thermal expansion of hydrous ringwoodite with 2.5(3) wt% H2O
  11. Vibrational and elastic properties of ferromagnesite across the electronic spin-pairing transition of iron
  12. Electronic spin states of ferric and ferrous iron in the lower-mantle silicate perovskite
  13. Experimental VNIR reflectance spectroscopy of gypsum dehydration: Investigating the gypsum to bassanite transition
  14. Nature of rehydroxylation in dioctahedral 2:1 layer clay minerals
  15. Thermal behavior of afghanite, an ABABACAC member of the cancrinite group
  16. Experimental incorporation of Th into xenotime at middle to lower crustal P-T utilizing alkali-bearing fluids
  17. Sol-gel synthesis of nanocrystalline fayalite (Fe2SiO4)
  18. The heat capacity of fayalite at high temperatures
  19. Structural trends for celestite (SrSO4), anglesite (PbSO4), and barite (BaSO4): Confirmation of expected variations within the SO4 groups
  20. The dehydroxylation of serpentine group minerals
  21. Formation of nanoscale Th-coffinite
  22. Magnetic and low-temperature structural behavior of clinopyroxene-type FeGeO3: A neutron diffraction, magnetic susceptibility, and 57Fe Mössbauer study
  23. Crystal structure and thermal expansion of aragonite-group carbonates by single-crystal X-ray diffraction
  24. The lower-pressure stability of glaucophane in the presence of paragonite and quartz in the system Na2O-MgO-Al2O3-SiO2-H2O
  25. Coralloite, Mn2+Mn23+(AsO4)2(OH)2·4H2O, a new mixed valence Mn hydrate arsenate: Crystal structure and relationships with bermanite and whitmoreite mineral groups
  26. The crystal structure of metanatroautunite, Na[(UO2)(PO4)](H2O)3, from the Lake Boga Granite, Victoria, Australia
  27. Petedunnite (CaZnSi2O6): Stability and phase relations in the system CaO-ZnO-SiO2
  28. Revision of the crystal structure and chemical formula of weeksite, K2(UO2)2(Si5O13)·4H2O
  29. Electron backscatter diffraction (EBSD) analyses of phyllosilicates in petrographic thin sections
https://doi.org/10.2138/am.2012.3878
Keywords for this article
Coralloite; bermanite; arsenates; structure refinement; Monte Nero area; Liguria

Articles in the same Issue

  1. Veatchite: Structural relationships of the three polytypes
  2. Falsterite, Ca2MgMn2+2 (Fe2+0.5Fe3+0.5)4Zn4(PO4)8(OH)4(H2O)14, a new secondary phosphate mineral from the Palermo No. 1 pegmatite, North Groton, New Hampshire
  3. Pavlovskyite Ca8(SiO4)2(Si3O10): A new mineral of altered silicate-carbonate xenoliths from the two Russian type localities, Birkhin massif, Baikal Lake area and Upper Chegem caldera, North Caucasus
  4. Zaccagnaite-3R, a new Zn-Al hydrotalcite polytype from El Soplao cave (Cantabria, Spain)
  5. Incorporation of Si into TiO2 phases at high pressure
  6. TOF-SIMS and electron microprobe investigations of zoned magmatic orthopyroxenes: First results of trace and minor element analysis with implications for diffusion modeling
  7. Titanium in muscovite, biotite, and hornblende: Modeling, thermometry, and rutile activities of metapelites and amphibolites
  8. Polysaccharide-catalyzed nucleation and growth of disordered dolomite: A potential precursor of sedimentary dolomite
  9. High-pressure and high-temperature phase transitions in FeTiO3 and a new dense FeTi3O7 structure
  10. Compressibility and thermal expansion of hydrous ringwoodite with 2.5(3) wt% H2O
  11. Vibrational and elastic properties of ferromagnesite across the electronic spin-pairing transition of iron
  12. Electronic spin states of ferric and ferrous iron in the lower-mantle silicate perovskite
  13. Experimental VNIR reflectance spectroscopy of gypsum dehydration: Investigating the gypsum to bassanite transition
  14. Nature of rehydroxylation in dioctahedral 2:1 layer clay minerals
  15. Thermal behavior of afghanite, an ABABACAC member of the cancrinite group
  16. Experimental incorporation of Th into xenotime at middle to lower crustal P-T utilizing alkali-bearing fluids
  17. Sol-gel synthesis of nanocrystalline fayalite (Fe2SiO4)
  18. The heat capacity of fayalite at high temperatures
  19. Structural trends for celestite (SrSO4), anglesite (PbSO4), and barite (BaSO4): Confirmation of expected variations within the SO4 groups
  20. The dehydroxylation of serpentine group minerals
  21. Formation of nanoscale Th-coffinite
  22. Magnetic and low-temperature structural behavior of clinopyroxene-type FeGeO3: A neutron diffraction, magnetic susceptibility, and 57Fe Mössbauer study
  23. Crystal structure and thermal expansion of aragonite-group carbonates by single-crystal X-ray diffraction
  24. The lower-pressure stability of glaucophane in the presence of paragonite and quartz in the system Na2O-MgO-Al2O3-SiO2-H2O
  25. Coralloite, Mn2+Mn23+(AsO4)2(OH)2·4H2O, a new mixed valence Mn hydrate arsenate: Crystal structure and relationships with bermanite and whitmoreite mineral groups
  26. The crystal structure of metanatroautunite, Na[(UO2)(PO4)](H2O)3, from the Lake Boga Granite, Victoria, Australia
  27. Petedunnite (CaZnSi2O6): Stability and phase relations in the system CaO-ZnO-SiO2
  28. Revision of the crystal structure and chemical formula of weeksite, K2(UO2)2(Si5O13)·4H2O
  29. Electron backscatter diffraction (EBSD) analyses of phyllosilicates in petrographic thin sections
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