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Beraunite: Refinement, comparative crystal chemistry, and selected bond valences

Published/Copyright: August 24, 2010
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Zeitschrift für Kristallographie - Crystalline Materials
From the journal Zeitschrift für Kristallographie - Crystalline Materials Volume 201 Issue 3-4

Abstract

Deep green beraunite from Campanian age marls of Mullica Hill, N. J. (USA) was investigated owing to its unique crytal chemistry (two previous refinements involved orange crystals). Our crystal gave nearly 4[Fe2+Fe53+(OH)5(H2O)4(PO4)4 · 2H2O], a = 20.953(5), b = 5.171(1), c = 19.266(4) Å, β = 93.34(2)°, C2/c, R = 0.043 (isotropic) for 2065 unique Fo and 91 variable parameters.

Common to several known “ferrosoferric” phosphate structures, the underlying principle is a linear face-sharing oxygen octahedral trimer whose cations are M(4) – M(1) – M(4). For our beraunite, ca. 83% Fe2+ resides in the central M(1) site with mean M(1) – O = 2.11 Å. The other octahedral cation sites M(2), M(3), and M(4) (mean M – O distances 2.01 to 2.02 Å) are Fe3+. The orange crystals of the other studies have predominant Fe3+ at all M(1) to M(4) octahedral sites (mean M – O distances 1.97 to 2.04 Å). Distortion of the octahedral face-trimer is pronounced, with M(1) – M(4) distance lengthening of 19% compared with the perfect octahedral model. This results from cation-cation repulsion, which distorts the entire immediate environment from the perfect model.

The OH(1) site on the trimer is coordinated by M(1), M(3), M(4), and H(1). Bond valence computations for the trimer suggest that Fe2+ Fe3+ (green) → Fe3+ Fe3+ (orange) may involve (1) O – H(1) distance response to bond valence deviation or (2) an averaged model 2OH−→2(OH½O½)1.5−, but independent spectroscopic study is required to unravel the mechanism.

Published Online: 2010-8-24
Published in Print: 1992-2-1

© 2015 Oldenbourg Wissenschaftsverlag GmbH, Rosenheimer Str. 145, 81671 München

Articles in the same Issue

  1. Crystal structure of a magnesium chloride-ethylformate adduct
  2. The crystal structure of triethylenetetramine copper(II)fluorophosphate, Cu(trien)(PF6)2
  3. Crystal structure of mesogenic material – trans-4-propyl cyclohexyl-4-(trans-4-pentyl cyclohexyl) benzoate
  4. The role of OH and H2O in oxide and oxysalt minerals
  5. Redetermination of the crystal structure of diammine silver(I)-sulfate, [Ag(NH3)2]2SO4
  6. Geometrische und chemische Koordination
  7. Reppiaite, Mn5(OH)4(VO4)2, a new mineral from Val Graveglia (Northern Apennines, Italy)
  8. Crystal structures and crystal chemistry of compounds M5−pT4+pO14*
  9. Crystal chemistry of beryllophosphates: The crystal structure of moraesite, Be2(PO4)(OH) · 4H2O
  10. Beraunite: Refinement, comparative crystal chemistry, and selected bond valences
  11. Crystal structure of thallium tetrafluoroborate, TlBF4
  12. Crystal structure of (η3-syn-crotyl)-(η4-cycloocta-1,5-diene)-nickel(II) hexafluorophosphate, Ni(C8H12)(C4H7)PF6
  13. Crystal structure of (η8-cycloocta-l,3,5,7-tetraene)-(2,2′-dipyridyl)-titanium(I) chloride, Ti(C8H8)(C10H8N2)Cl
  14. Crystal structure of (η3-syn-crotyl)-(η4-cycloocta-1,5-diene)-nickel(II) trifluormethylsulfonate, Ni(C12H19)(SO2CF3)
  15. Crystal structure of μ-hydrido-μ-dicyclohexylphosphido-octacarbonyl-dirhenium, (H)(P(C6H11)2)(CO)8Re2
  16. Crystal structure of μ-dicyclohexylphosphido-dodecacarbonyl-triangulo-trirhenium, (P(C6H11)2)(Re(CO)4)3
  17. Crystal structure of di-μ3-[(pentacarbonyl-manganese)stannio(IV)]-nonacarbonyl-triangulotriiron(Fe-Fe), (SnMn(CO)5)2Fe3(CO)9
  18. Crystal structure of calcium gold aluminium (1/1/1), CaAuAl
  19. Crystal structure of calcium gold aluminium (1/0.9/3.1), CaAu0.9Al3.1
  20. Crystal structure of barium gold gallium (1/0.3/3.7), BaAu0.3Ga3.7
  21. Crystal structure of strontium gold gallium (1/1/3), SrAuGa3
  22. Crystal structure of calcium cadmium gallium (1/0.7/1.3), CaCd0.7Ga1.3
  23. Crystal structure of strontium cadmium gallium (1/1.3/0.7), SrCd1.3Ga0.7
  24. Crystal structure of strontium cadmium gallium (1/2/2), SrCd2Ga2
  25. Crystal structure of barium cadmium gallium (1/3.2/0.8), BaCd3.2Ga0.8
  26. Crystal structure of N-diphenylphosphine-l-amino-3-(2′-pyridyl)-isoquinoline-chloropalladium(II) chloride chloroform methanol solvate, (P(C6H5)2)(C9N2H6)(C5NH4)(PdCl)Cl(CHCl3)(CH3OH)
  27. Crystal structure of μ-dicyclohexylphosphido-triphenylphosphine-octacarbonyl-triangulo-copperdirhenium, (P(C6H11)2)(CO)8Re2Cu(P(C6H5)3)
  28. Crystal structure of caesium rubidium di-μ-arsenidobis(arsenidogallate), Cs5.18Rb0.82Ga2As4
  29. Crystal structure of caesium rubidium di-μ-phosphido-bis(phosphidogallate), Cs4.95Rb1.05Ga2P4
https://doi.org/10.1524/zkri.1992.201.3-4.263

Articles in the same Issue

  1. Crystal structure of a magnesium chloride-ethylformate adduct
  2. The crystal structure of triethylenetetramine copper(II)fluorophosphate, Cu(trien)(PF6)2
  3. Crystal structure of mesogenic material – trans-4-propyl cyclohexyl-4-(trans-4-pentyl cyclohexyl) benzoate
  4. The role of OH and H2O in oxide and oxysalt minerals
  5. Redetermination of the crystal structure of diammine silver(I)-sulfate, [Ag(NH3)2]2SO4
  6. Geometrische und chemische Koordination
  7. Reppiaite, Mn5(OH)4(VO4)2, a new mineral from Val Graveglia (Northern Apennines, Italy)
  8. Crystal structures and crystal chemistry of compounds M5−pT4+pO14*
  9. Crystal chemistry of beryllophosphates: The crystal structure of moraesite, Be2(PO4)(OH) · 4H2O
  10. Beraunite: Refinement, comparative crystal chemistry, and selected bond valences
  11. Crystal structure of thallium tetrafluoroborate, TlBF4
  12. Crystal structure of (η3-syn-crotyl)-(η4-cycloocta-1,5-diene)-nickel(II) hexafluorophosphate, Ni(C8H12)(C4H7)PF6
  13. Crystal structure of (η8-cycloocta-l,3,5,7-tetraene)-(2,2′-dipyridyl)-titanium(I) chloride, Ti(C8H8)(C10H8N2)Cl
  14. Crystal structure of (η3-syn-crotyl)-(η4-cycloocta-1,5-diene)-nickel(II) trifluormethylsulfonate, Ni(C12H19)(SO2CF3)
  15. Crystal structure of μ-hydrido-μ-dicyclohexylphosphido-octacarbonyl-dirhenium, (H)(P(C6H11)2)(CO)8Re2
  16. Crystal structure of μ-dicyclohexylphosphido-dodecacarbonyl-triangulo-trirhenium, (P(C6H11)2)(Re(CO)4)3
  17. Crystal structure of di-μ3-[(pentacarbonyl-manganese)stannio(IV)]-nonacarbonyl-triangulotriiron(Fe-Fe), (SnMn(CO)5)2Fe3(CO)9
  18. Crystal structure of calcium gold aluminium (1/1/1), CaAuAl
  19. Crystal structure of calcium gold aluminium (1/0.9/3.1), CaAu0.9Al3.1
  20. Crystal structure of barium gold gallium (1/0.3/3.7), BaAu0.3Ga3.7
  21. Crystal structure of strontium gold gallium (1/1/3), SrAuGa3
  22. Crystal structure of calcium cadmium gallium (1/0.7/1.3), CaCd0.7Ga1.3
  23. Crystal structure of strontium cadmium gallium (1/1.3/0.7), SrCd1.3Ga0.7
  24. Crystal structure of strontium cadmium gallium (1/2/2), SrCd2Ga2
  25. Crystal structure of barium cadmium gallium (1/3.2/0.8), BaCd3.2Ga0.8
  26. Crystal structure of N-diphenylphosphine-l-amino-3-(2′-pyridyl)-isoquinoline-chloropalladium(II) chloride chloroform methanol solvate, (P(C6H5)2)(C9N2H6)(C5NH4)(PdCl)Cl(CHCl3)(CH3OH)
  27. Crystal structure of μ-dicyclohexylphosphido-triphenylphosphine-octacarbonyl-triangulo-copperdirhenium, (P(C6H11)2)(CO)8Re2Cu(P(C6H5)3)
  28. Crystal structure of caesium rubidium di-μ-arsenidobis(arsenidogallate), Cs5.18Rb0.82Ga2As4
  29. Crystal structure of caesium rubidium di-μ-phosphido-bis(phosphidogallate), Cs4.95Rb1.05Ga2P4
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