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Thermal decomposition of brushite, CaHPO4·2H2O to monetite CaHPO4 and the formation of an amorphous phase

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Published/Copyright: April 2, 2015
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American Mineralogist
From the journal American Mineralogist Volume 96 Issue 2-3

Abstract

Brushite, CaHPO4∙2H2O, is a layered structure in which the layers are held together by water molecules via hydrogen bonds. Brushite loses its water molecules in two steps when heated, to form monetite CaHPO4. The loss of water results in the formation of an amorphous phase along with monetite. We investigated the dehydration process primarily by means of X-ray diffraction, and quantified the amount of monetite and the amorphous phase as a function of heating rate and temperature via Rietveld refinements. Water loss was recorded by thermogravimetric analysis and the nature of the products was investigated by Fourier transform infrared spectroscopy. Recrystallization, water loss, and the formation of the amorphous phase depend on the heating rate and/or time of exposure at temperature. The conversion temperature is about 220°C, although brushite can convert to monetite at lower temperatures during prolonged exposure to heat. More amorphous phase forms during slower dehydration at slower heating rates. The amorphous phase forms due to non-linear dehydration of brushite. The amorphous phase is hydrated and can be regarded as a highly disordered monetite with some free water trapped in the structure

Keywords: Brushite (DCPD); Monetite (DCPA); thermal analysis; amorphous calcium phosphate (ACP); XRD; TGA
Received: 2010-3-3
Accepted: 2010-10-2
Published Online: 2015-4-2
Published in Print: 2011-2-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Paulscherrerite from the Number 2 Workings, Mount Painter Inlier, Northern Flinders Ranges, South Australia: “Dehydrated schoepite” is a mineral after all
  2. Atomistic investigation of the pyrophyllitic substitution and implications on clay stability
  3. Application of the two-feldspar geothermometer to ultrahigh-temperature (UHT) rocks in the Khondalite belt, North China craton and its implications
  4. Wüstite in a hydrothermal silver-lead-zinc vein, Lucky Friday mine, Coeur d’Alene mining district, U.S.A.
  5. Gelosaite, BiMo6+(2–5x)Mo5+6xO7(OH)·H2O (0 ≤ x ≤ 0.4), a new mineral from Su Senargiu (CA), Sardinia, Italy, and a second occurrence from Kingsgate, New England, Australia
  6. Improved electron probe microanalysis of trace elements in quartz
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  8. Transmission electron microscopy investigation of Ag-free lillianite and heyrovskýite from Vulcano, Aeolian Islands, Italy
  9. Combined inelastic neutron scattering and solid-state density functional theory study of dynamics of hydrogen atoms in muscovite 2M1
  10. Contact metamorphism of a Cretaceous accretionary prism by the 14 Ma Okueyama granite, a single post-kinematic pluton in Central Kyushu, Japan: SVD analysis of metamorphic reactions and thermal release
  11. Origin of crosscutting dissolution surfaces in magmatic plagioclase
  12. Néel transition in (Mg,Fe)O: A possible change of magnetic structure
  13. Extreme channelization of fluid and the problem of element mobility during Barrovian metamorphism
  14. The high-temperature P21/m → C2/m phase transitions in synthetic amphiboles along the richterite–(BMg)–richterite join
  15. The crystal structure of barite, BaSO4, at high pressure
  16. Thermal decomposition of brushite, CaHPO4·2H2O to monetite CaHPO4 and the formation of an amorphous phase
  17. Rhombic-shaped nanodomains in columbite driven by contrasting cation order
  18. High-pressure structural evolution and equation of state of analbite
  19. In-situ dehydration studies of fully K-, Rb-, and Cs-exchanged natrolites
  20. The crystal structures and Raman spectra of aravaipaite and calcioaravaipaite
  21. Temperature dependence of the Fe2+ Mössbauer parameters in triphylite (LiFePO4)
  22. Synthesis and characterization of françoisite-(Nd): Nd[(UO2)3O(OH)(PO4)2]·6H2O
  23. Fluorphosphohedyphane, Ca2Pb3(PO4)3F, the first apatite supergroup mineral with essential Pb and F
  24. A new mineral with an olivine structure and pyroxene composition in the shock-induced melt veins of Tenham L6 chondrite
  25. The WURM project—a freely available web-based repository of computed physical data for minerals
  26. Acid production by FeSO4·nH2O dissolution: Comment
  27. Letter. Crystal chemistry of sodium in the Earth’s interior: The structure of Na2MgSi5O12 synthesized at 17.5 GPa and 1700 °C
  28. Letter. In-situ infrared spectra of OH in olivine to 1100°C
https://doi.org/10.2138/am.2011.3544
Keywords for this article
Brushite (DCPD); Monetite (DCPA); thermal analysis; amorphous calcium phosphate (ACP); XRD; TGA

Articles in the same Issue

  1. Paulscherrerite from the Number 2 Workings, Mount Painter Inlier, Northern Flinders Ranges, South Australia: “Dehydrated schoepite” is a mineral after all
  2. Atomistic investigation of the pyrophyllitic substitution and implications on clay stability
  3. Application of the two-feldspar geothermometer to ultrahigh-temperature (UHT) rocks in the Khondalite belt, North China craton and its implications
  4. Wüstite in a hydrothermal silver-lead-zinc vein, Lucky Friday mine, Coeur d’Alene mining district, U.S.A.
  5. Gelosaite, BiMo6+(2–5x)Mo5+6xO7(OH)·H2O (0 ≤ x ≤ 0.4), a new mineral from Su Senargiu (CA), Sardinia, Italy, and a second occurrence from Kingsgate, New England, Australia
  6. Improved electron probe microanalysis of trace elements in quartz
  7. Ultra-high residual compressive stress (>2 GPa) in a very small volume (<1 μm3) of indented quartz
  8. Transmission electron microscopy investigation of Ag-free lillianite and heyrovskýite from Vulcano, Aeolian Islands, Italy
  9. Combined inelastic neutron scattering and solid-state density functional theory study of dynamics of hydrogen atoms in muscovite 2M1
  10. Contact metamorphism of a Cretaceous accretionary prism by the 14 Ma Okueyama granite, a single post-kinematic pluton in Central Kyushu, Japan: SVD analysis of metamorphic reactions and thermal release
  11. Origin of crosscutting dissolution surfaces in magmatic plagioclase
  12. Néel transition in (Mg,Fe)O: A possible change of magnetic structure
  13. Extreme channelization of fluid and the problem of element mobility during Barrovian metamorphism
  14. The high-temperature P21/m → C2/m phase transitions in synthetic amphiboles along the richterite–(BMg)–richterite join
  15. The crystal structure of barite, BaSO4, at high pressure
  16. Thermal decomposition of brushite, CaHPO4·2H2O to monetite CaHPO4 and the formation of an amorphous phase
  17. Rhombic-shaped nanodomains in columbite driven by contrasting cation order
  18. High-pressure structural evolution and equation of state of analbite
  19. In-situ dehydration studies of fully K-, Rb-, and Cs-exchanged natrolites
  20. The crystal structures and Raman spectra of aravaipaite and calcioaravaipaite
  21. Temperature dependence of the Fe2+ Mössbauer parameters in triphylite (LiFePO4)
  22. Synthesis and characterization of françoisite-(Nd): Nd[(UO2)3O(OH)(PO4)2]·6H2O
  23. Fluorphosphohedyphane, Ca2Pb3(PO4)3F, the first apatite supergroup mineral with essential Pb and F
  24. A new mineral with an olivine structure and pyroxene composition in the shock-induced melt veins of Tenham L6 chondrite
  25. The WURM project—a freely available web-based repository of computed physical data for minerals
  26. Acid production by FeSO4·nH2O dissolution: Comment
  27. Letter. Crystal chemistry of sodium in the Earth’s interior: The structure of Na2MgSi5O12 synthesized at 17.5 GPa and 1700 °C
  28. Letter. In-situ infrared spectra of OH in olivine to 1100°C
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