PMID- 22992792
OWN - NLM
STAT- MEDLINE
DCOM- 20121227
LR  - 20120920
IS  - 1600-5740 (Electronic)
IS  - 0108-7681 (Linking)
VI  - 68
IP  - Pt 5
DP  - 2012 Oct
TI  - Cl-OH ion-exchanging process in chlorapatite (Ca5(PO4)3Cl(x)(OH)(1-x))--a deep 
      insight.
PG  - 467-79
AB  - We have synthesized large chlorapatite [ClAp, Ca(5)(PO(4))(3)Cl(x)(OH)(1-x), 
      where x = 1] single crystals using the molten salt method. We have corroborated 
      that the hexagonal symmetry P6(3)/m describes the crystal structure best, even 
      though the crystals are synthetic and stoichiometric. Moreover, we have performed 
      several thermal treatments on these ClAp crystals, generating new single crystals 
      in the apatite system [Ca(5)(PO(4))(3)Cl(x)(OH)(1-x), where x </= 1], where the 
      chloride anions (Cl(-)) were systematically substituted by hydroxyl anions 
      (OH(-)). These new single crystals were methodically characterized by powder and 
      single-crystal X-ray diffraction (SXRD), scanning electron microscopy (SEM), 
      Fourier transform-IR spectroscopy (FT-IR), and energy-dispersive X-ray 
      spectroscopy (EDS). We have discovered a previously unreported OH(-) inclusion 
      site substituting the Cl(-) anion during the ion-exchanging process. Finally, we 
      evaluated the atomic rearrangements of the other species involved in the 
      structure. These movements are associated with ionic exchange, which can be 
      justified from an energetic point of view. We also found a novel phase 
      transformation at high temperature. When the crystals are heated over 1753 K the 
      apatite system evolves to a less ordered monoclinic structure, in which the 
      complete loss of the species in the anionic channel (Cl(-), OH(-)) has been 
      confirmed.
FAU - Garcia-Tunon, Esther
AU  - Garcia-Tunon E
AD  - Instituto de Ceramica de Galicia, Universidad Santiago de Compostela, Santiago de 
      Compostela, Spain. esther.garcia-tunon@imperial.ac.uk
FAU - Dacuna, Bruno
AU  - Dacuna B
FAU - Zaragoza, Guillermo
AU  - Zaragoza G
FAU - Franco, Jaime
AU  - Franco J
FAU - Guitian, Francisco
AU  - Guitian F
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20120913
PL  - United States
TA  - Acta Crystallogr B
JT  - Acta crystallographica. Section B, Structural science
JID - 8403252
RN  - 0 (Anions)
RN  - 0 (Antiporters)
RN  - 0 (Apatites)
RN  - 0 (Chlorides)
RN  - 0 (Ions)
RN  - 0 (chloride-base exchanger)
RN  - 1306-04-3 (chlorapatite)
SB  - IM
MH  - Anions/*chemistry
MH  - Antiporters/*chemistry
MH  - Apatites/*chemical synthesis/*chemistry
MH  - Chlorides/*chemistry
MH  - Crystallography, X-Ray
MH  - Ions/*chemistry
MH  - X-Ray Diffraction
EDAT- 2012/09/21 06:00
MHDA- 2012/12/28 06:00
CRDT- 2012/09/21 06:00
PHST- 2011/09/26 00:00 [received]
PHST- 2012/05/01 00:00 [accepted]
PHST- 2012/09/21 06:00 [entrez]
PHST- 2012/09/21 06:00 [pubmed]
PHST- 2012/12/28 06:00 [medline]
AID - S0108768112019520 [pii]
AID - 10.1107/S0108768112019520 [doi]
PST - ppublish
SO  - Acta Crystallogr B. 2012 Oct;68(Pt 5):467-79. doi: 10.1107/S0108768112019520. 
      Epub 2012 Sep 13.