NDLI: Preferential occupancy of strontium in the hydroxyapatite lattice in biphasic mixtures formed from non-stoichiometric calcium apatites

Content Provider	World Health Organization (WHO)-Global Index Medicus
Author	Mishra, Sandeep K. Kannan, S. Udhay Kiran, R. Nandha Kumar, P.
Description	Author Affiliation: Nandha Kumar P ( Centre for Nanoscience and Technology, Pondicherry University, Puducherry-605 014, India. para_kanna@yahoo.com.)
Abstract	The present study reports the variations in phase content of biphasic mixtures and structural changes induced by different levels of strontium addition in calcium-deficient apatite (Ca/P = 1.60) powders during heat treatment. The synthesis was attempted by an in situ aqueous precipitation technique and X-ray diffraction, Raman spectroscopy and Rietveld refinement of the powder X-ray diffraction data were employed for comprehensive analysis. The results confirm the preferential occupancy of $Sr^{2+}$ at two different $Ca^{2+}$ sites of the hydroxyapatite $[Ca_{10}(PO_{4})_{6}(OH)_{2},$ HAP] lattice, with the $Ca^{2+}$ (2) site accommodating more $Sr^{2+}$ than the $Ca^{2+}$ (1) site. Increasing $Sr^{2+}$ addition in calcium-deficient apatite has led to a decline in the phase content of β-tricalcium phosphate $[β-Ca_{3}(PO_{4})_{2},$ β-TCP] in biphasic mixtures of HAP and β-TCP. $Sr^{2+}$ addition exceeding the critical limit of a (Ca + Sr)/P > 1.75 molar ratio has resulted in the formation of CaO as an additional phase, and this justifies the lack of enough $PO_{4}^{3−}$ ions to promote any kind of calcium phosphate precipitation. $Sr^{2+}$ accommodation in the lattice sites of HAP has induced an increase in the lattice parameters and has also led to the significant distortion of the $PO_{4}$ tetrahedron and OH groups, confirmed by Raman and FT-IR spectroscopic techniques.
ISSN	14779226
Issue Number	17
Journal	Dalton Trans.
Volume Number	44
e-ISSN	13645447
Language	English
Publisher	Royal Society of Chemistry
Publisher Date	2015-05-07
Publisher Place	Great Britain (UK)
Access Restriction	Subscribed
Subject Keyword	Chemistry
Content Type	Text
Resource Type	Article
Subject	Inorganic Chemistry

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in