skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The crystallographic and magnetic characteristics of Sr{sub 2}CrO{sub 4} (K{sub 2}NiF{sub 4}-type) and Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} (apatite-type)

Abstract

Solid-state reaction between SrCO{sub 3}, Cr{sub 2}O{sub 3} and SrF{sub 2} has produced the apatite phase Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} and Sr{sub 2}CrO{sub 4} which adopts the K{sub 2}NiF{sub 4}-type structure. The reaction outcome was very sensitive to the heating rate with rapid rise times favouring the formation of Sr{sub 2}CrO{sub 4}, which has been synthesised at ambient pressure for the first time. Powder X-ray diffraction and electron diffraction confirmed that Sr{sub 2}CrO{sub 4} adopts a body centred tetragonal cell (space group I4/mmm) with lattice parameters a=3.8357(1) A and c=12.7169(1) A, while a combination of neutron and X-ray diffraction verified Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} is hexagonal (space group P6{sub 3}/m) with lattice parameters a=9.9570(1) A and c=7.4292(1) A. X-ray photoelectron spectroscopy and magnetic measurements were used to characterise the oxidation states of chromium contained within these phases. - Graphical abstract: A solid-state reaction between SrCO{sub 3}, Cr{sub 2}O{sub 3} and SrF{sub 2} produced Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} apatite and Sr{sub 2}CrO{sub 4} which adopts the K{sub 2}NiF{sub 4}-type structure. Powder X-ray and electron diffraction confirmed that Sr{sub 2}CrO{sub 4} is body-centred tetragonal, while a combination of neutron and X-ray diffraction verified Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} ismore » hexagonal. X-ray photoelectron spectroscopy and magnetic measurements identified the oxidation states of chromium in these phases.« less

Authors:
 [1];  [2];  [2];  [3];  [2];  [2]
  1. Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore), E-mail: tbaikie@ntu.edu.sg
  2. Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore)
  3. Laboratoire CRISMAT, UMR CNRS 6508, ISMRA-ENSICAEN, 6 Boulevard du Marechal Juin, 14050, Caen, Cedex (France)
Publication Date:
OSTI Identifier:
21015806
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 5; Other Information: DOI: 10.1016/j.jssc.2007.02.023; PII: S0022-4596(07)00097-7; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; APATITES; CHROMATES; CHROMIUM OXIDES; CRYSTALLOGRAPHY; ELECTRON DIFFRACTION; HEXAGONAL LATTICES; LATTICE PARAMETERS; NEUTRON DIFFRACTION; SPACE GROUPS; STRONTIUM CARBONATES; STRONTIUM FLUORIDES; TETRAGONAL LATTICES; X RADIATION; X-RAY DIFFRACTION; X-RAY PHOTOELECTRON SPECTROSCOPY

Citation Formats

Baikie, Tom, Ahmad, Zahara, Srinivasan, Madhavi, Maignan, Antoine, Pramana, Stevin S., and White, T.J. The crystallographic and magnetic characteristics of Sr{sub 2}CrO{sub 4} (K{sub 2}NiF{sub 4}-type) and Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} (apatite-type). United States: N. p., 2007. Web. doi:10.1016/j.jssc.2007.02.023.
Baikie, Tom, Ahmad, Zahara, Srinivasan, Madhavi, Maignan, Antoine, Pramana, Stevin S., & White, T.J. The crystallographic and magnetic characteristics of Sr{sub 2}CrO{sub 4} (K{sub 2}NiF{sub 4}-type) and Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} (apatite-type). United States. doi:10.1016/j.jssc.2007.02.023.
Baikie, Tom, Ahmad, Zahara, Srinivasan, Madhavi, Maignan, Antoine, Pramana, Stevin S., and White, T.J. Tue . "The crystallographic and magnetic characteristics of Sr{sub 2}CrO{sub 4} (K{sub 2}NiF{sub 4}-type) and Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} (apatite-type)". United States. doi:10.1016/j.jssc.2007.02.023.
@article{osti_21015806,
title = {The crystallographic and magnetic characteristics of Sr{sub 2}CrO{sub 4} (K{sub 2}NiF{sub 4}-type) and Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} (apatite-type)},
author = {Baikie, Tom and Ahmad, Zahara and Srinivasan, Madhavi and Maignan, Antoine and Pramana, Stevin S. and White, T.J.},
abstractNote = {Solid-state reaction between SrCO{sub 3}, Cr{sub 2}O{sub 3} and SrF{sub 2} has produced the apatite phase Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} and Sr{sub 2}CrO{sub 4} which adopts the K{sub 2}NiF{sub 4}-type structure. The reaction outcome was very sensitive to the heating rate with rapid rise times favouring the formation of Sr{sub 2}CrO{sub 4}, which has been synthesised at ambient pressure for the first time. Powder X-ray diffraction and electron diffraction confirmed that Sr{sub 2}CrO{sub 4} adopts a body centred tetragonal cell (space group I4/mmm) with lattice parameters a=3.8357(1) A and c=12.7169(1) A, while a combination of neutron and X-ray diffraction verified Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} is hexagonal (space group P6{sub 3}/m) with lattice parameters a=9.9570(1) A and c=7.4292(1) A. X-ray photoelectron spectroscopy and magnetic measurements were used to characterise the oxidation states of chromium contained within these phases. - Graphical abstract: A solid-state reaction between SrCO{sub 3}, Cr{sub 2}O{sub 3} and SrF{sub 2} produced Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} apatite and Sr{sub 2}CrO{sub 4} which adopts the K{sub 2}NiF{sub 4}-type structure. Powder X-ray and electron diffraction confirmed that Sr{sub 2}CrO{sub 4} is body-centred tetragonal, while a combination of neutron and X-ray diffraction verified Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} is hexagonal. X-ray photoelectron spectroscopy and magnetic measurements identified the oxidation states of chromium in these phases.},
doi = {10.1016/j.jssc.2007.02.023},
journal = {Journal of Solid State Chemistry},
number = 5,
volume = 180,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • The reaction of Re{sub 2}O{sub 7} with XeF{sub 6} in anhydrous HF provides a convenient route to high-purity ReO{sub 2}F{sub 3}. The fluoride acceptor and Lewis base properties of ReO{sub 2}F{sub 3} have been investigated leading to the formation of [M][ReO{sub 2}F{sub 4}] [M = Li, Na, Cs, N(CH{sub 3}){sub 4}], [K][Re{sub 2}O{sub 4}F{sub 7}], [K][Re{sub 2}O{sub 4}F{sub 7}]{center_dot}2ReO{sub 2}F{sub 3}, [Cs][Re{sub 3}O{sub 6}F{sub 10}], and ReO{sub 2}F{sub 3}(CH{sub 3}CN). The ReO{sub 2}F{sub 4}{sup {minus}}, Re{sub 2}O{sub 4}F{sub 7}{sup {minus}}, and Re{sub 3}O{sub 6}F{sub 10{sup {minus}} anions and the ReO{sub 2}F{sub 3}(CH{sub 3}CN) adduct have been characterized in the solidmore » state by Raman spectroscopy, and the structures [Li][ReO{sub 2}F{sub 4}], [K][Re{sub 2}O{sub 4}F{sub 7}], [K][Re{sub 2}O{sub 4}F{sub 7}]{center_dot}2ReO{sub 2}F{approximately}3}, [Cs][Re{sub 3}O{sub 6}F{sub 10}], and ReO{sub 3}F(CH{sub 3}CN){sub 2}{center_dot}CH{sub 3}CN have been determined by X-ray crystallography. The structure of ReO{sub 2}F{sub 4}{sup {minus}} consists of a cis-dioxo arrangement of Re-O double bonds in which the Re-F bonds trans to the oxygen atoms are significantly lengthened as a result of the trans influence of the oxygens. The Re{sub 2}O{sub 4}F{sub 7}{sup {minus}} and Re{sub 3}O{sub 6}F{sub 10}{sup {minus}} anions and polymeric ReO{sub 2}F{sub 3} are open chains containing fluorine-bridged ReO{sub 2}F{sub 4} units in which each pair of Re-O bonds are cis to each other and the fluorine bridges are trans to oxygens. The trans influence of the oxygens is manifested by elongated terminal Re-F bonds trans to Re-O bonds as in ReO{sub 2}F{sub 4}{sup {minus}} and by the occurrence of both fluorine bridges trans to Re-O bonds. Fluorine-19 NMR spectra show that ReO{sub 2}F{sub 4}{sup {minus}}, Re{sub 2}O{sub 4}F{sub 7}{sup {minus}}, and ReO{sub 2}F{sub 3}(CH{sub 3}CN) have cis-dioxo arrangements in CH{sub 3}CN solution. Density functional theory calculations at the local and nonlocal levels confirm that the cis-dioxo isomers of ReO{sub 2}F{sub 4}{sup {minus}} and ReO{sub 2}F{sub 3}(CH{sub 3}CN), where CH{sub 3}CN is bonded trans to an oxygen, are the energy-minimized structures. The adduct ReO{sub 3}F(CH{sub 3}CN){sub 2}{center_dot}CH{sub 3}CN was obtained by hydrolysis of ReO{sub 2}F{sub 3}(CH{sub 3}CN), and was shown by X-ray crystallography to have a facial arrangement of oxygen atoms on rhenium.« less
  • K{sub 3}InF{sub 6} is synthesized by a sol-gel route starting from indium and potassium acetates dissolved in isopropanol in the stoichiometry 1:3, with trifluoroacetic acid as fluorinating agent. The crystal structures of the organic precursors were solved by X-ray diffraction methods on single crystals. Three organic compounds were isolated and identified: K{sub 2}InC{sub 10}O{sub 10}H{sub 6}F{sub 9}, K{sub 3}InC{sub 12}O{sub 14}H{sub 4}F{sub 18} and K{sub 3}InC{sub 12}O{sub 12}F{sub 18}. The first one, deficient in potassium in comparison with the initial stoichiometry, is unstable. In its crystal structure, acetate as well as trifluoroacetate anions are coordinated to the indium atom. Themore » two other precursors are obtained, respectively, by quick and slow evaporation of the solution. They correspond to the final organic compounds, which give K{sub 3}InF{sub 6} by decomposition at high temperature. The crystal structure of K{sub 3}InC{sub 12}O{sub 14}H{sub 4}F{sub 18} is characterized by complex anions [In(CF{sub 3}COO){sub 4}(OH{sub x}){sub 2}]{sup (5-2x)-} and isolated [CF{sub 3}COOH{sub 2-x}]{sup (x-1)-} molecules with x=2 or 1, surrounded by K{sup +} cations. The crystal structure of K{sub 3}InC{sub 12}O{sub 12}F{sub 18} is only constituted by complex anions [In(CF{sub 3}COO){sub 6}]{sup 3-} and K{sup +} cations. For all these compounds, potassium cations ensure only the electroneutrality of the structure. IR spectra of K{sub 2}InC{sub 10}O{sub 10}H{sub 6}F{sub 9} and K{sub 3}InC{sub 12}O{sub 12}F{sub 18} were also performed at room temperature on pulverized crystals.« less
  • Two new K/sub 2/NiF/sub 4/-type oxides Sr/sub 0.50/La/sub 1.50/Ni/sub 0.50/Mg/sub 0.50/O/sub 4/ and Sr/sub 1.50/La/sub 0.50/Ti/sub 0.50/Ni/sub 0.50/O/sub 4/ have been prepared. X-ray diffraction, magnetic measurements, and EPR investigations characterize a low-spin configuration in the octahedral sites of low spin Ni(III) (t/sub 2g//sup 6/e/sub g//sup 1/). The nature of the distortion has been determined by comparing the g/parallel/ and g/perpendicular/ values at room temperature. While a strong elongation of the NiO/sub 6/ octahedra has been observed for La/sub 2/Li/sub 0.50/Ni/sub 0.50/O/sub 4/, quasi-regular octahedra can be expected for Sr/sub 0.50/La/sub 1.50/Mg/sub 0.50/O/sub 4/ g/parallel/ /approx equal/ g/perpendicular/ and compressed onesmore » seem to occur in Sr/sub 1.50/La/sub 0.50/Ti/sub 0.50/Ni/sub 0.50/O/sub 4/ g/parallel/ > g/perpedicular/. An explanation of this structural evolution is proposed based on bond competition considerations.« less
  • Trace amounts of H/sub 2/O and limited exposure to air of reaction mixtures of UCl/sub 4/ and 12-crown-4, 15-crown-5, benzo-15-crown-5, 18-crown-6, or dibenzo-18-crown-6 in 1:3 mixtures of CH/sub 3/OH and CH/sub 3/CN resulted in the hydrolysis and oxidation of UCl/sub 4/ to (UO/sub 2/Cl/sub 4/)/sup 2/minus//. In the presence of these crown ethers, it has been possible to isolate intermediate products via crystallization of crown complexes of the (UO/sub 2/Cl/sub 4/)/sup 2/minus// ion, the (UCl/sub 6/)/sup 2/minus// ion, and (UO/sub 2/Cl/sub 2/(OH/sub 2/)/sub 3/). The neutral moiety crystallizes as a hydrogen-bonded crown ether complex; however, crown ether complexation of amore » counterion, either an ammonium ion formed during the oxidation of U(IV) or a Na/sup +/ ion leached from glass reaction vessels, resulted in novel crystalline complexes of the ionic species. ((NH/sub 4/)(15-crown-5)/sub 2/)/sub 2/(UO/sub 2/Cl/sub 4/) /times/ 2CH/sub 3/CN, ((NH/sub 4/)(benzo-15-crown-5)/sub 2/)/sub 2/(UCl/sub 6/) /times/ 4CH/sub 3/CN, and ((NH/sub 4/)(dibenzo-18-crown-6))/sub 2/(UO/sub 2/Cl/sub 4/) /times/ 2CH/sub 3/CN have been structurally characterized by single-crystal X-ray diffraction techniques. The results of all the crystal studies are presented in detail. The ammonium ions interact with the crown ethers via hydrogen-bonding and electrostatic interactions. 15-Crown-5 and benzo-15-crown-5 form 2:1 sandwich cations, allowing no H/sub 4/N/sup +//hor ellipsis/(UO/sub 2/Cl/sub 4/)/sup 2/minus// interaction. The dibenzo-18-crown-6 complexed ammonium ions are 1:1 and form bifurcated hydrogen bonds with the chlorine atoms in the (UO/sub 2/Cl/sub 4/)/sup /minus// anion. The formation of (Na(12-crown-4)/sub 2//sub 2/(UO/sub 2/Cl/sub 4/) /times/ 2OHMe and (UO/sub 2/Cl/sub 2/(OH)/sub 2/)/sub 3/) /times/ 18-crown-6 /times/ H/sub 2/O /times/ OHMe has been confirmed by preliminary single-crystal X-ray diffraction studies.« less
  • Single crystals of the strontium phosphate orthoborate metaborate, Sr{sub 10}[(PO{sub 4}){sub 5.5}(BO{sub 4}){sub 0.5}](BO{sub 2}), were grown from the melt and investigated by X-ray diffraction (space group P3-bar, No. 147; a=9.7973(8) A, c=7.3056(8) A, V=607.29(10) A{sup 3}, Z=1). The crystal structure is closely related to apatite and contains linear metaborate groups, [BO{sub 2}]{sup -} (point group D{sub i}nfinity{sub h}, B-O=1.284(11) A) taking positions within the channels running along the three-fold inversion axis. Strontium sites are found to be fully occupied while [PO{sub 4}]{sup 3-} tetrahedra are partially replaced by [BO{sub 4}]{sup 5-} groups. - Graphical abstract: Single crystals of themore » strontium phosphate orthoborate metaborate, Sr{sub 10}[(PO{sub 4}){sub 5.5}(BO{sub 4}){sub 0.5}](BO{sub 2}), were grown from the melt and structurally characterized. The crystal structure is closely related to apatite and contains uncommon linear [BO{sub 2}]{sup -} metaborate groups taking positions within the channels running along the three-fold inversion axis.« less