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Partial exchange of the Li{sup +}, Na{sup +} and K{sup +} alkaline cations in the HNi(PO{sub 4}).H{sub 2}O layered compound

Journal Article · · Journal of Solid State Chemistry
 [1];  [1];  [2];  [2];  [2];  [1]
  1. Dpto de Quimica Inorganica, Facultad de Ciencia y Tecnologia, Apdo. 644, E-48080 Bilbao (Spain)
  2. Dpto. de Mineralogia y Petrologia, Facultad de Ciencia y Tecnologia, Apdo. 644, E-48080 Bilbao (Spain)
The exchange of the Li{sup +}(1), Na{sup +}(2) and K{sup +}(3) alkaline cations in the layered HNi(PO{sub 4}).H{sub 2}O was carried out starting from a methanolic solution containing the Li(OH).H{sub 2}O hydroxide for (1) and the M(OH) (M=Na and K) hydroxides together with the (C{sub 6}H{sub 13}NH{sub 2}){sub 0.75}HNiPO{sub 4}.H{sub 2}O phases for (2) and (3). The compounds are stable until, approximately, 280{sup o}C for (1) and 400 deg. C for phases (2) and (3), respectively. The IR spectra show the bands belonging to the water molecule and the (PO{sub 4}){sup 3-} oxoanion. The diffuse reflectance spectra indicate the existence of Ni(II), d{sup 8}, cations in slightly distorted octahedral geometry. The calculated Dq and Racah (B and C) parameters have a mean value of Dq=765, B=905 and C=3895cm{sup -1}, respectively, in accordance with the values obtained habitually for this octahedral Ni(II) cation. The study of the exchange process performed by X-ray powder diffraction indicates that the exchange of the Li{sup +} cation in the lamellar HNi(PO{sub 4}).H{sub 2}O phase is the minor rapid reaction, whereas the exchange of the Na{sup +} and K{sup +} cations needs the presence of the intermediate (C{sub 6}H{sub 13}NH{sub 2}){sub 0.75}HNiPO{sub 4}.H{sub 2}O intercalate in order to obtain the required producth the sodium and potassium ions. The Scanning electronic microscopy (SEM) images show a mean size of particle of 5{mu}m. The Li{sup +} exchanged compound exhibits small ionic conductivity ({omega}cm{sup -1} is in the 10{sup -8}-10{sup -9} range) probably restrained by the methanol solvent. Magnetic measurements carried out from 5K to room temperature indicate antiferromagnetic coupling as the major interaction in the three phases. Notwithstanding the Li and K phases show a weak ferromagnetism at low temperatures.
OSTI ID:
20900918
Journal Information:
Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 12 Vol. 179; ISSN 0022-4596; ISSN JSSCBI
Country of Publication:
United States
Language:
English