Ionic Conductivity, Structural, IR and Raman Spectroscopic Data of Olivine, Sr₂PbO₄, and Na₂CuF₄ Type Lithium and Sodium Chlorides Li₂ZnCl₄ and Na₂MCl₄ (M = Mg, Ti, Cr, Mn, Co, Zn, Cd)

Abstract

<jats:p>The ionic conductivities (complex impedance measurements) of the olivine type Li<jats:sub>2</jats:sub>ZnCl<jats:sub>4</jats:sub>, Na<jats:sub>2</jats:sub>ZnCl<jats:sub>4</jats:sub> and Na<jats:sub>2</jats:sub>CoCl<jats:sub>4</jats:sub>, the Sr<jats:sub>2</jats:sub>PbO<jats:sub>4</jats:sub> type Na<jats:sub>2</jats:sub>MgCl<jats:sub>4</jats:sub>, Na<jats:sub>2</jats:sub>MnCl<jats:sub>4</jats:sub>, and Na<jats:sub>2</jats:sub>CdCl<jats:sub>4</jats:sub>, and the novel Na<jats:sub>2</jats:sub>CrCl<jats:sub>4</jats:sub> with monoclinically distorted Sr<jats:sub>2</jats:sub>PbO<jats:sub>4</jats:sub> structure (Na<jats:sub>2</jats:sub>CuF<jats:sub>4</jats:sub> type) are presented. The specific conductivities of Li2ZnCl4 and the Na2MCl4 are about three orders of magnitude lower than those of the fast ionic conducting lithium chloride spinels Li[LiM ]Cl<jats:sub>4</jats:sub> (M = Mg, Mn. Fe. Cd. etc.) indicating that in the latter compounds the tetrahedrally coordinated lithium ions exhibit higher mobility than those on octahedral sites. The X-ray data including those of Sr<jats:sub>2</jats:sub>PbO<jats:sub>4</jats:sub> type Na<jats:sub>2</jats:sub>TiCl<jats:sub>4</jats:sub> and both the IR and Raman spectra (together with a group theoretical treatment) are also given. The spectra obtained confirm the different structure types of the ternary chlorides.</jats:p>

Comments on the Paper: “Synthesis, Growth and Optical, Mechanical, Electrical and Surface Properties of an Inorganic New Nonlinear Optical Crystal: Sodium Cadmium Tetra Chloride (SCTC)”

“…[ 7 ] reported on the Rietveld refined structures of the double chlorides, Na 2 MCl 4 (M = Mg, Cr, Cd), all of which adopt the Sr 2 PbO 4 ‐type structure and crystallize in the centrosymmetric orthorhombic space group Pbam ( Table 1 ). The unit cell (without esd) reported in the title paper appears to be in close agreement with the unit cell data reported in [6,7]. However, the noncentrosymmetric space group Pba 2 is inappropriate for Na 2 CdCl 4 .…”

“…and gave the formula of the SCTC crystal as Na 2 CdCl 4 in the experimental procedure, the correct literature citation could be identified as the 1987 paper by Lutz et al. [ 6 ] A later paper by Kanno et al. [ 7 ] reported on the Rietveld refined structures of the double chlorides, Na 2 MCl 4 (M = Mg, Cr, Cd), all of which adopt the Sr 2 PbO 4 ‐type structure and crystallize in the centrosymmetric orthorhombic space group Pbam ( Table 1 ).…”

“…However, the noncentrosymmetric space group Pba 2 is inappropriate for Na 2 CdCl 4 . Although no reason is given by the authors for choosing a space group different from Lutz et al., [ 6 ] the absence of refinement results renders the space group assignment unacceptable. The authors did not consider that the paper by Lutz et al.…”

“…In addition to the synthesis, the vibrational spectra, ionic conductivity, and the unit cell parameters were reported in ref. [6]. Lutz et al.…”

Synthesis, characterization and catalytic properties of tetrachlorocuprate(II) immobilized on layered double hydroxide

“…A broad band at 3000–3600 cm −1 in both spectra is characteristic of O─H stretching of hydroxide basal layer and interlayer water. The main bands related to intercalated and adsorbed anions and the metal–oxygen ν(M─O─M) stretching modes are, respectively, observed at 1000–1800 and 400–1000 cm −1 . The positions of all bands in the spectrum of LDH‐CuCl 4 2− are almost coincident with those in the spectrum of pure LDH, due to the fact that most bands of CuCl 4 2− almost coincide with the bands of LDH.…”