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Title: Neutron diffraction and X-ray absorption study of Ag{sub 5}Pb{sub 2}O{sub 6}

Abstract

Neutron diffraction and X-ray absorption measurements were carried out for a silver-lead oxide Ag{sub 5}Pb{sub 2}O{sub 6}. The powder neutron diffraction patterns could be fitted to the trigonal P3-bar 1m structure, as was found by X-ray diffraction. From the bond-valence-sum (BVS) analysis, the valences of the Ag and Pb ions were estimated to be about 1+ and 3.7+, respectively. The X-ray absorption measurements indicated that the ionic state of Ag is close to 1+, while that of Pb stands between 3+ and 4+. The deviation of the valence of the Pb ion from 4+ suggests a contribution of Pb orbitals to the metallic conduction as well as the possible superconductivity of this material, consistently with a recent band-structure calculation.

Authors:
 [1];  [2];  [2];  [2];  [3];  [4];  [4];  [4];  [4]
  1. Japan Atomic Energy Agency (JAEA), Mikazuki, Sayo-gun, Hyogo 679-5148 (Japan), E-mail: yoshiike@spring8.or.jp
  2. Japan Synchrotron Radiation Research Institute, Mikazuki, Sayo-gun, Hyogo 679-5198 (Japan)
  3. National Institute for Materials Science, Tsukuba, Ibaraki 304-0047 (Japan)
  4. Advanced Science Research Center, JAEA, Tokai, Ibaraki 319-1195 (Japan)
Publication Date:
OSTI Identifier:
21015660
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 1; Other Information: DOI: 10.1016/j.jssc.2006.10.025; PII: S0022-4596(06)00579-2; Copyright (c) 2006 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; ABSORPTION; ELECTRONIC STRUCTURE; LEAD OXIDES; NEUTRON DIFFRACTION; SILVER COMPOUNDS; SUPERCONDUCTIVITY; VALENCE; X RADIATION; X-RAY DIFFRACTION

Citation Formats

Yoshii, K., Mizumaki, M., Kato, K., Uruga, T., Abe, H., Nakamura, A., Shimojo, Y., Ishii, Y., and Morii, Y. Neutron diffraction and X-ray absorption study of Ag{sub 5}Pb{sub 2}O{sub 6}. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2006.10.025.
Yoshii, K., Mizumaki, M., Kato, K., Uruga, T., Abe, H., Nakamura, A., Shimojo, Y., Ishii, Y., & Morii, Y. Neutron diffraction and X-ray absorption study of Ag{sub 5}Pb{sub 2}O{sub 6}. United States. doi:10.1016/j.jssc.2006.10.025.
Yoshii, K., Mizumaki, M., Kato, K., Uruga, T., Abe, H., Nakamura, A., Shimojo, Y., Ishii, Y., and Morii, Y. Mon . "Neutron diffraction and X-ray absorption study of Ag{sub 5}Pb{sub 2}O{sub 6}". United States. doi:10.1016/j.jssc.2006.10.025.
@article{osti_21015660,
title = {Neutron diffraction and X-ray absorption study of Ag{sub 5}Pb{sub 2}O{sub 6}},
author = {Yoshii, K. and Mizumaki, M. and Kato, K. and Uruga, T. and Abe, H. and Nakamura, A. and Shimojo, Y. and Ishii, Y. and Morii, Y.},
abstractNote = {Neutron diffraction and X-ray absorption measurements were carried out for a silver-lead oxide Ag{sub 5}Pb{sub 2}O{sub 6}. The powder neutron diffraction patterns could be fitted to the trigonal P3-bar 1m structure, as was found by X-ray diffraction. From the bond-valence-sum (BVS) analysis, the valences of the Ag and Pb ions were estimated to be about 1+ and 3.7+, respectively. The X-ray absorption measurements indicated that the ionic state of Ag is close to 1+, while that of Pb stands between 3+ and 4+. The deviation of the valence of the Pb ion from 4+ suggests a contribution of Pb orbitals to the metallic conduction as well as the possible superconductivity of this material, consistently with a recent band-structure calculation.},
doi = {10.1016/j.jssc.2006.10.025},
journal = {Journal of Solid State Chemistry},
number = 1,
volume = 180,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • The molecular and crystal structures of two p-alkoxybenzylidene)-p'-toluidines C{sub 2}H{sub 5}O-C{sub 6}H{sub 4}-CH=N-C{sub 6}H{sub 4}-CH{sub 3} (1) and C{sub 4}H{sub 9}O-C{sub 6}H{sub 4}-CH=N-C{sub 6}H{sub 4}-CH{sub 3} (2) are determined by X-ray diffraction. Crystals 1 and 2 contain four and two crystallographically independent molecules, respectively. In 1, the geometry of the independent molecules is almost identical. In 2, the independent molecules differ in the conformation of the alkyl chain, which is disordered in one of them. An analysis of the crystal packing of 2 reveals the alternation of spacious layers formed by loosely packed aliphatic fragments of molecules and layers ofmore » closely packed aromatic fragments, which ensures the formation of the mesogenic phase in the course of melting of crystals 2. In crystal 1, loose aliphatic layers are absent.« less
  • By reacting Ag[sub 2]O and PbO[sub 2] with AgBiO[sub 3] and In[sub 2]O[sub 3], respectively, at temperatures between 770 and 820 K and oxygen pressures of 100 MPa for 4 days, mixed crystals according to the formula Ag[sub 5]Pb[sub 2[minus]x]M[sub x]O[sub 6] (M = Bi[sup 3+] and In[sup 3+]) in the stability range from x = 0 to x = 1 (In x[sub max] = 0.75) were formed. As characterized by X-ray power diffractometry the substitution of Bi[sup 3+] for Pb[sup 4+] leads to an increase of the cell volume from 196.4 (undoped sample) to 200.4 [Angstrom][sup 3] (x =more » 1), while In[sup 3+] decreases it to 189.9 [Angstrom][sup 3]. As their metallic behavior is lost, the resistivity of the Bi-doped compounds grows drastically with increasing Bi-content, while In-doping shows only a small increase in resistivity. 7 refs., 6 figs., 1 tab.« less
  • X-ray diffraction (XRD) and low-field microwave absorption (LFMA) have been measured for a series of Bi{sub 1.6}Ph{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} superconducting samples prepared at different sintering temperatures that display zero resistance between 50 and 98 K. Multiphase formation is observed in all samples. XRD results suggest that the fraction of the high-transition temperature ({Tc}) phase denoted as 2,223 grows with increasing sintering time and temperature compared to the low-{Tc} phase denoted as 2,212, although the 2,212 phase always predominates. Simultaneously, several impurity phases also increase. The 2,223 phase and 2,210 phase seem to be formed by the disproportionationmore » of the 2,212 phase. The incorporation of Pb in the lattice accelerates this disproportionation process. LFMA signals reveal the presence of two superconducting phases with {Tc} close to 75 and 115 K. The intensity of the microwave absorption due to the low {Tc} phase is 3-6 times higher than that of the high {Tc} phase. No electron spin resonance signal has been detected for this superconducting system above or below {Tc}, which indicates the lack of paramagnetic impurity phases.« less
  • The title compound, a new one, the preparation of which is described, has been investigated structurally by both X-ray diffraction at ca. 295 K and neutron diffraction at ca. 20 K. The space group is P1 and the unit cell has the following dimensions, where in each case the X-ray value is given first followed by the neutron value: a = 8.950 (1) A, 8.942 (8) A; b = 9.112 (1) A, 8.902 (8) A; c = 8.928 (2) A, 8.774 (8) A; ..cap alpha.. = 103.38 (1)/sup 0/, 103.4 (2)/sup 0/; ..beta.. = 93.75 (2)/sup 0/, 95.2 (1)/sup 0/;more » ..gamma.. = 70.19 (1)/sup 0/, 69.9 (2)/sup 0/; V = 666.4 (3) A/sup 3/, 638 (2) A/sup 3/. The structure was first solved and refined (211 variables) by using 2605 independent X-ray reflections with F/sup 2/ > 3sigma(F/sup 2/) to R = 0.046. Neutron data, 2137 reflections with F/sup 2/ > 2sigma(F/sup 2/), were then used to refine 261 variables including all hydrogen atoms anisotropically to R = 0.067. The structure consists of centrosymmetric (V(H/sub 2/O)/sup 6/)/sup 3 +/ and H/sub 5/O/sub 2//sup +/ cations and CF/sub 3/SO/sub 3//sup -/ anions. All hydrogen atoms participate in hydrogen bonds. The H/sub 5/O/sub 2//sup +/ ion appears to be truly centrosymmetric with an O...O distance of 2.430 (3) A at 20 K; the configuration at each oxygen atom is highly pyramidal. The (V(H/sub 2/O)/sub 6/)/sup 3 +/ cation has nearly flat water molecules (i.e., sums of bond angles about oxygen atoms are 357.7-359.7/sup 0/), and these are arranged to give the hexaaquo ion essentially D/sub 3d/ symmetry of the sort in which the six hydrogen atoms of three mutually cis water molecules are essentially coplanar. Possible reasons for the adoption of this particular highly symmetric arrangement are discussed. 16 references, 4 figures, 6 tables.« less