| The first part of this dissertation discusses the use of hydrothermal reactions and vapor phase transport methods to synthesize antimony oxysulfide (Sb{dollar}sb2{dollar}OS{dollar}sb2{dollar} or Sb{dollar}sb2{dollar}O{dollar}sb2{dollar}S), and the use of radio frequency sputtering techniques to synthesize molybdenum oxysulfide. Although oxysulfides could not be prepared, two new phases were identified in the products from the hydrothermal reactions: a new form of antimony sulfide, space group Pnma, a = 53.49(9)A, b = 3.853(2)A, and c = 11.015(7)A, and KSb{dollar}sb5{dollar}S{dollar}sb8{dollar}, space group Pn, a = 8.1A, b = 19.6A, c = 9.0A, and {dollar}beta{dollar} = 92{dollar}spcirc{dollar}.; In the second part of this work the effect of the substitution of various metallic elements for each cation in the superconducting compound YBa{dollar}sb2{dollar}Cu{dollar}sb3{dollar}O{dollar}sb{lcub}6+delta{rcub}{dollar} was studied with the expectation that clues might be obtained that will shed light on the mechanism responsible for high-T{dollar}sb{lcub}rm c{rcub}{dollar} superconductivity. Published research results show that the transition temperature is essentially independent of the mass of the constituents, implying that the phonon mechanism plays a minor role in high-T{dollar}sb{lcub}rm c{rcub}{dollar} superconductivity. The results obtained in this research show that the substitution of Pr{dollar}sp{lcub}4+{rcub}{dollar} for Y{dollar}sp{lcub}3+{rcub}{dollar}, Nd{dollar}sp{lcub}3+{rcub}{dollar} for Ba{dollar}sp{lcub}2+{rcub}{dollar}, cobalt and iron for copper all caused a change in the electrical conductivity of the normal state from metallic to semiconducting behavior and a monotonic decrease in T{dollar}sb{lcub}rm c{rcub}{dollar}. This is interpreted to mean that an electronic mechanism is probably responsible for the high-T{dollar}sb{lcub}rm c{rcub}{dollar} superconducting effect.; The final part of this work concentrated on the phase diagram study of the Bi-Sr-Ca-Cu-O system between 800{dollar}spcirc{dollar}C to 880{dollar}spcirc{dollar}C because the new high-T{dollar}sb{lcub}rm c{rcub}{dollar} compounds occur here. The results of this study showed that the best phase-pure material exhibiting T{dollar}sb{lcub}rm c{rcub}{dollar} = 80 K was obtained from an initial mixture of 4Bi:3Sr:3Ca:4Cu. This phase has the stoichiometry Bi{dollar}sb2{dollar}Sr{dollar}sb2{dollar}CaCu{dollar}sb2{dollar}O{dollar}sb8{dollar} as published in the literature. The second phase was obtained from an initial mixture of 1Bi:1Sr:1Cu. The powder diffraction pattern and single-crystal X-ray photographs agree with the lattice constants reported for Bi{dollar}sb2{dollar}Sr{dollar}sb2{dollar}CuO{dollar}sb6{dollar}, T{dollar}sb{lcub}rm c{rcub}{dollar} = 7 K. A third phase was identified with a tentative stoichiometry Bi{dollar}sb2{dollar}Sr{dollar}sb4{dollar}Cu{dollar}sb2{dollar}O{dollar}sb9{dollar}, possible space groups F222, Fmm2, and Fmmm, a = 5.348(2)A, b = 23.969(5)A, and c = 33.929(8)A. A fourth phase, as judged from X-ray powder diffraction patterns, appears to be close to the composition Bi{dollar}sb4{dollar}Sr{dollar}sb5{dollar}Cu{dollar}sb5{dollar}O{dollar}sb{lcub}16{rcub}{dollar}. |
