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Top Curr Chem (2003) 230:81–116 DOI 10.1007/b12111 Liquid Sulfur Ralf Steudel Institut für Chemie, Sekr. C2, Technische Universität Berlin, 10623 Berlin, Germany E-mail: steudel@schwefel.chem.tu-berlin.de Abstract The molecular composition as well as the physical properties (including spectra) of liquid sulfur are reviewed starting with a historic Introduction to explain the terms p-sulfur and m-sulfur. At all temperatures the melt contains homocyclic rings of between 6 and at least 35 atoms with S8 as the majority species as well as polymeric sulfur (S1) which becomes a major component only above 170 C. The polymer probably consists of very large rings at temperatures below 157 C but above this temperature very long diradicalic chains occur in addition. At temperatures above 300 C highly colored small molecules like S3 and, at even higher temperatures, S4 can be detected spectroscopically. According to quantum-chemical calculations branched rings (clusters) will be minor components at tem- peratures near the boiling point only. The temperature dependence of the composition is explained and the various polymerization theories for the transformation of S8 into S1 as well as the molecular nature of the polymer are discussed. In addition, the various analyti- cal techniques applied to solve the composition problem of liquid sulfur are described. Keywords Sulfur rings · Sulfur chains · Branched rings · Thermodynamics · Polymerization · Photochemistry 1 Introduction................................... 82 2 HistoricalReview[18]............................. 84 2.1 p-Sulfur...................................... 84 2.1.1 PreparationandPropertiesofp-Sulfur. . . . . . . . . . . . . . . . . . 84 2.1.2 MolecularMassofp-Sulfur.......................... 85 2.1.3 Concentrationofp-SulfurinSulfurMelts . . . . . . . . . . . . . . . . 85 2.1.4 RatesofFormationandDecayofp-Sulfur. . . . . . . . . . . . . . . . 86 2.1.5 EnthalpyofFormationofp-Sulfur..................... 86 2.1.6 MolecularNatureofp-Sulfur ........................ 87 2.2 PolymericSulfur(m-SulfurandS1).................... 87 2.2.1 Preparation of Polymeric Sulfur and its Concentration in Sulfur Melts 87 2.2.2 Propertiesofm-Sulfur............................. 89 2.2.3 RateofFormationofPolymericSulfur.................. 90 2.2.4 MolecularNatureofPolymericSulfur................... 90 2.3 DopingofSulfurMelts............................. 92 3 RecentResults.................................. 94 3.1 Analysis of Liquid Sulfur by Vibrational Spectroscopy . . . . . . . . 94 3.1.1 RamanSpectraofLiquidSulfur....................... 95 3.1.2 RamanSpectraofQuenchedSulfurMelts . . . . . . . . . . . . . . . . 96 Springer-Verlag Berlin Heidelberg 2003PDF Image | Topics in Current Chemistry
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