Solid Sulfur Allotropes

Reductive transformation of iron and sulfur in schwertmannite-rich accumulations associated with acidified coastal lowlands

“…(7) and (8) is poorly understood. Of the elements, S 0 ðsÞ exhibits the largest number of solid-phase allotropes, with most consisting of unbranched cyclic molecules with ring sizes ranging from 6 to 20 atoms (Steudel and Eckert, 2004). Polymeric S 0 ðsÞ allotropes, comprising chains in a random coil or helical conformation, are also known to occur (Steudel and Eckert, 2004).…”

X-Ray Absorption Spectroscopy as a Probe of Microbial Sulfur Biochemistry: the Nature of Bacterial Sulfur Globules Revisited

“…Elemental ␣-sulfur was recrystallized at room temperature from xylene solutions of elemental sulfur. We note that while this is expected to yield predominantly ␣-sulfur containing predominantly S 8 (13), small quantities of other rings, such as S 7 , might contaminate the sample (35). Polymeric sulfur was prepared by quenching boiling sulfur in ice water.…”

The Reaction Mechanisms of H2S Decomposition into Hydrogen and Sulfur: Application of Classical and Biological Thermodynamics

“…Electron diffraction on the separate sulfur globule indicates a hexagonal structure of the sulfur crystallites with the interplanar spacing of 0.45, 0.29, and 0.15 nm. More than 30 allotropic modifications of solid sulfur are currently known [25,26] with changes in color from red to black, but no white hexagonal sulfur was found in the database. The only single absorption band at 880 cm -1 was observed in the Raman spectra of saturated water solution over precipitate of white globules, while the globules themselves are irreversible transferred into the solid S 8 under the laser beam of a Raman spectrometer.…”

“…They are growing in aqueous media from acid to alkaline pH values, at temperature ranging from +4 to +95°C, in both aerobic and completely anaerobic conditions [30,[32][33][34]. Many of the properties of "biological sulfur" S 0 produced with sulfur bacteria do not match the properties of any known chemical allotrope of elemental sulfur [25,26]. S 0 forms transparent droplets in diameter of up to 1 µm which are deposited inside or outside of the bacteria cells.…”