Pressure-Induced Phase of Sulfur-Selenium

Science  06 Jan 1967:
Vol. 155, Issue 3758, pp. 79-80
DOI: 10.1126/science.155.3758.79


Crystals of a fibrous phase of sulfur-selenium obtained at 20 kilobars and 280°C are trigonal, the most probable space groups being P31 and P32, with a = 7.85, c = 4.62 ± 0.01 Å. The unit cell contains nine atoms, and the measured density of 3.20 g/cm3 implies five sulfur and four Se atoms. The structure contains mixed atom helices of 1.54 Å pitch and 0.91 Å average radius.