The synthesis and characterization of Pb5S2I6 whiskers and tubules

Pb5S2I6 whiskers and tubules were synthesized from the reaction among lead chloride, thiourea, and excess sodium iodide under hydrothermal conditions at 200 °C for 20–40 h. XRD, SEM, XPS, ICP-AES, and TEM characterized the final products. Most products are whiskers with structure of 3–4 mm in length, 0.5–2.0 μm in diameter for a singular one. Meanwhile, about 10% tubules are produced in the process. The tubules are 3–6 mm in length, 8–20 μm in diameter, and 1–3 μm in thickness. Nanowhiskers were also produced in the route at 180–200 °C for 8–10 h. Raman spectra show that the Pb5S2I6 crystals have complex vibrational modes of PbS and PbI2.