Wide band gap material; exhibits both conduction and luminescence properties. Prepn: L. de Boisbaudran, Compt. Rend. 86, 941 (1878). Synthesis of nanostructures: S. Sharma, M. K. Sunkara, J. Am. Chem. Soc. 124, 12288 (2002); and photoluminescence properties of nanowires: X. C. Wu et al., Chem. Phys. Lett. 328, 5 (2000). Polymorphism study: R. Roy et al., J. Am. Chem. Soc. 74, 719 (1952). Crystal structure of β-form: S. Geller, J. Chem. Phys. 33, 676 (1960). Electrical properties: M. R. Lorenz et al., J. Phys. Chem. Solids 28, 403 (1967). Toxicity study: R. K. Wolff et al., J. Appl. Toxicol. 8, 191 (1988). Use as a dehydration catalyst: B. H. Davis et al., J. Org. Chem. 44, 2142 (1979).