Production, Chemical Properties, Occurrence
Zirconia is produced by calcining zirconium compounds, exploiting its high thermal stability.
Unlike TiO2, which features octahedral Ti in all phases, zirconia consists of seven-coordinate zirconium centres. This difference is attributed to the larger size of Zr atom relative to the Ti atom.
Zirconia is relatively unreactive chemically. It is attacked by fluoride and alkalis. When heated with carbon, it converts to zirconium carbide. When heated with carbon in the presence of chlorine, it converts to zirconium tetrachloride. This conversion is the basis for the purification of zirconium metal and is analogous to the Kroll process.
Aside from baddeleyite, another naturally occurring form of ZrO2 is the very rare cubic mineral tazheranite (Zr,Ti,Ca)O2 (and a doubtful mineral arkelite).
Read more about this topic: Zirconium Dioxide
Famous quotes containing the words chemical and/or occurrence:
“Ants are so much like human beings as to be an embarrassment. They farm fungi, raise aphids as livestock, launch armies into war, use chemical sprays to alarm and confuse enemies, capture slaves, engage in child labor, exchange information ceaselessly. They do everything but watch television.”
—Lewis Thomas (b. 1913)
“One is absolutely sickened, not by the crimes that the wicked have committed, but by the punishments that the good have inflicted; and a community is infinitely more brutalised by the habitual employment of punishment than it is by the occasional occurrence of crime.”
—Oscar Wilde (18541900)