Structure
Paratellurite, α-TeO2, converts at high pressure into the β-, tellurite form. Both the α-, (paratellurite) and β- (tellurite forms) contain four coordinate Te with the oxygen atoms at four of the corners of a trigonal bipyramid. In paratellurite all vertices are shared to give a rutile-like structure, where the O-Te-O bond angle are 140°. α-TeO2 In tellurite pairs of trigonal pyramidal, TeO4 units, sharing an edge, share vertices to then form a layer. The shortest Te-Te distance in tellurite is 317 pm, compared to 374 pm in paratellurite. Similar Te2O6 units are found in the mineral denningite.
TeO2 melts at 732.6 °C, forming a red liquid.
Read more about this topic: Tellurium Dioxide
Famous quotes containing the word structure:
“In the extent and proper structure of the Union, therefore, we behold a republican remedy for the diseases most incident to republican government.”
—James Madison (17511836)
“Each structure and institution here was so primitive that you could at once refer it to its source; but our buildings commonly suggest neither their origin nor their purpose.”
—Henry David Thoreau (18171862)
“The question is still asked of women: How do you propose to answer the need for child care? That is an obvious attempt to structure conflict in the old terms. The questions are rather: If we as a human community want children, how does the total society propose to provide for them?”
—Jean Baker Miller (20th century)