tetrahedra

Lowell Gilbert @ 13, kid bitzer @ 15 -- Remember that the tetrahedral shape is that of the four bonds of the carbon atom; the implied tetrahedra are connected tip-to-tip, not solidly packed.

Making Light: The tastemakers of tomorrow 2010

Each of the 3 corners “shares” an oxygen atom with other tetrahedra, giving a ratio in the formula of 1 Si to 2.5 O, or Si2O5.

Open thread: questions and explanations - The Panda's Thumb 2009

In sheet silicates, each silicate tetrahedron is joined at 3 corners to other tetrahedra in sheet form.

Open thread: questions and explanations - The Panda's Thumb 2009

Five points form the vertices of two regular tetrahedra, joined on a common face situated in the horizontal plane.

Wolfram Blog : Equations or Exploding Teapots? 2007

“Clay” as a mineral refers to a “cousin” of micas; that is, a silicate mineral containing structural sheets of silica tetrahedra tetrahedral arrangements of one Si and 4 Oxygen atoms, with the Oxygen atoms at the 4 corners.

Open thread: questions and explanations - The Panda's Thumb 2009

In the case of chrysotile, an octahedral brucite layer having the formula (Mg6O4 (OH) 4) -4 is intercalated between each silicate tetrahedra sheet.

Geology of asbestos 2007

As with all silicate minerals, the basic building blocks of asbestos fibers are the silicate tetrahedra which may occur as double chains (Si4O11) -6, as in the amphiboles, or in sheets (Si4O10) -4, as in chrysotile.

Geology of asbestos 2007

The crystalline structure common to amphibole minerals consists of two ribbons of silicate tetrahedra placed back to back.

Geology of asbestos 2007

Between craters the basalt was strewn in small tetrahedra, with angles rubbed and rounded, stone tight to stone like tesseract upon

Seven Pillars of Wisdom Thomas Edward 2003

There were even stranger shapes, exploiting almost every possibility of geometry - bizarre, translucent kites, tetrahedra, spheres, polyhedra, tangles of twisted ribbons ...

2061 Odyssey Three Clarke, Arthur C. 1987