245 reported on the synthesis of linear but alsobranched polymers prepared by di-, tri-, and tetra-alkyne andazide monomers like the combination of tripropargylamine(B 3)and(dihydroxymethyl)(diazidomethyl)amine(A 2)(com-pare the general outline in Scheme 17).
When discussing mineral formations in caves, we often talk about stalactites and stalagmites. A stalactite is an icicle-shaped formation that hangs from the ceiling of a cave, and is produced by precipitation of minerals from water dripping through the cave ceiling. Most stalactites have pointed tips.
A meteorite is a fragment of rock or iron from outer space, usually a meteoroid or asteroid, which survives passage through the atmosphere as a meteor to impact the surface of the Earth. Meteorites are believed to originate in the asteroid belt between the planets of Mars and Jupiter. A meteorite may range in size from less than a gram to more than 60 tons. When the path of these space rocks intersects with Earth's orbit, the meteoroid enters the atmosphere at high velocity causing the luminous phenomena we call a meteor or shooting star.