Topochemical polymerization is the only polymerization technique whose product has this property. Hydrothermal synthesis uses an autoclave to make materials with this property. A sample can (-5[1])be purified and given this property by heating it in a narrow region moving upward from the bottom in zone melting. Materials with this property can be made by the Bridgman–Stockbarger and (*) Czokralski methods. Having this property distinguishes boules from other ingots. Most semiconductor manufacturing requires silicon wafers that have this property. Making solids with this property requires that cooling or evaporation be slow to reduce growth rate and may be aided by a small “seed” with this property. For 10 points, name this property in which a solid lacks grain boundaries so that the entire solid is one lattice. ■END■ (10[1])