Melting points group 2 oxides

Platinum is classed by tradition and commercial usefulness as a precious metal that is soft, dense, dull, and silvery-white in color, and it is both malleable and ductile and can be formed into many shapes. Platinum is considered part of the precious metals group that includes gold, silver, iridium, and palladium. It is noncorrosive at room temperature and is not soluble in any acid except aqua regia. It does not oxidize in air, which is the reason that it is found in its elemental metallic form in nature. Its melting point is 1,772°C, its boiling point is 3,827°C, and its density is 195.09g/cm. ... 

Introduction of flexible spacer units such as methylene, methylene oxide, and dimethyl-siloxane groups lowers the melting point and increases the temperature range within which the mesophase is stable. Often these spacer units are introduced by copolymerization. Thus, preformed p-acetoxybenzoic acid is reacted with PET, introducing a mesogenic unit in a polymer that has flexible spacer units (from the ethylene glycol) in it. 

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