Barium titanate Barium titanate Barium titanate is an inorganic compound with chemical formula BaTiO. Barium titanate appears white as a powder and is transparent when prepared as large crystals. It is a ferroelectric ceramic material that exhibits the photorefractive effect and piezoelectric properties. It is used in capacitors, electromechanical transducers and nonlinear optics. The solid exists in one of five polymorphs depending on temperature. From high to low temperature, these crystal symmetries of the five polymorphs are hexagonal, cubic, tetragonal, orthorhombic, and rhombohedral crystal structure. All of these phases exhibit the ferroelectric effect apart from the cubic phase. The high temperature cubic
Pewter Pewter Pewter () is a malleable metal alloy. It is traditionally composed of 85–99% tin, mixed with copper, antimony, bismuth, and sometimes silver or lead, although the use of lead is less common today. Copper and antimony act as hardeners while lead is more common in the lower grades of pewter, which have a bluish tint. Pewter has a low melting point, around , depending on the exact mixture of metals. The word "pewter" is probably a variation of the word "spelter", a term for zinc alloys (originally a colloquial name for zinc). Pewter was first used around the beginning