CaTiO3aa

CaTiO3aa is a chemical formula representing calcium titanate with a specific, though undefined, structural or compositional variation denoted by "aa". Calcium titanate, commonly known as perovskite, has the general chemical formula ABX3. In this case, Calcium (Ca) is the A-site cation, Titanium (Ti) is the B-site cation, and Oxygen (O) is the X-site anion. The designation "aa" appended to CaTiO3 suggests a modification or a specific phase of calcium titanate that is not immediately obvious from standard nomenclature. It could potentially refer to a particular crystallographic defect, doping concentration, or an ordered arrangement of vacancies or interstitials. Without further context or clarification, the precise nature of the "aa" modification remains ambiguous.

Calcium titanate itself is a mineral that crystallizes in the perovskite structure, named after the mineral perovskite (CaTiO3). This structure is cubic at high temperatures but can distort to orthorhombic, tetragonal, or monoclinic phases at lower temperatures, depending on the specific composition and pressure. Calcium titanate is known for its dielectric properties and is used in various electronic applications, including capacitors and sensors. The "aa" notation might point to a particular polymorph or a defect state that influences these properties. Further research into the specific literature or database where "CaTiO3aa" is encountered would be necessary to understand its exact meaning and implications.