: an isomer that is a stereoisomer of a compound having two or more chiral centers and that is not a mirror image of another stereoisomer of the same compound â
A compact disc is a deceptively simple looking device considering the technology required to make it. 1  CDs consist of three layers of materials: 2  A base layer made of a polycarbonate plastic. 3  A thin layer of aluminum coating over the polycarbonate plastic. 4  A clear protective acrylic coating over the aluminum layer.
The most common size of CD-ROM is 120 mm in diameter, though the smaller Mini CD standard with an 80 mm diameter, as well as shaped compact discs in numerous non-standard sizes and molds (e.g., business card-sized media) are also available. Data is stored on the disc as a series of microscopic indentations.