For the best answers, search on this site https://shorturl.im/8g1Rz. Before addressing the problem, consider a regular pentagon with unit sides. Draw a diagonal d and observe that d = 2*cos(36) from one side and d = 2*cos(72) + 1 from the other so that Â½ = cos(36) - cos(72) = cos(36) - (2cosÂ²(36)-1).
Ionic compound. In chemistry, an ionic compound is a chemical compound in which ions are held together in a lattice structure by ionic bonds. Usually, the positively charged portion consists of metal cations and the negatively charged portion is an anion or polyatomic ion.hus, in an ionic bond, one 'bonder' must have a positive charge and the other a negative one. By sticking to each other, they resolve, or partially resolve, their separate charge imbalances. Positive to positive and negative to negative ionic bonds do not occur. Chemical compounds are never strictly ionic.
Definition of IONIC: Appertaining to or associated with gaseous or electrolytic ions. Ion is frequendy used interchangeably with ionic as an adjective, eg in ionic conduction, Science Dictionary The World's Largest Online Science Dictionary