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.
Ionic bonds are formed when there is a strong difference between the electronegativity of the two atoms involved. Also, a metal is almost ALWAYS involved in ionic bonding. In fact, I can't think of any ionic compounds not involving metals.A good example of ionic bonding is common table salt, sodium chloride.onic bonds are formed when there is a strong difference between the electronegativity of the two atoms involved. Also, a metal is almost ALWAYS involved in ionic bonding. In fact, I can't think of any ionic compounds not involving metals. A good example of ionic bonding is common table salt, sodium chloride.