▁and ▁also ▁to ▁the ▁in organ ic ▁carbon ates . ▁ ▁Mon om ers ▁of ▁poly car bon ate ▁( e . g . ▁Lex an ) ▁are ▁linked ▁by ▁carbon ate ▁groups . ▁These ▁poly car bon ates ▁are ▁used ▁in ▁e y eg lass ▁l enses , ▁compact ▁disc s , ▁and ▁bullet proof ▁glass . ▁Small ▁carbon ate ▁est ers ▁like ▁dim eth yl ▁carbon ate , ▁eth yl ene ▁carbon ate , ▁pro py l ene ▁carbon ate ▁are ▁used ▁as ▁sol vent s , ▁ ▁dim eth yl ▁carbon ate ▁is ▁also ▁a ▁m ild ▁m eth yl ating ▁agent . ▁ ▁Struct ures ▁ ▁Car bon ate ▁est ers ▁have ▁plan ar ▁O C ( OC ) 2 ▁ ▁cores , ▁which ▁conf ers ▁rig id ity . ▁ ▁The ▁unique ▁O = C ▁bond ▁is ▁short ▁( 1 . 1 7 3 ▁Å ▁in ▁the ▁dep icted ▁example ), ▁while ▁the ▁C - O ▁b onds ▁are ▁more ▁ ether - like ▁( the ▁bond ▁distances ▁of ▁ 1 . 3 2 6 ▁Å ▁for ▁the ▁example ▁dep icted ). ▁ ▁Car bon ate ▁est ers ▁can ▁be ▁divided ▁into ▁three ▁struct ural ▁classes : ▁a cyc lic , ▁cy clic , ▁and ▁polym er ic . ▁The ▁first ▁and ▁general ▁case ▁is ▁the ▁a cyc lic ▁carbon ate ▁group . ▁ ▁Organ ic ▁subst itu ents ▁can ▁be ▁identical ▁or ▁not . ▁ ▁Both ▁ali ph atic ▁or ▁a rom atic ▁subst itu ents ▁are