1 4 ▁hyd rides ▁follow ▁the ▁formula ▁X n H 2 n + 2 , ▁the ▁same ▁formula ▁for ▁the ▁al kan es . ▁ ▁Many ▁other ▁group ▁ 1 4 ▁hyd rides ▁are ▁known . ▁Car bon ▁forms ▁a ▁huge ▁variety ▁of ▁hydro car b ons ▁( with ▁prop ane ▁and ▁but ane ▁following ▁m eth ane ▁and ▁eth ane ▁among ▁the ▁al kan es , ▁but ▁also ▁including ▁al ken es , ▁alk yn es , ▁cy clic ▁and ▁branch ed ▁comp ounds , ▁as ▁well ▁as ▁a rom atic ▁hydro car b ons ▁such ▁as ▁ben z ene , ▁to lu ene ▁and ▁lim on ene ), ▁whose ▁study ▁forms ▁the ▁core ▁of ▁organ ic ▁chem istry . ▁▁ ▁Al ong side ▁hydro gen , ▁carbon ▁can ▁form ▁comp ounds ▁with ▁the ▁chem ically ▁similar ▁hal og ens , ▁forming ▁h alo alk anes . ▁The ▁simplest ▁of ▁this ▁series , ▁the ▁hal om eth anes , ▁contain ▁comp ounds ▁such ▁as ▁dich lor om eth ane ▁and ▁i odo form . ▁Other ▁such ▁important ▁chemical s ▁include ▁vin yl ▁ch lor ide , ▁which ▁is ▁used ▁in ▁the ▁production ▁of ▁P VC . ▁ ▁The ▁other ▁group ▁ 1 4 ▁elements ▁have ▁a ▁lower ▁t endency ▁to ▁c aten ate . ▁Sil anes ▁Sin H 2 n + 2 ▁are ▁known ▁for ▁n ▁= ▁ 1 – 8 ▁( ther mal ▁stability ▁decre asing ▁as ▁n ▁increases ), ▁as ▁are ▁cy clos il anes ▁Si 5 H 1 0