ents . ▁ ▁The ▁three ▁possible ▁arrang ements ▁of ▁the ▁nit ro ▁groups ▁afford ▁three ▁is om ers , ▁ 1 , 2 - d init ro ben z ene , ▁ 1 , 3 - d init ro ben z ene , ▁and ▁ 1 , 4 - d init ro ben z ene . ▁Each ▁is omer ▁has ▁the ▁chemical ▁formula ▁C 6 H 4 N 2 O 4 ▁and ▁a ▁mol ar ▁mass ▁of ▁about ▁ 1 6 8 . 1 1 ▁g / m ol . ▁ 1 , 3 - D init ro ben z ene ▁is ▁the ▁most ▁common ▁is omer ▁and ▁it ▁is ▁used ▁in ▁the ▁manufact ure ▁of ▁explos ives . ▁ ▁Properties ▁ ▁The ▁d init ro ben zen es ▁are ▁all ▁cry st all ine ▁sol ids . ▁The ▁bo iling ▁points ▁of ▁the ▁three ▁is om ers ▁are ▁relatively ▁close ; ▁however , ▁the ▁mel ting ▁points ▁significantly ▁differ . ▁ 1 , 4 - D init ro ben z ene , ▁which ▁has ▁the ▁highest ▁symmetry , ▁has ▁the ▁highest ▁mel ting ▁point . ▁ ▁References ▁▁ ▁Category : N it ro ben zen es <0x0A> </s> ▁The ▁Brun el ▁Awards ▁are ▁given ▁to ▁railway ▁companies , ▁to ▁encou rage ▁out standing ▁visual ▁design ▁in ▁railway ▁architecture , ▁graphics , ▁industrial ▁design ▁and ▁art , ▁technical ▁infrastr ucture ▁and ▁environmental ▁integration , ▁and ▁rolling ▁stock . ▁The ▁name ▁is ▁assigned ▁to ▁them ▁in ▁honour ▁of ▁Is amb ard ▁Kingdom ▁Brun el