Isomerism is the phenomenon whereby certain compounds, with the same molecular formula, exist in different forms owing to their different organisations of atoms. The concept of isomerism illustrates the fundamental importance of molecular structure and shape in organic chemistry.
By signing the nuclear deal, Iran has given up that nuclear umbrella for as long as two decades and made the case for the United States to further strengthen the conventional military capacities of Israel and the GCC.
Nuclear dangers as Iran deal deadline nears 02:29. Talks aimed at reaching a deal over Iran's nuclear program are going down to the wire. The stakes are huge -- for Iran, the United States, Israel, the wider Middle East and beyond.