11. They are isoelectronic , but fluoride is bigger because its nuclear charge is lower. 12. This ion is isoelectronic with the hydrogen molecule. 13. Further catenation is rare, although ( isoelectronic with carbonate and nitrate ) is known. 14. The "'tetrafluoroammonium "'isoelectronic with tetrafluoromethane and the tetrafluoroborate anion. 15. It is isoelectronic with N 2. 16. BF is isoelectronic with carbon monoxide ( CO ) and so could form similar compounds to metal carbonyls. 17. With fluoride, PF 5 forms PF 6 ", an anion that is isoelectronic with SF 6. 18. The tetramethylborate ion has a negative charge and is isoelectronic with neopentane, tetramethylsilane, and the tetramethylammonium cation. 19. It is isoelectronic with a chlorine " atom ", also undergoing pairing to form Cl 2 molecules. 20. Has a number of canonical resonance forms making it isoelectronic with bisulfite ion,, which has a similar structure.
