The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Thermal decomposition of hydrated salts of copper and nickel. VII. Fluoride, chloride, and iodide of nickel》. Authors are My, Le Van; Perinet, Guy; Bianco, Pierre.The article about the compound:Nickel(ii)fluoridetetrahydratecas:13940-83-5,SMILESS:[H]O[H].[H]O[H].[H]O[H].[H]O[H].[Ni+2].[F-].[F-]).HPLC of Formula: 13940-83-5. Through the article, more information about this compound (cas:13940-83-5) is conveyed.
cf. preceding abstract The F-, Cl-, and I- of Ni were heated from ambient temperature to 750° at 5°/hr. Pyrolysis in air led to the formation of oxides. The dehydration of I- gave an anhydrous salt directly, but the removal of the last mol. of H2O was difficult in all cases.
In addition to the literature in the link below, there is a lot of literature about this compound(Nickel(ii)fluoridetetrahydrate)HPLC of Formula: 13940-83-5, illustrating the importance and wide applicability of this compound(13940-83-5).
Reference:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider