👉 The word "517" is a palindrome, which means that the same word when reversed (which makes sense since it's the same thing but backwards) equals itself. However, what we're looking at here isn't just any palindrome - it's actually a chemical compound with an unusual structure!
The chemical formula for 9H pyrido[3,4 b]indole is 517. The name comes from its appearance when you mix 517.1g of indole (an organic compound made mostly of phenyl groups) with 1g of propyl alcohol. The mixture will look like this: ``` 517.1g - 1g - 516.8g ``` And the reaction will produce a 517.1g product that looks almost exactly like indole! Now, as for those crazy-looking examples you might encounter in the world of chemical engineering and industrial chemistry, they're called "hydrides" or "hydrosilicate compounds." Hydrides are compounds where an atom is bonded to a proton, but not to electrons. For example: ``` H2 (hydrogen) + NaOH -> Na + H2O ``` And for a much less common example: ``` KNO3 (sulfuric acid) + Ca(OH)2 -> CaSO4 and water ``` The "no" in the formula indicates that it
