Another question - How are chemicals named?

[RyanJ]

Hi everyone (Again!)!

 

I've been wondering about this for a long time.

 

I know that things like 1-methyl-2,4,6-trinitromethylbenzene (AKA TNT) is a structural formula - those I know a bit about already

 

 

What I really want to know is how does a chemist decide which element goes at the start of the name. Take Sodium Oxide, why decided that the sodium should go first? Are there rules that decide what element / component should go first?

 

 

Cheers,

 

Ryan Jones

[jdurg]

Positively charge ions always are named first, and negatively charged monatomic ions always end in -ide. So sodium sulfide says that you have a negatively charged sulfur and a positively charged sodium. With polyatomic ions, it all depends on the oxidation state of the least prevalant element. So for NO2 and NO3, you have nitrite for the lower oxidation state, and nitrate for the higher oxidation state of nitrogen.

 

Either way, however, the positively charged species is named first and the negatively charged one is last.

[RyanJ]

Positively charge ions always are named first' date=' and negatively charged monatomic ions always end in -ide. So sodium sulfide says that you have a negatively charged sulfur and a positively charged sodium. With polyatomic ions, it all depends on the oxidation state of the least prevalant element. So for NO2 and NO3, you have nitr[b']ite[/b] for the lower oxidation state, and nitrate for the higher oxidation state of nitrogen.

 

Either way, however, the positively charged species is named first and the negatively charged one is last.

 

Ah, I see - so there is a pattern. Highest electro-positive element first and go from there?

 

How about organic compounds, I know these are a bit more complex as there seem to be a hell of a lot more of them but do you have any insight into those? They seem to start from a fixed point in the chanin or sequence and move along from there but any insight would be much appreciated

 

Cheers,

 

Ryan Jones

[MulderMan]

look up IUPAC nomenclature, sorry i cant offer more than the name of it!

[akcapr]

What exactly do you not understand about the organic nomenclature?

[RyanJ]

What exactly do you not understand about the organic nomenclature?

 

The sequence of the elements in its name and basically how do they decide which carbon for example is the "2" in 1-methyl-2,4,6-trinitromethylbenzene?

 

 

Cheers,

 

Ryan Jones

[YT2095]

well it usualy goes clockwise around the benzene ring, so if take something a little more simple, like 2,4,6 trichlorophenol (tcp) the OH is always considered position 1, then the other nodes around the ring are 2 3 4 5 6.

so tcp will have a chlorine either side of the OH and one directly opposite at position 4.