[eglaud]

So I punched in 3,3,6,6-tetraethyl-4-octyne on one of those nomenclature sites (http://www.openmolecules.org/name2structure.html) and saw what it looked like. I was curious about why these numbers repeat themselves? I see that 3,6-tetraethyl-4-octyne is not recognized, yet when I change the tetra to a di then this works. Do those repeating numbers have anything to do with these prefixes? Thanks.

[eglaud]

And while we're at it, can anyone explain why the diagram on that website only sees to have a chains of 6 carbons and not 8, like the octyne would suggest? Thanks

[eglaud]

And while we're at it, can anyone explain why the diagram on that website only sees to have a chains of 6 carbons and not 8, like the octyne would suggest?

The 3D model looks different, is that what those double lines in the middle of the 2D mean, that there are two carbons there?

[Borek]

Tetraethyl means there are four ethyls attached, you need to list position for every one, hence 4 digits (actually numbers) at the beginning of the name. When you change tetra- to di- there are two ethyls only, so two numbers are enough to describe their positions.

Diagram shows chains of eight atoms, not six.

Double lines (actually triple line) means there is a triple bond there, that's what -yne means.

[Vidya]

So I punched in 3,3,6,6-tetraethyl-4-octyne on one of those nomenclature sites (http://www.openmolecules.org/name2structure.html) and saw what it looked like. I was curious about why these numbers repeat themselves? I see that 3,6-tetraethyl-4-octyne is not recognized, yet when I change the tetra to a di then this works. Do those repeating numbers have anything to do with these prefixes? Thanks.

Remember in  nomenclature every substituent has a number,it is a rule .In this case four substituents and two are on 3 and two are on 6.You have to include  number of each substituent ...so four numbers must be there ...3,3,6,6-