[DoctorDomo]

I'm looking for a solvent less polar than n-Hexane for use in liquid-liquid extractions and chromatography. This chart:
https://sites.google.com/site/miller00828/in/solvent-polarity-table
puts cyclohexane at number 1 for low polarity but other charts like this:
http://macro.lsu.edu/howto/solvents/polarity%20index.htm
contradict that and rank cyclohexane below n-Hexane. They all seem to be in agreement about pentane but that might be a bit too volatile for my purposes. When you want a solvent less polar than hexane, what do you use?

[AlphaScent]

Im pretty sure, pentane would be pretty close to the lmit.  Maybe cyclopentane??

I always understood that when in the lab working, hexane was always my go to non-polar solvent. 

I would have to say there isnt much that is less polar than hexane, pentane or cyclohexane that can be used practically...

good luck..Im sorry I do not have an answer.

[Archer]

In my experience I could get a 1,2-phenylenediamine complex of a hop acids to dissolve in hot cyclohexane (sparingly) and crystallise out. same complex would not dissolve in hexane at all.

Wouldn't longer chains offer lower polarity? Or maybe branched chains such as isooctane.

Just guessing here, hexane is as non-polar as I have ever needed. Can't you modify your other phase to get the selectivity you want?

[Enthalpy]

Neopentane (2,2-dimethylpropane) maybe? It boils at +10°C, alas.
A heavier alkane with spherical or near-spherical symmetry?
Like 2,2,3,3-tetramethylbutane, which boils at +106°C - but it melts at +101°C.

Would tetrachlorocarbon make any sense?

[DoctorDomo]

The two least polar solvents I'm familiar with are n-hexane and pet. ether 40-60. I'm not familiar with n-pentane, I think thats what I'll go with. Its low boiling point is an added benefit.

Archer: Doesn't longer chains mean greater polarizability though? Theres more Van der Waals forces going on with heavier hydrocarbons, so there will be more temporary dipole moments popping up. Symmetrically distributed branched hydrocarbons like neopentane, I have a feeling they would be really non polar.

Neopentane (2,2-dimethylpropane) maybe? It boils at +10°C, alas.
A heavier alkane with spherical or near-spherical symmetry?
Like 2,2,3,3-tetramethylbutane, which boils at +106°C - but it melts at +101°C.

Would tetrachlorocarbon make any sense?

Neopentane crossed my mind. I didn't think its BP would be that low though, that wouldn't be very practical to work with. I could keep a TLC chamber in an ice bath I suppose. 2,2,3,3-tetramethylbutane thats an interesting one, not too useful as a general, all purpose solvent lol, but I bet it can be used for some interesting specialised procedures/reactions, since a little drop in temperature should cause it to freeze, and a slight rise in temperature, to boil. Do you have experience with that one? Hadn't even heard of it until now.

Is CCl4 less polar than hexane?

Anyhow, cheers for the replies, they were pretty informative.

[Enthalpy]

Alas, very symmetric molecules tend to have a tiny liquid range. Tetrabromo- and iodo-methane are already solids.

I couldn't find quickly the liquid range for hexamethylcyclopropane and octamethylcyclobutane (pictures by Am1). The latter shows only equivalent carbons, but a symmetric C₁₂ could well be a solid. Squeezed hydrogens must also have a different affinity.

Tetramethylsilane Si(CH₃)₄ has a better liquid range (-99°C...+27°C) than neopentane.
http://www.mathesongas.com/pdfs/msds/00230205.pdf
http://www.mathesongas.com/pdfs/msds/MAT16200.pdf
Its autoignition is at unexpected +449°C, a hint that it hides its silicon.

Perfluoroneopentane melts at +73°C and sublimates before, not too good.

Perhalocycloalkanes look less interesting: carbons accessible, liquid range... Same for permethylated cycloalkanes.
http://www.apolloscientific.co.uk/downloads/msds/PC2885_msds.pdf
http://en.wikipedia.org/wiki/Octafluorocyclobutane

Sulphur hexafluoride is liquid under moderate cold or pressure. Sulphur hexachloride, still a gas, appears to exist commercially despite not being so stable
http://www.trivenichemical.com/hexachloride1.html

A few metals (W, and U) have liquid fluorides but the metal looks accessible. Hexachlorides are solids.

Polar halides? I suppose it, too. All halogens are equivalent in the compounds I suggested, but I suppose that their apex has a different affinity than their sides.

[Enthalpy]

Hexamethyl-disilane (picture) is liquid @1atm between +14°C and +114°C (better than the hydrocarbon homologue), it shows only methyl groups, suppliers exist.

Found no liquid range for 2,2,3,3,4,4-hexamethyl-pentane (picture). It shows only methyl groups.

Liquid xenon? It needs cold and pressure
http://encyclopedia.airliquide.com/images_encyclopedie/VaporPressureGraph/Xenon_Vapor_Pressure.GIF
and in case it dissolves your compound, it could be non-polar 

[PhDoc]

Albeit the hydrocarbons have been well noted, please keep in mind solvents need not be molecular. Liquified noble gases will not exhibit the London Forces demonstrated by hydrocarbons. The dielectric constant for hexane is 1.890, however for liquid helium is approximately 1.055, i.e. nearly equivalent to a vacuum. Liquid neon and argon have dielectric constants of approximately 1.5 units, still lower than hexane.

Alas, someone already mentioned liquid xenon. 

[PhDoc]

Cubane might make an interesting solvent for your extraction, at least in principle. You do present a quite stimulating problem.

[Corribus]

Something tells me he isn't going to be using liquid helium for an extraction or chromatography.

Beyond the point, I also find it curious when organic chemists talk about "polarity" of a solvent. (I don't mean that disparagingly, mind. I use it, too, in informal conversation.) What exactly is your metric for "polarity"? It seems from the context of the OP that dipole moment is the intended metric, but that clearly is a poor value to use as far as practical chemical procedures goes - because many properties of a solvent depend on far more than just dipole moment.

[orgopete]

I agree that polarity isn't terribly meaningful. I did not find the original post meaningful. It would have been more useful if they presented the actual problem rather that what they assumed would be the solution. Although the generalization of like dissolves like is a useful rule of thumb, it does not describe actual solubility, which is what the poster may have been asking about. Polarity and elution power are not a linear correlation.