If you switch any two substituents, that will change the stereochemistry. If you do a second switch (any two), you are back to the original stereochemistry. You can try it out with substituent 4 in the back, and seeing what switching around 1, 2, and 3 do to the clockwise or counterclockwise orientation (i.e. whether it is R or S).
Two switches (for example ...
Based on the OP’s two questions and the OP’s several comments, the OP wants to know if there is a commercially available liquid which, at 23°C, is transparent in the range 380 to 700 nm. As the OP stated in a comment, the liquid should be “not poisonous and can be used as gap fillers in refractometers (gap between prism and stones).”
In gemological testing ...
Solutions of phosphorous in carbon disulfide are not only smelly and toxic, but they're hideously prone to catching fire. Methyene iodide is carcinogenic. Selenium and its compounds are toxic and notoriously evil-smelling.
Because we're playing around in the periodic table's bad neighborhood, high RI liquids are uniformly, extremely unpleasant.
Sucrose or glucose in H2O = approx 1.4-1.5 depending on composition and concentration
Glycerol = 1.473
Toluene = 1.5
Chlorobenzene = 1.524
Getting higher than that without very high flammability/toxicity/reactivity is hard
To complement @blu_potatos's answer, there are some other contenders having refractive index greater than 2
Arsenic di/trisulfide and sulfur and/or selenium and/or mercuric sulfide in arsenic tribromide solvent having refractive index ranging from 2.0 to 2.07 (arsenic tribromide seem to attack the lead-glass prisms of refractometers, corroding metal, ...
Definition of refractive index:
If n>2 then this means that the velocity of light in the material is less than half than in vacuum so there must be a strong interaction with the material.
One of the highest refractory index in liquids is 1.79(20°C) possessed by a solution of sulfur in methylene iodide($CH_2I_2$). Liquids are less dense ...