The formula for calculating the index of refraction is expressed as
n = c/v
where
n = index of refraction
c = speed of light in vacuum = 3 x 10^8 m/s
v = speed of light in the medium = 131,050,292.04 m/s
By substituting these values into the formula,
n = 3 x 10^8/131050,292.04
n = 2.3
The index of refraction is 2.3