13-Letter Words Matching ________R___L

There are 23 13-letter words that match ________R___L. 8 are common words, such as CONTROVERSIAL and HEMISPHERICAL. A rarer one is SEMIEMPIRICAL. In this set, I is the most frequent open letter (23 words). 3 words contain a doubled letter.

Full list 23

controversialhemisphericalnoncommercialnonelectricalnonreciprocalnontheatricalprehistoricalunsymmetricalantidiarrhealeconometricalgravimetricalhydrometricalnonhistoricalphotometricalsociometricalbathymetricalbioelectricalhypermetricalinterneuronalisoproterenolmyoelectricalnonhystericalsemiempirical

About this list

Words
23 (8 common words)
Common example
controversial
Rare example
semiempirical
Doubled letters
3
Ending in S
0
Most frequent letter
I (23)

Questions

How many 13-letter words matching ________r___l are there?

23. 8 of them are common words.

What is a common example?

CONTROVERSIAL is among the common words in this set.