Muon radiative energy loss (in 1.0E06 cm^2/g) in roentgenium (Rg) with Z = 111, A = [282.1691(7)] (f12.0,4f12.4) E (GeV) b_brem b_pair b_nucl b_total 2. 2.5305 0.0098 0.3523 2.8926 5. 3.5256 2.0033 0.3759 5.9047 10. 4.3398 3.5603 0.3686 8.2688 20. 5.1756 4.9600 0.3557 10.4913 50. 6.2665 7.1327 0.3413 13.7405 100. 7.0392 8.5565 0.3345 15.9302 200. 7.7406 9.8092 0.3313 17.8811 500. 8.5216 10.9485 0.3315 19.8016 1000. 8.9876 11.5475 0.3366 20.8718 2000. 9.3470 11.9761 0.3446 21.6677 5000. 9.6772 12.3346 0.3592 22.3710 10000. 9.8391 12.4977 0.3737 22.7105 20000. 9.9456 12.6058 0.3906 22.9419 50000. 10.0405 12.6844 0.4170 23.1419 100000. 10.0716 12.7173 0.4396 23.2284