rhodiumrhombic systemrhombohedral latticerhombohedral systemribonucleic acidribosomalribosomericinus oilright handedright handed helixrigid bodyring clossurering clossure reactionring currentring opening polymerizationring opening reactionring strain theoryring structureritz rydbergy combination principlernroastroastingrock saltrock woolroentgenroentgen diffractometryroentgen rayrollingroom temperaturerootroot mean square errorroot mean square velocityrosinrotameterrotary axisrotary converterrotary evaporatorrotationrotation momentrotation viscosimeterrotational inertiarotational isomersrotational levelrotational motionrotational reflection axisrotational spectroscopyrotational spectrumrotational symmetryround bottom flaskru
