This fluid, which has a high electrical conductivity, is sometimes called a water–ammonia ocean.[56] The bulk compositions of Uranus and Neptune are very different from those of Jupiter and Saturn, with ice dominating over gases, hence justifying their separate classification as ice giants.
The total mass of ice in Uranus's interior is not precisely known, as different figures emerge depending on the model chosen; however, it must be between 9.3 and 13.5 Earth masses.[8][54] Hydrogen and helium constitute only a small part of the total, with between 0.5 and 1.5 Earth masses.[8] The remainder of the mass (0.5 to 3.7 Earth masses) is accounted for by rocky material.[8]