Silicates are minerals that contain silicon atoms bonded to oxygen atoms. The basic building block for all silicate minerals is called a tetrahedron, where one silicon atom is bonded to 4 oxygen atoms (Figure 3.6). Silicate minerals also often contain other elements, such as calcium, iron, and magnesium.hosphates have a tetrahedron building block that is similar to that of the silicates. But, instead of silicon, phosphates have an atom of phosphorus, arsenic, or vanadium bonded to oxygen. Although there are many minerals in this group, most of the minerals are rare.
Neptune is the coldest planet in the Solar System. At the top of its clouds, temperatures on Neptune can dip down to 51.7 Kelvin, or -221.4 degrees Celsius. Thatâs cold! Pluto gets colder, but then, Pluto isnât a planet any more.
Neptune is one of the two planets classified as an ice giant.. Like Uranus, its composition is made up more heavily of ices than the gas giants of Jupiter and Saturn. Neptune's atmosphere is composed predominantly of hydrogen and helium, with traces of methane to create the bluish color.Unlike the terrestrial planets, Neptune and the other gas giants still hold much of the atmosphere they had at their formation. Temperature and pressure shift at different heights.nstead, the gas stretches down to the water-ammonia ocean that makes up the planet's mantle. Scientists have defined the surface of Neptune as the region where the surface pressure is equivalent to the pressure on Earth at sea level. The temperature at this surface is approximately minus 346 F (minus 201 C).