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.
Dark, cold and whipped by supersonic winds, Neptune is the last of the hydrogen and helium gas giants in our solar system. More than 30 times as far from the sun as Earth, the planet takes almost 165 Earth years to orbit our sun. In 2011 Neptune completed its first orbit since its discovery in 1846.