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 orbits around the sun every 165 years at an average distance of 2.8 billion miles (4.5 billion km). It spins on its own axis every 16 hours compared to 24 hours on Earth. Due to its far distance from the sun Neptune has an extremely cold outer atmosphere with temperatures averaging around -220C (-364F).Temperatures at its center rise to around 5000C (9000F). Neptune has 13 known satellites, the largest being Triton (picture right) which has a diameter of around 1,681 miles (2,705 km).ue to its far distance from the sun Neptune has an extremely cold outer atmosphere with temperatures averaging around -220C (-364F). Temperatures at its center rise to around 5000C (9000F).