What are Nonoxide Ceramics?

for what purpose polyphosphates are used ?

3.Which of the following is not true about the basic building block of silicate minerals?     (2 نقطة) The atoms of the basic tetrahedron are strong ionically bonded together It can share oxygen atoms and be linked in a variety of ways, which results in different structures It contains one silicon atom and four oxygen atoms, each at the corner of a regular tetrahedron The negative charge of each silicate is balanced by two divalent cations The common ions in silicate have a wide range of sizes

The angle of diffraction of (220) set of planes for an FCC element occurs at 69.22° when monochromatic x-radiation having a wavelength of 0.1542 nm is used. (a) Calculate the atomic radius of the element; (b) Calculate the angle of diffraction from the set of planes (310).

What is the coordination number (CN) for each type of hole (cubic, octahedral,tetrahedral)