Calculate the theoretical density, in g/cm3, of an AX compound given the following information: The ionic radii of the cation and anion are 0.077 and 0.140 nm, respectively, and their atomic weights are 55.8 and 16.0 g/mol, respectively.

Hint: predict the crystal structure by determining the expected coordination for these ions, based on their radii ratio.

Pegmatites are igneous rocks in which the individual minerals are very large. typically, the minerals are all light-colored quartz, feldspar and muscovite. if you were given a black and white photograph of a pegmatite in a quarry (where the rock has been blasted and broken), what physical properties could you use to identify those three minerals in this hypothetical photo? describe each mineral and the specific diagnostic properties. be specific.