X-rays of wavelength 1.936 Å are diffracted by a body-centered cubic metal lattice. The radius of the metal atom is 1.260 Å. Calculate the diffraction angle of the second-order () reflection in degrees to 3 significant figures.
X-rays of wavelength 0.1057 nm are diffracted by a cubic metal lattice, producing a second-order () reflection at . The metal atom has a radius of 1.680 Å and molar mass of 210 g/mol. Calculate the density of the metal to 3 significant figures.