[填空题]
X-rays of wavelength 0.0973 nm are directed agp,c +l +veap+t an unknown s1 y3z7ts8pdy crystal. The second diffraction maximum is recorded when sy sypz 8td731the X-rays are directed at an angle of $\mathrm{23.4°}$ relative to the crystal surface. What is the spacing between crystal planes? d = nm
