Lattice Parameters of Cerous Magnesium Nitrate Hydrate at 4.2, 78, and 302°K

The lattice constants $a$ and $c$ (hexagonal cell) of cerous magnesium nitrate hydrate, Ce₂Mg₃(NO₃)₁₂·24H₂O have been determined at 302 ± 1, 78, and 4.2°K. The Bond precision technique was used with $\mathrm{Co}{\mathrm{K\alpha }}_1$ radiation $\text{(λ\hspace{0.17em}=\hspace{0.17em}1.788965)}$ and $\mathrm{Mo}{\mathrm{K\alpha }}_1$ radiation $\text{(λ\hspace{0.17em}=\hspace{0.17em}0.709300)}$ with several samples. Accuracy was limited by unavoidable damage done to the crystals in cooling to cryogenic temperatures. Values obtained for $a$ and $c$ are $\text{a\hspace{0.17em}=\hspace{0.17em}10.9857\hspace{0.17em}±\hspace{0.17em}0.0009, c\hspace{0.17em}=\hspace{0.17em}34.068\hspace{0.17em}±\hspace{0.17em}0.006}$ at 4.2°K; $\text{a\hspace{0.17em}=\hspace{0.17em}10.9885\hspace{0.17em}±\hspace{0.17em}0.0008, c\hspace{0.17em}=\hspace{0.17em}34.106\hspace{0.17em}±\hspace{0.17em}0.003}$ at 78°K; $\text{a\hspace{0.17em}=\hspace{0.17em}11.0354\hspace{0.17em}±\hspace{0.17em}0.0001, c\hspace{0.17em}=\hspace{0.17em}34.640\hspace{0.17em}±\hspace{0.17em}0.001}$ at 302 ± 1°K.