Maynard-Casely Helen E, Hester James R, Brand Helen E A
Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC 2232 Australia.
Australian Synchrotron, ANSTO, 800 Blackburn Road, Clayton 3168, Australia.
IUCrJ. 2020 Jul 29;7(Pt 5):844-851. doi: 10.1107/S2052252520007460. eCollection 2020 Sep 1.
In the light of NASA's mission, the solid-phase behaviour of methane and nitrogen has been re-examined and the thermal expansion coefficients of both materials have been determined over their whole solid temperature range for the first time. Neutron diffraction results indicate that the symmetric 3 space group is the best description for the α-nitrogen structure, rather than the long-accepted 23. Furthermore, it is also observed that β-nitrogen and methane phase I show changes in texture on warming, indicating grain growth.
鉴于美国国家航空航天局的任务，对甲烷和氮的固相行为进行了重新研究，并首次在整个固体温度范围内测定了这两种材料的热膨胀系数。中子衍射结果表明，对称的Pm3空间群是对α-氮结构的最佳描述，而不是长期以来公认的P213。此外，还观察到β-氮和甲烷I相在升温时织构发生变化，表明晶粒在生长。
