Rare-earth ultraphosphate (RP₅O₁₄) framework materials are potential host media for nuclear waste storage, since cages within their nanoporous structures have volumes that match well those of prospective guests such as uranium or plutonium ions. Good volume matches of host cages and guest compounds are nonetheless not the only structural requirement for ensuring viable nuclear waste storage. Host structures also need to be stable enough to withstand the typical environmental conditions of long-term storage of spent nuclear fuel. To this end, the nanoporous cage topologies of neodymium and gadolinium ultraphosphate, NdP₅O₁₄ and GdP₅O₁₄, are investigated as a function of temperature. Topological analysis shows that, while both compounds are essentially isostructural, thus displaying the same type of cage structures, the cage volumes of NdP₅O₁₄ are significantly larger than those of GdP₅O₁₄, with one stark exception. This exception concerns the smallest cage of NdP₅O₁₄, whose 8/4 topology lacks structural cross-linking that would otherwise give it much more strength. This 'squashed' cage appears to owe its origins to the specific nature of crystallographic twinning in NdP₅O₁₄, which causes strain that needs alleviating; squashing the 8/4 cage in NdP₅O₁₄ would be the most susceptible option towards this end, since its cage manifests the weakest structural construct. GdP₅O₁₄ succumbs to a gradual contraction of its 8/4 cage only with increasing temperature above 300 K; this is well below its second-order monoclinic-to-orthorhombic phase transition at 420–430 K; which is 420 K for NdP₅O₁₄. Fortunately, the volumes of heavy metal ions that arise from spent nuclear fuels do not match the size requirements of cages with 8/4 topology in RP₅O₁₄ hosts needed for encapsulation; otherwise, radiation leakage of such containment would present a risk. Both NdP₅O₁₄ and GdP₅O₁₄ would therefore seem to offer good prospects as host media for nuclear waste storage.

稀土超磷酸盐（RP ₅ O ₁₄）骨架材料是核废料存储的潜在宿主介质，因为其纳米多孔结构内的笼子的体积与铀或p离子等潜在客体的体积非常匹配。但是，主机笼和客体化合物的良好体积匹配并不是确保可行的核废料储存的唯一结构要求。主机结构还必须足够稳定，以承受乏核燃料长期存储的典型环境条件。为此，钕和ado超磷酸盐，NdP ₅ O ₁₄和GdP ₅ O ₁₄的纳米孔笼形拓扑被研究为温度的函数。拓扑分析表明，尽管两种化合物基本上都是同构结构，因此显示出相同类型的笼状结构，但NdP ₅ O ₁₄的笼状体积明显大于GdP ₅ O ₁₄的笼状体积，唯一的例外。此例外涉及NdP ₅ O ₁₄的最小笼子，该笼子的8/4拓扑结构缺少结构性交联，否则会使其强度更高。这种“压扁”的笼子似乎归因于NdP ₅ O ₁₄中晶体孪晶的特殊性质，这导致需要缓解的应变。挤压NdP _5中的8/4笼O ₁₄是为此目的最容易受到影响的选择，因为它的笼子表现出最弱的结构构造。GdP ₅ O ₁₄仅在温度升高至300  K以上时才逐渐收缩其8/4笼；这远低于其在420–430  K的二阶单斜晶向斜方晶相转变； 对于NdP ₅ O ₁₄为420K 。幸运的是，由乏核燃料产生的重金属离子的体积不符合封装所需的RP ₅ O ₁₄主机中具有8/4拓扑结构的笼子的尺寸要求。否则，这种容器的辐射泄漏会带来危险。两者均为NdP ₅因此，O ₁₄和GdP ₅ O ₁₄作为核废料存储的宿主介质似乎具有良好的前景。