With iodide, the solvate $\ce{NaI \cdot 3(CH3)2CO}$ can be formed, in which each $\ce{Na+}$ is coordinated by 6 acetone ligands via oxygen lone pairs, and the $\ce{I-}$ ions fill in the gaps between these octahedral units, being surrounded by the methyl groups of the acetones.
Randomization is a sampling method used in scientific experiments. It is commonly used in randomized controlled trials in experimental research.
The term randomized trials omits mention of controls and can describe studies that compare multiple treatment groups with each other (in the absence of a control group). This type of randomization can be combined with stratified randomization, for example by center in a multicenter trial, to ensure good balance of participant characteristics in each group.. 2  A special case of permuted-block randomization is random allocation, in which the entire sample is treated as one block.