Triads Algorithm Indexing Unit Cell Parameters
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Solution Overview
Problem
Current methods for determining the unit cell parameters of crystalline solid forms, such as X-ray powder diffraction (XRPD), face challenges in distinguishing between different crystalline solid forms and identifying mixtures, due to the complexity of interpreting diffraction patterns and the non-uniqueness of unit cells.
Innovation Solution
The Triads Algorithm is employed to generate and refine unit cell parameters by selecting specific peak sets, transforming them to their reduced basis, and then to conventional cells, allowing for the identification of consistent unit cells that describe the XRPD pattern, even in low symmetry crystal structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If X-ray powder diffraction is used to determine unit cell parameters, then diffraction patterns can be obtained, but it becomes difficult to distinguish between different crystalline solid forms and identify mixtures due to pattern complexity and unit cell non-uniqueness
Solution Approach 1:
The patent segments the complex diffraction pattern analysis into distinct steps: peak identification, unit cell parameter calculation, and crystalline form comparison. By breaking down the indexing process into manageable segments, the method enables systematic distinction between different crystalline solid forms despite pattern complexity
Solution Approach 2:
The patent employs parameter changes by transforming unit cell parameters between different crystal systems (cubic, tetragonal, orthorhombic, monoclinic, triclinic) and using multiple parameter sets to describe the same crystalline form. This allows accurate distinction between different solid forms by comparing their unique parameter combinations
2Measurement precision
If conventional indexing methods are used, then unit cell parameters can be calculated, but the process is time-consuming and lacks efficiency
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing reference unit cell parameters for known crystalline solid forms in a database. Before analyzing new diffraction patterns, the system prepares reference data structures that enable rapid comparison and indexing, significantly improving processing efficiency while maintaining accuracy
Solution Approach 2:
The patent uses copying by creating and storing standardized unit cell parameter templates for different crystal systems. These template structures are replicated and adapted during indexing operations, allowing efficient parameter determination without repeating complex calculations from scratch for each new sample
3Loss of information
If single crystal diffraction is used to determine molecular scale structure, then detailed structural information can be obtained, but the requirement for large crystals with few defects limits its application
Solution Approach 1:
The patent employs this principle by using powder samples consisting of many tiny crystallites instead of requiring single large crystals. The powder diffraction method uses numerous small, easily prepared samples that can be rapidly consumed and replaced, eliminating the need for difficult crystal growth while still providing structural information through statistical averaging of many crystallite orientations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate determination of unit cell parameters, distinguishing between different crystalline solid forms and ruling out mixtures, with improved precision and efficiency in indexing powder diffraction data, particularly suited for low symmetry structures.
Implementation Method 1
X-rays are readily produced using laboratory sources and are non-destructive at sufficiently low doses. Therefore, X-ray diffraction (XRD) is the most commonly used diffraction technique.
Implementation Method 2
The radiation interacts with the electrons and/or nuclei in the sample and is scattered elastically.
Implementation Method 3
Interference within the scattered radiation creates an observable pattern that is characteristic of the molecular-scale structure of the sample.
Data Source
AI summary
The methods of the invention determine the unit cell parameters of a crystalline solid form using diffraction data and applying an algorithm. Using the algorithm, the unit cell parameters may be determined, which may allow one to distinguish between different crystalline solid forms of a substance.