The file (available in Supplementary Information) consists of string information with the element symbol and its electron configuration. These two columns should be used for indexing, not as a part for feature calculation. The first listed property is atomic weight numbers with three digits after decimal point for each atomic weight providing consistency in calculations. Figure shows the principle used for generating features from element properties. This could be done in Python, MATLAB, or even simpler environments, such as Excel, using index and match functions. The features can be direct values of elements from the formula, but most commonly, the element values are weighted according to atomic percent or index of the element. Molar mass from atomic weights is the simplest form of a descriptor. While some features have obvious physical meaning (e.g., molar mass), the other features such as ratio of atomic weights, difference of atomic weights, or average of atomic weights might not carry an immediate scientific insight, but could be helpful for rationalizing the trends in problems involving element doping, for example.