Mendeleev

1.1.0 · active · verified Tue Apr 14

Mendeleev is a Python library that provides a convenient API for accessing various properties of elements, ions, and isotopes from the periodic table. It includes functionalities for data manipulation, integration with pandas for bulk data access, and visualization capabilities using libraries like Bokeh and Plotly. The library is actively maintained, with its current version being 1.1.0.

Warnings

breaking Version 1.1.0 introduces a bump in the `numpy` dependency to `^2.0`. Projects relying on an older `numpy` version (e.g., `numpy<2.0`) will experience breakage when upgrading `mendeleev` to 1.1.0.
Fix: Ensure your environment's `numpy` version is 2.0 or higher. You may need to update `numpy` explicitly: `pip install 'numpy>=2.0'`.
gotcha Mendeleev ships with its own SQLite database. While direct interaction is possible, the recommended way to access data in bulk is through functions in the `mendeleev.fetch` module (e.g., `fetch_table`). Bypassing these functions might lead to issues if the internal database schema changes in future versions.
Fix: Always use `from mendeleev.fetch import fetch_table` and other `fetch_` functions for bulk data access to ensure compatibility and stability.
gotcha Prior to v0.17.0, there were known compatibility issues with the `fetch_table` function when used with certain major versions of `pandas` and `sqlalchemy`. Although resolved in v0.17.0, users on older `mendeleev` versions might still encounter these problems.
Fix: Upgrade `mendeleev` to version 0.17.0 or higher to benefit from improved compatibility with `pandas` and `sqlalchemy`.
gotcha In earlier versions (specifically around v0.16.1 and v0.16.2), there were reported issues with `ImportErrors` not being raised correctly or general import errors. While fixed, this suggests a historical fragility in the import mechanism that users on very old versions might encounter.
Fix: Ensure you are using `mendeleev` v0.16.2 or newer to avoid potential import-related issues.

Install

pip install mendeleev Install latest stable version

Imports

Element objects directly (e.g., Si, Fe)
```
from mendeleev import Si, Fe
```
Allows direct access to common elements as objects.
element function
```
from mendeleev import element
```
The `element` function is exposed directly at the top-level package, not within a submodule like `mendeleev.mendeleev`.
fetch_table function
```
from mendeleev.fetch import fetch_table
```
Used for retrieving bulk data as pandas DataFrames from the internal database.

Quickstart

This quickstart demonstrates how to import the `element` function and retrieve an element's properties such as name, atomic number, atomic weight, electronic configuration, and electronegativity.

from mendeleev import element

# Get an element by symbol
si = element("Si")

# Access its properties
print(f"Element: {si.name} ({si.symbol})")
print(f"Atomic Number: {si.atomic_number}")
print(f"Atomic Weight: {si.atomic_weight}")
print(f"Electronic Configuration: {si.econf}")
print(f"Pauling Electronegativity: {si.electronegativity(scale='pauling')}")

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