Frequently Asked Questions
How many atoms are in each unit cell?
A face-centered cubic cell has 4 atoms, a body-centered cubic cell has 2, and a simple cubic cell has 1. Other structures can be entered as a custom value.
What units does the edge length use?
Enter the cubic edge length in picometers. The calculator converts it to centimeters internally to return density in grams per cubic centimeter.
Why compare calculated and measured density?
A match confirms the assumed crystal structure, while a mismatch can reveal vacancies, impurities, or a different packing arrangement.
What are the packing efficiencies of FCC, BCC, and simple cubic?
Face-centered cubic (FCC) is the most efficient of the three, filling about 74% of space with 4 atoms per cell. Body-centered cubic (BCC) fills about 68% with 2 atoms per cell. Simple cubic fills only about 52% with 1 atom per cell. For a given atom, higher packing efficiency generally means a shorter edge relative to atom size and a higher density.
Can I find the edge length from a known density?
Yes. Rearrange the density formula ρ = n × M / (N<sub>A</sub> × a³) into a³ = n × M / (N<sub>A</sub> × ρ), then take the cube root to get the edge length a. In this tool you can back-check an edge length by entering the structure and molar mass and comparing the calculated density with the measured one.
Provided by AllCalculators.io
Free online calculators for everyday. No registration required.
Estimates for informational purposes only.
Important Disclaimer: Estimates for informational purposes only.
This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.