Lattice parameter of silicon
UnitsMeasured
= 5.431 020 511(89) × 10−10 m
- Value
- 5.431 020 511 × 10−10 m
- Standard uncertainty
- 8.9 × 10−18 m
- Relative uncertainty
- 1.6 × 10−8 (16 parts per billion)
- Status
- Measured
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
Use in a calculation
# lattice parameter of silicon, CODATA 2022 (NIST)
lattice_parameter_of_silicon = 5.431020511e-10 # m, standard uncertainty 8.9e-18
# SciPy: scipy.constants.physical_constants['lattice parameter of silicon']What it is
The edge length of the cubic unit cell of an ideal silicon crystal at 22.5 °C in vacuum. Measured with combined X-ray and optical interferometry, it links X-ray wavelengths to the metre and was central to counting atoms in silicon spheres for the Avogadro constant.
Equations
- (220) lattice spacing
In other units
| Unit | Value | |
|---|---|---|
| CGS (cm) | 5.431 020 511 × 10−8 | |
| nm nanometre | 0.543 102 0511 | |
| pm picometre | 543.102 0511 | |
| fm femtometre | 543 102.0511 | |
| Å ångström | 5.431 020 511 | |
| a₀ bohr (atomic unit) | 10.263 141 35 | unit is itself measured |
Converted with ConstantID's unit table; digits are rounded to the precision of the value, and a long exact value is rounded only for display. The relative uncertainty is unchanged by conversion to an exactly defined unit.
How the value changed, 1998–2022
Each point is one CODATA adjustment, plotted as its difference from the 2022 value; the bars show one standard uncertainty (an arrowhead means the bar runs off the chart).
Relative uncertainty
| CODATA | Value (uncertainty) | Relative uncertainty | Change from previous |
|---|---|---|---|
| 2022 | 5.431 020 511(89) × 10−10 | 1.6 × 10−8 | +0.0 σ of 2018 |
| 2018 | 5.431 020 511(89) × 10−10 | 1.6 × 10−8 | +0.1 σ of 2014 |
| 2014 | 543.102 0504(89) × 10−12 | 1.6 × 10−8 | +0.0 σ of 2010 |
| 2010 | 543.102 0504(89) × 10−12 | 1.6 × 10−8 | −1.0 σ of 2006 |
| 2006 | 543.102 064(14) × 10−12 | 2.6 × 10−8 | −2.9 σ of 2002 |
| 2002 | 543.102 122(20) × 10−12 | 3.7 × 10−8 | +2.1 σ of 1998 |
| 1998 | 543.102 088(16) × 10−12 | 2.9 × 10−8 |
“Change from previous” is the shift in the value divided by the standard uncertainty of the previous adjustment. Earlier values are converted into the current unit where NIST changed it (for example J s to J Hz⁻¹).