The GetProperty( name ) command returns the property if name is a property name in the ScientificConstants package. Otherwise, an error is returned.

The expression sequence returned consists of the property name and an equation of the form $\'\mathrm{isotopic}\'=$ true or false.

If 'isotopic' = false, the property is an element property. If 'isotopic' = true, the property is an isotope property.

$\mathrm{with}\left(\mathrm{ScientificConstants}\right)\:$

$\mathrm{GetProperty}\left(\mathrm{atomicweight}\right)$

$\mathrm{atomicweight},\mathrm{isotopic}=\mathrm{false}$

$\mathrm{GetProperty}\left(\mathrm{atomicmass}\right)$

$\mathrm{atomicmass},\mathrm{isotopic}=\mathrm{true}$