Platinum-iridium alloy
Ir 10%, Pt 90%,

% composition % 
Real, long lived, electronically neutral reagent chemical.

Variation in Pt:Ir ratio.

The standard kilogram and metre in Paris are made from Pt-Ir alloy.

Platinum-iridium alloy
is defined with respect to the entities below:
The entities below are defined with respect to:
Platinum-iridium alloy
Alloy (generic)

Mono-bond type material (generic)

chemical compound molecule metal molecular science reaction mechanism ionic material acid base geometry reactivity synthesis science knowledge chemistry Lewis