Insoluble ionic compounds and insoluble metallic compounds could both have high melting points, insolubility, and no conductivity in water. Is there a way to distinguish between the two in a laboratory setting?
As solids, metals...
- conduct heat and electricity well (ionic solids do not)
- are malleable and ductile (ionic solids are not)
- have lower melting points and boiling points than ionic solids
Test these properties by...
- applying heat and a thermometer; using a conductivity apparatus (larger/chunk samples)
- hit the sample with a hammer as MaxW suggested (larger/chunk samples)
- test for relative melting/boiling points by applying equal amounts of heat (granular samples)