Question
Identify isomorphous and polymorphous substances in the following:
$K _2 SO _4$, graphite, $\beta$-quartz, $Na _2 SeO _4, CaCO _3$, diamond, cristobalite, $C _5 NO _3$.
$K _2 SO _4$, graphite, $\beta$-quartz, $Na _2 SeO _4, CaCO _3$, diamond, cristobalite, $C _5 NO _3$.