# Tag Info

### What "physical method" does Feynman refer to in The Feynman Lectures on Physics (Vol 1)

In the mid-20th century, instrumental methods available to organic chemists were nuclear magnetic resonance (NMR), infrared spectroscopy (IR), mass spectrometry (MS) and X-ray diffraction (...
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### Why is scandium not in Group 13 despite being once called "eka-boron"?

Note that the periodic table we are seeing today is not the same during Mendeleev's period. If you look at the old periodic table, you will find scandium below boron. So, Mendeleev predicted correctly....
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Accepted

### Why is scandium not in Group 13 despite being once called "eka-boron"?

In older forms of the Periodic Table, boron was not necessarily far away from what we now call scandium. Mendeleev himself used a form where what we now call the fourth and later periods were set up ...
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Midgley tried various compounds, especially $\ce{(C2H5)2Se}$, $\ce{(C2H5)2Te}$, $\ce{(C2H5)4Sn}$, and $\ce{(C2H5)4Pb}$, which all work as anti-knock agents with similar mechanisms. The oldest method ...