Periodic Table |
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| What is the Periodic Table Showing? | Periodicity |
The INTERNET Database of Periodic Tables
There are thousands of periodic tables in web space, but this is the only comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Mark R. Leach Ph.D. The database holds information on periodic tables, the discovery of the elements, the elucidation of atomic weights and the discovery of atomic structure (and much, much more).
| Year: 2004 | PT id = 125, Type = data |
Elemental Hydride Types Periodic Table

- Ionic or Salt-Like Hydrides: Molten LiH conducts electricity and hydrogen gas is liberated at the anode confirming presence of hydride ion H. The crystal structures show an ionic lattice, and not an LiH molecular lattice.
- Covalent Hydrides are formed by the p-Bolock elements.
- Metallic or Interstitial Hydrides are formed by many d-block and f-block elements when heated with hydrogen under pressure. The hydrides tend to be non-stoichiometric and they may be of variable composition.
- There is a Hydride Gap where elements do not form hydrides. This roughly maps to the Siderophile Elements of the geologist's periodic table (below).
- The Intermediate Hydrides do not fit: beryllium hydride is polymeric, (BeH2)n. Others have properties between metallic and covalent.
The main group elemental hydrides are all well known reagent chemicals. The main group hydrides always give the lowest and most common oxidation state, and all chemicals are molecular in the gas phase. The Group I and II hydrides are ionic materials, but they can be vaporised to give the molecular form.
The chemicals present and behave as Lewis acids, Lewis bases or Lewis acid/base complexes, here:
By Mark Leach
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| What is the Periodic Table Showing? | Periodicity |
© Mark R. Leach Ph.D. 1999 –
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