|Halogens are aggressive and dangerous gases or solids (iodine, I) that react with almost anything. Fluorine (F) is probably the element that forms the most compounds - even with some noble gases.|
|Fluorine is of immense importance in technology:
without hydrofluoric acid (HF) there would be no semiconductor industry. Even
exotic compounds like tungsten-hexa- fluoride (WF6) are of
Fluoride or fluorspar (CaF2) is the naturally occurring mineral for making fluorine but it is also used as "flux" in smelting metals.
|Chlorine (Cl) is not only part of
rock salt (NaCl) but one of the most important basic ingredients of chemistry,
e.g. as hydrofluoric acid (HCl).
Bromine (Br) and iodine (I) are know from medical applications but are not all that important anymore, Not so long ago, photography used "film" and for that you needed light sensitive chemicals containing those elements
Astate is radioactive, does not occur in nature and thus of no interest.
|Table of Basic Data|
|In case of doubt all numbers are for room temperatures|
cubic; lattice const. = a
bcc = body centered cubic
sc = simple cubic
hp = simple hexagonal
hcp = hexagonal close packed; lattice constants a and c.
op = simple orthorhombic, monoclinic, triclinic
tp = simple tetragonal
dia = diamond structure
r = trigonal or rhomboedral trigonal
Periodic Table of the Elements
Group 18 / VII; Noble Gases
Bravais Lattices and Crystals
Diamond, and other Carbon Specialities
Lattice and Crystal
Units and Constants
© H. Föll (Iron, Steel and Swords script)