Subject
halide
6
inorganic compound
5
nitrogen
5
phosphorus
5
ammonia
3
biological aspect
3
bromide
3
chalcogenide
3
chloride
3
fluorine
3
iodide
3
nonmetal
3
phosphate
3
selenium
3
silicon
3
sulfide
3
sulfur
3
tellurium
3
allotropy
2
ammonium compound
2
argon
2
atomic model
2
boron
2
carbon
2
carbon dioxide
2
chemical bond
2
fixation
2
fluoride
2
fluorite
2
halogen
2
helium
2
historical aspect
2
hydrazine
2
hydrogen bond
2
inorganic chemistry
2
iodine
2
isotope
2
nitric acid
2
nitrous oxide
2
occurrence
2
organic compound
2
phosphine
2
radiation chemistry
2
rare gas
2
silicate
2
solubility
2
acid
1
adsorption
1
air
1
alloy
1
more ...