The Element Selenium


Selenium is a non metal which is closely related to sulfur and which rarely occurs in nature in its pure elemental form. Biologically, selenium is significant in that it is essential for forming the active centre of enzymes glutathione peroxide and thioredoxin reductase. However, large amounts of selenium are known to be highly toxic while studies show a possible connection between cancer and selenium deficiency.

Selenium is an important substance in the chemical industry that is widely used in various industrial and laboratory syntheses. While the largest use of selenium world wide is in glass and ceramic manufacturing processes, it is also used in photocopying, photocells, light meters and in solar cells.

Atomic Number & Chemical Properties


Element Basics:

Chemical Symbol: Se
Atomic Number: 34
Atomic Weight: 78.96
Element Classification: Non-Metal
Discovered By: Jons Jacob Berzelius
Date of Discovery: 1818 (Sweden)
Origin of Name: Greek: selene (moon).

How to Recognize it at a Party:

A soft metalloid similar to sulfur

Seriously Atomic Information:

Density (g/cc): 4.79
Melting Point (°K): 490
Boiling Point (°K): 958.1
Atomic Radius (pm): 140
Atomic Volume (cc/mol): 16.5
Covalent Radius (pm): 116
Ionic Radius: 42 (+6e) 191 (-2e)
Pauling Negativity Number: 2.55
First Ionizing Energy (kJ/mol): 940.4
Oxidation States: 6, 4, -2
Electronic Configuration: [Ar] 3d10 4s2 4p4

Getting Intimate with Selenium:

Lattice Structure: Hexagonal (HEX)
Lattice Constant (Å): 4.360
Lattice C/A Ratio: n/a
Specific Heat (@20°C J/g mol): 0.321 (Se-Se)
Fusion Heat (kJ/mol): 5.23
Evaporation Heat (kJ/mol): 59.7
Thermal Conductivity (@25°C W/m K):
Debye Temperature (°K): n/a


Society's Questions About Selenium:

Have you ever wondered what everyone else in the world thinks about Selenium? Is anyone else looking for it too? If so, why? What do they want?

The following list shows the most common online questions about the element Selenium. Are your questions the same or different from everyone else's?

Top Selenium Topics:

  • selenium 966
  • element selenium 61
  • facts about selenium 61
  • benefits of selenium 45
  • selenium sulfide hair loss 45
  • what is selenium used for 40
  • selenium poisoning 33
  • selenium sulfide irritation 33
  • how is selenium ii sulphide found 28
  • selenium sulfide side effect 26
  • history of selenium 24
  • selenium and breast cancer 22
  • selenium deficiency 22
  • selenium element 22
  • what is selenium 21
  • chemical properties of selenium 19
  • selenium methionine 17
  • selenium sulfide 17
  • selenium sperm 15
  • selenium yeast 15
  • determination of selenium using graphite furnace 14
  • selenium glass lense 14
  • selenium price 14
  • selenium side effects 14
  • selenium toxicity 14
  • physical properties of selenium 12
  • selenium menopause abstract 12
  • selenium speakers 12
  • selenium st324 12
  • topamax zinc and selenium for hair loss 12
  • who discovered selenium 12
  • foods high in selenium 10
  • how is selenium sulphide found in nature 10
  • is selenium a metal or a nonmetal 10
  • n zimes pain management selenium triadhealth care com 10
  • selenium and low blood sugar 10
  • selenium drum 10
  • selenium hardness 10
  • selenium open source 10
  • selenium open source getting started 10
  • suggested selenium and vitamin e for prostate cancer 10
  • uses of selenium 10
  • safety and efficacy of selenium breast cancer 8
  • selenium and thyroid resistance 8
  • selenium and tyroiditis 8
  • selenium brazil nuts 8
  • selenium brings on diabetes 8
  • selenium overdose 8
  • selenium rectifier replace with silicon 8
  • selenium sources 8
  • side effects of selenium 8
  • use of selenium 8
  • what does selenium look like 8
  • freezing point of selenium 7
  • how did selenium get its name 7
  • images of selenium 7
  • ions formed selenium 7
  • liquid selenium 7
  • safe levels of selenium 7
  • selenium 3v1k2-7k/650 7
  • selenium abdominal fat 7
  • selenium asthenia abstract 7
  • selenium atomic diagram 7
  • selenium effect on kidneys 7
  • selenium glycinate 7
  • selenium metal prices 7
  • selenium mineral 7
  • selenium poisoning causing blindness and herbal solution 7
  • selenium rectifier 7
  • selenium rich foods 7
  • selenium skin problems 7
  • selenium sulfide shampoo 7
  • selenium texture 7
  • veterinary, selenium 7
  • what elements does selenium bond with 7
  • benifits of using selenium 5
  • canola meal selenium content 5
  • daily dossage for selenium 5
  • determining selenium in garlic by graphite furnace 5
  • doll selenia arthur and the invisibles 5
  • early uses of selenium 5
  • fish life history fin mineral micronutrient carbon selenium 5
  • foods with zinc and selenium 5
  • hologic selenia 5
  • how selenium enters marshes 5
  • how substance freezes selenium 5
  • how to determine selenium using graphite furnace 5
  • human cardiomyopathy selenium yeast 5
  • lewis structure of selenium chloride 5
  • lorad selenia 5
  • new uses of element selenium 5
  • oat hay and selenium deficiency 5
  • selenium + cancer 5
  • selenium adverse events 5
  • selenium and agile and resume and majobs 5
  • selenium and legumes 5
  • selenium cancer prevention 5
  • selenium cells 5
  • selenium d250 5
  • selenium deficiencies 5