|name, symbol, ordinal number||potassium, K, 19|
|series||of alkali metals|
|group, Period, block||1 (IA), 4, s|
|proportion at the Earth's shell||2.4%|
|atomic radius (computed)||220 (243) pm|
|Kovalenter radius||196 pm|
|van the Waals radius||275 pm|
|Elektronenkonfiguration||[acre] 4s 1|
|Electrons per energy level||2, 8, 8, 1|
|electron affinity||2.3 eV|
|1. Ionization energy||418.8 kJ/mol|
|2. Ionization energy||3052 kJ/mol|
|3. Ionization energy||4420 kJ/mol|
|4. Ionization energy||5877 kJ/mol|
|5. Ionization energy||7975 kJ/mol|
|6. Ionization energy||9590 kJ/mol|
|7. Ionization energy||11343 kJ/mol|
|8. Ionization energy||14944 kJ/mol|
|9. Ionization energy||16963.7 kJ/mol|
|10. Ionization energy||48610 kJ/mol|
|state of aggregation||firmly|
|crystal structure||cubically body-centered|
|density (Mohshärte)||856 kg/m 3 (0,4)|
|melting point||336.53 K (63.38 ° C)|
|boiling point||1032 K (759 °C)|
|Molecular volume||45,94 · 10 -6 m 3 /mol|
|heat of vaporization||79.87 kJ/mol|
|heat of fusion||2.334 kJ/mol|
|steam pressure||1,06 · 10 -4 Pa with _ _ K|
|speed of sound||2000 m/s with 293,15 K|
|specific thermal capacity||757 j (kg · K)|
|Electrical conductivity||13,9 ·10 6 S /m|
|heat conductivity||102.4 w (m · K)|
|hydrides and oxides (basicity)||K 2 O (strongly basic)|
|normal potential||-2.92 V (K + + e - → K)|
|Elektronegativität||of 0.82 (Pauling scale)|
| as far as possible and common, become SI-UNITs uses.|
If not differently notes,
the indicated data apply with standard conditions.
Table of contents
to 19. November 1807 reported Davy,he succeeded in winning by electrolysis of weakly dampened corroding alkalis two different metals; it called the metal Sodium (this is this very day the French and English name for sodium), because it is contained in soda, thatother Potassium (= English and French name for potassium), because one can win it from potash. In the German language area the Sodium Davys is designated since 1811 after a suggestion of Berzelius as sodium, during one for the Potassium Davys thatof Klaproth 1796 imported expression potassium (of arab.: aluminium-qali = ash, from plant ash profitable) took over.
Naturally occurring kaliumhaltige minerals are:
- Sylvin - KCl
- Sylvinit - KCl * NaCl
- Carnallit - KCl * MgCl 2 * 6 H 2 O
- dock rivet - KCl * MgSO 4 * 3 H 2 O
- Schönit - K2 SO 4 * MgSO 4 * 6 H 2 O
- Polyhalit - K 2 SO 4 * MgSO 4 * MgSO 4 * 2 CaSO 4
- Orthoklas (Kalifeldspat) - K [AlSi 3 O 8]
- Muskovit (potash mica) - KAl 2(OH, F) 2 [AlSi 3 O 10]
similar to the other alkali metals potassium reacts with other elements and connections very violently and occurs in the natural environment only in bound form. Chemically it is more reactiveas sodium. Potassium reacts violently with water under formation of potassium hydroxide and release of hydrogen. With Luftzutritt the hydrogen, it catches fire can thereby to Verpuffungen and explosions come. In dry oxygen it burns under violet flame too Potassium hyperoxide KO 2. At damp air it continues to react with water and carbon dioxide to potassium carbonate. In liquid ammonia potassium, like all alkali metals, is well soluble under education of a blue-violet solution. With the halogens bromine and iodine sit downPotassium under detonation to the appropriate halides over.
The disposal of potassium is done via careful bringing in of small pieces of the metal in a large surplus of third Butanol, in which it dissolves under formation of the alcoholate.
At air becomes encrustedthe silver-white shining plane of section of the fresh metal within seconds with a bluish resplendent oxide coating. Metallic potassium is therefore kept under inert gas or paraffin oil. Contrary to sodium potassium knows crusts from oxides, peroxides and hydroxides with longer storage neverthelessform, which can cover the metal in form of reddish-yellow layers and explode those with contact or pressure. A safe disposal is then no longer possible, here offers itself only the burn-up of the complete bundle under controlled conditions.
Potassiumin the nutrition
in g/kg and 87% T
Grass products 25-35g
lactose molasses 35g
field beans 11g
RWS cake 14g
potassium becomes mainly in fast breeders in forma NAK alloy as coolant assigned. Otherwise metallic potassium has only small technical meaning, since it can be replaced by the cheaper sodium.
- Doping from tungsten wires to the production of lamp spirals
- NAK heat alloy (see sodium)
- potassium air cleaner ( potash cartridges) among other things upSubmarines for air filtering in the employment
meaning as fertilizer
Important kaliumhaltige fertilizers:
meaning for the body
potassium is an essential mineral material, the daily need of humans lies with approximately 2 G. Potassium realms food are among other things Mushrooms, bananas, beans, Chilies, cheese, spinach and potatoes, init with up to 5 g Kalium/100 g food seems to those.
In the body potassium plays an outstanding role with the regularization of the diaphragm potential. The intrazelluläre potassium concentration is with approximately 150 mmol/l, is extracellular to 4 mmol/l. The concentration on Sodium lies intrazellulär with approx. 10 mmol/l, extracellularly with 140 mmol/l. These concentration differences are received by the Na/K ATPase upright and are vital for the function of the cell. Durable shifting of these cellular concentrations can with more increased (Hyperkaliämie) ormore degraded (Hypokaliämie) arise to blood potassium concentration and leads to disease symptoms, which can be life-threatening. The poison syringe used in the USA to executions contains Kaliumchlorid, which leads to a paralysis of the heart musculature and thus to death. Potassium belongs to thatmost important electrolytes of the body fluid and is for the controlling of the muscle activity with responsible. With high speed sportsmen it can come by excessive Ausschwitzen from potassium to cramps and exhaustion conditions.
potassium consists to 0.012% of the radioactive isotope 40K and causes nearly 10% for the natural radioactive load of a Federal citizen (0.17 mSv /a to 2.1 mSv/a <ref>Federal Office for radiation protection< /ref>.
one knows proof
of potassium apart from the spectroscopic proof in water loosened potassium - ionsprove with ion-selective electrodes. Most potassium electrodes use the specific integration of potassium by Valinomycin C 54 H 90 N 6 O 18, which are embedded in a concentration of approximately 0.7% into a plastic diaphragm.
In addition is thatqualitative potassium proof by means of perchloric acid mögich. It forms its Kaliumperchlorat, a white precipitation.
Potassium can quantitative be determined with the help of gravimetry. Here potassium weighed out as Tetraphenylborat pleases and the received precipitation.
in its connectionspotassium seems only as 1-wertiges to cation:
- Potassium bromide
- potassium carbonate (potash)
- potassium chlorate
- potassium cyanide
- potassium fluoride
- potassium hydraulic gene phosphate
- potassium hydroxide
- potassium hyperoxide
- potassium sodium tender advice (Seignette salt)
- potassium permanganate
- potassium polysulfide
- potassium sulfate
- Kaliumhexacyanoferrat (III)
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