krypton

• Description
• General information
• Physical data
• Radii
• Electronegativities
• Solid state structure
• Temperatures
• Enthalpies
• Ionization Enthalpies
• Isotopes
• Further information

Description

Krypton is present in the air at about 1 ppm. The atmosphere of Mars contains a little (about 0.3 ppm) of krypton. It is characterised by its brilliant green and orange spectral lines. The spectral lines of krypton are easily produced and some are very sharp. In 1960 it was internationally agreed that the fundamental unit of length, the metre, should be defined as 1 m = 1,650,763.73 wavelengths (in vacuo) of the orange-red line of Kr-33.

Under normal conditions krypton is colourless, odourless, fairly expensive gas. Solid krypton is a white crystalline substance with a face-centered cubic structure which is common to all the "rare gases". Krypton difluoride, KrF₂, has been prepared in gram quantities and can be made by several methods.

General information

Discoveror: Sir William Ramsay, Morris W. Travers
Date discovered: 1898
Discovered at: Greeat Britain
Meaning of name: From the Greek word "kryptos" meaning "hidden"

Physical data

Standard state: gas at 298 K
Colour: colourless
Density of solid at ambient temperature/kg m^-3: no data
Molar volume/cm³: 27.99

Radii /pm

Atomic: 88
Covalent (single bond):
Pauling radius for the ion [Kr]^-: no data

Valence shell orbital radius maxima (R_max)

orbital	s	p	d	f
radius	72.9	82.9	21.9	no data

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: 3.00
Allred Rochow: 2.94

Crystal Structure

structure: ccp (cubic close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.

Temperatures (/K)

melting point: 115.79
boiling point: 119.93

Enthalpies /kJ mol^-1

fusion: 1.64
vaporization: 9.02

single bond enthalpies:

Kr-F	Kr-Cl	Kr-Br	Kr-I	Kr-Kr
50	no data	no data	no data	5.23

Ionization enthalpies /kJ mol^-1

Number	Enthalpy
1st	1350.7
2nd	2350.3
3rd	3565
4th	5070
5th	6240
6th	7570
7th	10710
8th	12200

Isotopes

This section gives some data for naturally occurring isotopes.

Nominal mass	Accurate mass	% natural abundance
78Kr	77.920396 (9)	0.35 (2)
80Kr	79.916380 (9)	2.25 (2)
82Kr	81.913482 (6)	11.6 (1)
83Kr	82.914135 (4)	11.5 (1)
84Kr	83.911507 (4)	57.0 (3)
86Kr	85.910616 (5)	17.3 (2)

Further Information

• Additional information about WebElements 1.2.2
• This is a licensed copy (here is the full list) of WebElements 1.2.2 and contains a subset of the material contained within the main version of WebElements (version 2)
• For further information please try WebElements version 2
• Sheffield Chemdex: perhaps the largest internet chemistry directory
• Sheffield Chemputer: interactive chemistry calculators on the WWW