Helium

Probable observation of a supersolid helium phase

Abstract: When liquid 4He is cooled below 2.176 K, it undergoes a phase transition—Bose–Einstein condensation—and becomes a super- fluid with zero viscosity. Once in such a state, it can flow without dissipation even through pores of atomic dimensions. Although it is intuitive to associate superflow only with the liquid phase, it has been proposed theoretically that superflow can also occur in the solid phase of 4He. Owing to quantum mechanical fluctuations, delocalized vacancies and defects are expected to be present in crystalline solid 4He, even in the limit of zero temperature. These zero-point vacancies can in principle allow the appearance of superfluidity in the solid. However, in spite of many attempts, such a 'supersolid' phase has yet to be observed in bulk solid 4He. Here we report torsional oscillator measurements on solid helium confined in a porous medium, a configuration that is likely to be more heavily populated with vacancies than bulk helium. We find an abrupt drop in the rotational inertia5 of the confined solid below a certain critical temperature. The most likely interpretation of the inertia drop is entry into the supersolid phase. If confirmed, our results show that all three states of matter—gas, liquid and solid—can undergo Bose–Einstein condensation.

Probable observation of a supersolid helium phase, Kim, E., and Chan M. H. W. , Nature, 1/2004, Volume 427, Issue 6971, p.225 - 227, (2004)

List of elements by atomic number

Here is a list of the elements sorted by atomic number.

Janet periodic table

The Janet periodic table

The Janet periodic table is an excellent alternative periodic table and organises elements according to orbital filling. Therefore, hydrogen is above lithium on the grounds they are both ns1, and helium above beryllium on the grounds they are both ns2. Current Group numbers are displayed to help orientation with the standard table.

Element nameElement symbolAtomic number
HydrogenH1
HeliumHe2
LithiumLi3
The JANET periodic table.
Group   3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1 2
Period
1 1
H
2
He
1 3
Li
4
Be
2 5
B
6
C
7
N
8
O
9
F
10
Ne
11
Na
12
Mg
3 13
Al
14
Si
15
P
16
S
17
Cl
18
Ar
19
K
20
Ca
4 21
Sc
22
Ti
23
V
24
Cr
25
Mn
26
Fe
27
Co
28
Ni
29
Cu
30
Zn
31
Ga
32
Ge
33
As
34
Se
35
Br
36
Kr
37
Rb
38
Sr
5 39
Y
40
Zr
41
Nb
42
Mo
43
Tc
44
Ru
45
Rh
46
Pd
47
Ag
48
Cd
49
In
50
Sn
51
Sb
52
Te
53
I
54
Xe
55
Cs
56
Ba
6 57
La
58
Ce
59
Pr
60
Nd
61
Pm
62
Sm
63
Eu
64
Gd
65
Tb
66
Dy
67
Ho
68
Er
69
Tm
70
Yb
71
Lu
72
Hf
73
Ta
74
W
75
Re
76
Os
77
Ir
78
Pt
79
Au
80
Hg
81
Tl
82
Pb
83
Bi
84
Po
85
At
86
Rn
87
Fr
88
Ra
7 89
Ac
90
Th
91
Pa
92
U
93
Np
94
Pu
95
Am
96
Cm
97
Bk
98
Cf
99
Es
100
Fm
101
Md
102
No
103
Lr
104
Rf
105
Db
106
Sg
107
Bh
108
Hs
109
Mt
110
Ds
111
Rg
112
Cp
113
Uut
114
Uuq
115
Uup
116
Uuh
117
Uus
118
Uuo
119
Uue
120
Ubn

List of elements sorted by symbol

Here is a list of the elements sorted by element symbol.
Element nameElement symbolAtomic number
ActiniumAc89
SilverAg47
Aluminium (aluminum)Al13
AmericiumAm95
ArgonAr18
ArsenicAs33
AstatineAt85
GoldAu79
BoronB5
BariumBa56
BerylliumBe4
BohriumBh107
BismuthBi83
BerkeliumBk97
BromineBr35
CarbonC6
CalciumCa20
CadmiumCd48
CeriumCe58
CaliforniumCf98
ChlorineCl17
CuriumCm96
CobaltCo27
CoperniciumCp112
ChromiumCr24
Caesium (Cesium)Cs55
CopperCu29
DubniumDb105
DarmstadtiumDs110
DysprosiumDy66
ErbiumEr68
EinsteiniumEs99
EuropiumEu63
FluorineF9
IronFe26
FermiumFm100
FranciumFr87
GalliumGa31
GadoliniumGd64
GermaniumGe32
HydrogenH1
HeliumHe2
HafniumHf72
MercuryHg80
HolmiumHo67
HassiumHs108
IodineI53
IndiumIn49
IridiumIr77
PotassiumK19
KryptonKr36
LanthanumLa57
LithiumLi3
LawrenciumLr103
LutetiumLu71
MendeleviumMd101
MagnesiumMg12
ManganeseMn25
MolybdenumMo42
MeitneriumMt109
NitrogenN7
SodiumNa11
NiobiumNb41
NeodymiumNd60
NeonNe10
NickelNi28
NobeliumNo102
NeptuniumNp93
OxygenO8
OsmiumOs76
PhosphorusP15
ProtactiniumPa91
LeadPb82
PalladiumPd46
PromethiumPm61
PoloniumPo84
PraseodymiumPr59
PlatinumPt78
PlutoniumPu94
RadiumRa88
RubidiumRb37
RheniumRe75
RutherfordiumRf104
RoentgeniumRg111
RhodiumRh45
RadonRn86
RutheniumRu44
Sulfur (Sulphur)S16
AntimonySb51
ScandiumSc21
SeleniumSe34
SeaborgiumSg106
SiliconSi14
SamariumSm62
TinSn50
StrontiumSr38
TantalumTa73
TerbiumTb65
TechnetiumTc43
TelluriumTe52
ThoriumTh90
TitaniumTi22
ThalliumTl81
ThuliumTm69
UraniumU92
UnunhexiumUuh116
UnunoctiumUuo118
UnunpentiumUup115
UnunquadiumUuq114
UnunseptiumUus117
UnuntriumUut113
VanadiumV23
TungstenW74
XenonXe54
YttriumY39
YtterbiumYb70
ZincZn30
ZirconiumZr40

List of elements sorted by name

Here is a list of the elements sorted by alphabetically by element name.

Element name Element symbol Atomic number
Actinium Ac 89
Aluminium (aluminum) Al 13
Americium Am 95
Antimony Sb 51
Argon Ar 18
Arsenic As 33
Astatine At 85
Barium Ba 56
Berkelium Bk 97
Beryllium Be 4
Bismuth Bi 83
Bohrium Bh 107
Boron B 5
Bromine Br 35
Cadmium Cd 48
Caesium (Cesium) Cs 55
Calcium Ca 20
Californium Cf 98
Carbon C 6
Cerium Ce 58
Chlorine Cl 17
Chromium Cr 24
Cobalt Co 27
Copernicium Cp 112
Copper Cu 29
Curium Cm 96
Darmstadtium Ds 110
Dubnium Db 105
Dysprosium Dy 66
Einsteinium Es 99
Erbium Er 68
Europium Eu 63
Fermium Fm 100
Fluorine F 9
Francium Fr 87
Gadolinium Gd 64
Gallium Ga 31
Germanium Ge 32
Gold Au 79
Hafnium Hf 72
Hassium Hs 108
Helium He 2
Holmium Ho 67
Hydrogen H 1
Indium In 49
Iodine I 53
Iridium Ir 77
Iron Fe 26
Krypton Kr 36
Lanthanum La 57
Lawrencium Lr 103
Lead Pb 82
Lithium Li 3
Lutetium Lu 71
Magnesium Mg 12
Manganese Mn 25
Meitnerium Mt 109
Mendelevium Md 101
Mercury Hg 80
Molybdenum Mo 42
Neodymium Nd 60
Neon Ne 10
Neptunium Np 93
Nickel Ni 28
Niobium Nb 41
Nitrogen N 7
Nobelium No 102
Osmium Os 76
Oxygen O 8
Palladium Pd 46
Phosphorus P 15
Platinum Pt 78
Plutonium Pu 94
Polonium Po 84
Potassium K 19
Praseodymium Pr 59
Promethium Pm 61
Protactinium Pa 91
Radium Ra 88
Radon Rn 86
Rhenium Re 75
Rhodium Rh 45
Roentgenium Rg 111
Rubidium Rb 37
Ruthenium Ru 44
Rutherfordium Rf 104
Samarium Sm 62
Scandium Sc 21
Seaborgium Sg 106
Selenium Se 34
Silicon Si 14
Silver Ag 47
Sodium Na 11
Strontium Sr 38
Sulfur (Sulphur) S 16
Tantalum Ta 73
Technetium Tc 43
Tellurium Te 52
Terbium Tb 65
Thallium Tl 81
Thorium Th 90
Thulium Tm 69
Tin Sn 50
Titanium Ti 22
Tungsten W 74
Ununhexium Uuh 116
Ununoctium Uuo 118
Ununpentium Uup 115
Ununquadium Uuq 114
Ununseptium Uus 117
Ununtrium Uut 113
Uranium U 92
Vanadium V 23
Xenon Xe 54
Ytterbium Yb 70
Yttrium Y 39
Zinc Zn 30
Zirconium Zr 40

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Table 1. Table of element "popularities" relative to hydrogen = 100
ElementPopularityElementPopularityElementPopularity
actiniumholmiumrhodium
aluminium hydrogen rubidium
americium indium ruthenium
antimony iodine rutherfordium
argon iridium samarium
arsenic iron scandium
astatine krypton seaborgium
barium lanthanum selenium
berkelium lawrencium silicon
beryllium lead silver
bismuth lithium sodium
bohrium lutetium strontium
boron magnesium sulphur
bromine manganese tantalum
cadmium meitnerium technetium
caesium mendelevium tellurium
calcium mercury terbium
californium molybdenum thallium
carbon neodymium thorium
cerium neon thulium
chlorine neptunium tin
chromium nickel titanium
cobalt niobium tungsten
copper nitrogen ununbium
curium nobelium ununhexium
dubnium osmium ununnilium
dysprosium oxygen ununoctium
einsteinium palladium ununpentium
erbium phosphorus ununquadium
europium platinum ununseptium
fermium plutonium ununtrium
fluorine polonium roentgenium
francium potassium uranium
gadolinium praseodymium vanadium
gallium promethium xenon
germanium protactinium ytterbium
gold radium yttrium
hafnium radon zinc
hassium rhenium zirconium
helium    

Periodic Tales on Radio 4

The BBC is airing some "periodic tales" on Radio 4. Familiar Radio 4 voices introduce elements from the Periodic Table and the unique roles they play in human existence - with a little help from the irreverent Tom Lehrer. Listen to these ten elements:

  • Krypton: Heidli Nicklaus on the Superman element, krypton
  • Helium: Brian Perkins dramatises the effects of Helium
  • Silver: Trevor Harrison (Eddie Grundy in the Archers) finds some unusual properties of Silver
  • Cobalt: Hedli Nicklaus (Cathy Perks) takes on the goblin element of cobalt
  • Selenium: Carole Boyd (The Archers' Linda Snell) unearths selenium
  • Oxygen: Brian Perkins bravely dramatises the effects of oxygen
  • Arsenic: Charlotte Green takes on the deadly history of arsenic
  • Mercury: Carole Boyd (Linda Snell) reflects on mercury, the poisonous liquid metal
  • Iodine: Charlotte Green on the discovery of iodine's essential place in brain development
  • Nickel: Trevor Harrison reveals that the space station Mir is largely made of nickel

[[Note added Dec 2009: sadly these recordings no longer exist on the BBC site. I did offer to host them here but no luck]]

Helium supersolids?


In a letter to Nature E. Kim and M. H. W. Chan (Pennsylvania State University, USA) note that when liquid 4He is cooled below 2.176 K, it undergoes a phase transition and becomes a superfluid with zero viscosity. They claim that in addition to superflow in the liquid phase, superflow can also occur under some conditions in the solid phase of one of the helium isotopes (4He), and present results to back this up. In other words - evidence for a "supersolid". A supersolid behaves like a superfluid (flows without resistance) although it has crystalline solid characteristics.1

Buckyballs clue to mass extinction 250 million years ago

Earth's most severe mass extinction - an event 250 million years ago that wiped out 90 percent of all marine species and 70 percent of land vertebrates - was triggered by a collision with a comet or asteroid, according to a team led by The University of Washington, Seattle, USA. Evidence is based upon elegant findings involving carbon molecules called buckminsterfullerenes (C60, Buckyballs) with the gases helium and argon trapped inside their cage structures.

The scientists do not know the site of the impact 250 million years ago, when all Earth's land formed a supercontinent called Pangea. However, the space body left a calling card - a much higher level of complex carbon molecules called buckminsterfullerenes, or Buckyballs, with the noble (or chemically nonreactive) gases helium and argon trapped inside their cage structures. Fullerenes, which contain 60 or more carbon atoms and have a structure resembling a soccer ball or a geodesic dome, are named for Buckminster Fuller, who invented the geodesic dome.

The researchers know these particular Buckyballs are extraterrestrial because the noble gases trapped inside have an unusual ratio of isotopes. For instance, terrestrial helium is mostly helium-4 and contains only a small amount of helium-3, while extraterrestrial helium - the kind found in these fullerenes - is mostly helium-3.

"These things form in carbon stars. That's what's exciting about finding fullerenes as a tracer," according to Luann Becker, one of scientific team involved. The extreme temperatures and gas pressures in carbon stars are perhaps the only way extraterrestrial noble gases could be forced inside a fullerene, she said. These gas-laden fullerenes were formed outside the Solar System, and their concentration at the Permian-Triassic boundary means they were delivered by a comet or asteroid.

WebElements: the periodic table on the WWW [http://www.webelements.com/]

Copyright 1993-2011 Mark Winter [The University of Sheffield and WebElements Ltd, UK]. All rights reserved.