iucr

commissions

principles
aperiodic crystals
biological macromolecules
quantum crystallography
crystal growth and characterization of materials
crystallographic computing
crystallographic nomenclature
crystallographic teaching
crystallography in art and cultural heritage
crystallography of materials
electron crystallography
high pressure
inorganic and mineral structures
international tables
journals
magnetic structures
mathematical and theoretical crystallography
neutron scattering
nmr crystallography
powder diffraction
small-angle scattering
structural chemistry
synchrotron and xfel radiation
xafs

congress

2020 iucr xxv
2017 iucr xxiv
2014 iucr xxiii
2011 iucr xxii
2008 iucr xxi
2005 iucr xx
2002 iucr xix
1999 iucr xviii
1996 iucr xvii
1993 iucr xvi
1990 iucr xv
1987 iucr xiv
1984 iucr xiii
1981 iucr xii
1978 iucr xi
1975 iucr x
1972 iucr ix
1969 iucr viii
1966 iucr vii
1963 iucr vi
1960 iucr v
1957 iucr iv
1954 iucr iii
1951 iucr ii
1948 iucr i

people

nobel prize

all
agre
anfinsen
barkla
boyer
w.h.bragg
w.l.bragg
brockhouse
de broglie
charpak
crick
curl
davisson
debye
deisenhofer
geim
de gennes
hauptman
hodgkin
huber
karle
karplus
kendrew
klug
kobilka
kornberg
kroto
laue
lefkowitz
levitt
lipscomb
mackinnon
michel
novoselov
pauling
perutz
ramakrishnan
roentgen
shechtman
shull
skou
smalley
steitz
sumner
thomson
walker
warshel
watson
wilkins
yonath

resources

commissions

aperiodic crystals
biological macromolecules
quantum crystallography
crystal growth and characterization of materials
crystallographic computing
crystallographic nomenclature
crystallographic teaching
crystallography in art and cultural heritage
crystallography of materials
electron crystallography
high pressure
inorganic and mineral structures
international tables
journals
magnetic structures
mathematical and theoretical crystallography
neutron scattering
NMR crystallography
powder diffraction
small-angle scattering
structural chemistry
synchrotron radiation
xafs

outreach

openlabs

calendar
OpenLab Costa Rica
IUCr-IUPAP-ICTP OpenLab Senegal
Bruker OpenLab Cameroon
Rigaku OpenLab Bolivia
Bruker OpenLab Albania
Bruker OpenLab Uruguay 2
Rigaku OpenLab Cambodia 2
Bruker OpenLab Vietnam 2
Bruker OpenLab Senegal
PANalytical OpenLab Mexico 2
CCDC OpenLab Kenya
Bruker OpenLab Tunisia
Bruker OpenLab Algeria
PANalytical OpenLab Turkey
Bruker OpenLab Vietnam
Agilent OpenLab Hong Kong
PANalytical OpenLab Mexico
Rigaku OpenLab Colombia
grenoble-darmstadt
Agilent OpenLab Turkey
Bruker OpenLab Indonesia
Bruker OpenLab Uruguay
Rigaku OpenLab Cambodia
PANalytical OpenLab Ghana
Bruker OpenLab Morocco
Agilent OpenLab Argentina
Bruker OpenLab Pakistan

The following short quiz will test your knowledge and understanding of the Bravais lattice.

(1) What are the Bravais-lattice symbols of the following space groups: No. 2, No. 40, No. 150 and No. 161?

(2) What is the essential geometric difference between the Bravais-lattice types *mP* and *mS*? Note: The correct answer contains neither the words 'affine equivalent' nor the words 'unit cell'. Try also the Bravais-lattice types *oP*, *oS*, *oF* and *oI*.

The 14 Bravais-lattice types are at the very heart of crystallography. It is somewhat remarkable that, in the second decade of the 21st Century, we may still learn new things about them. In Grimmer's paper [Grimmer, H. (2015). *Acta Cryst*. A**71**, doi:10.1107/S2053273314027351] he does just this and provides important new insights. Grimmer presents an entirely original way of determining the hierarchical arrangement of Bravais-lattice types. The result is summarised in an easily understood figure. In the figure, the Bravais-lattice type at the upper end of a line is a special case of the type at its lower end. Grimmer's approach to determining the hierarchy is to examine the group-subgroup relations amongst the space groups of the Bravais-lattice types. The latter are those (14) symmorphic space groups with the point group of a holohedry.

[Flack, H.D. (2015). *Acta Cryst*. A**71**, doi:10.1107/S2053273315002557]

The International Union of Crystallography is a non-profit scientific union serving the world-wide interests of crystallographers and other scientists employing crystallographic methods.

© International Union of Crystallography