Tag Archives: space group

#196 – update

#196 – update


Tomas, one of our readers of this blog, identified an error concerning the space group list project. As he correctly pointed out, the entry of #196 (F23) was wrong as the coordinate set of the solvent free zink  sulfate clearly shows F-43m symmetry (#216).

I have informed the FIZ Karlsruhe and they will delete this wrong entry in their ICSD database with the next update/release.

So, the new (approved) entry for #196 is:
tetrakis((18-Crown-6)-thallium) tetrachloro-manganese bis(tetrachloro-thallium)
Coordination Characteristics of Divalent Tetrahedral (Td and D2d) Tetrahalometalate Anions of 3d Elements and Solid-State 18C6 Reorientations
N.S. Fender, S.S. Finegan, D. Miller. M. Mitchell, I.A. Kahwa, F.R. Fronczek
Inorg. Chem., 1994, 33 (18), pp 4002–4008


MnCl4 tetrahedra (purple)
TlCl4 tetrahedra (blue)


Also the poster of the Space group list project was updated, which you can download here:





This is also an interesting entry because space group #93 is as rarely occupied as space group #89 (P422).

In the paper of Urusov and Nadezhina it is mentioned that according to an investigation of Baur and Kassner in the year 1992 inorganic representatives of this space group are even absent.

Indeed, the ICSD retrieves 0 hits for this space group!

However, there are 6 hits in the CCDC, and for 4 of them also coordinate sets are given.

Example – Tetraphenylarsonium tetrakis(dimethyldithiophosphinato-S,S’)-cerium

Crystal and molecular structures of [AsPh4][Ln(S2PMe2)4] (Ln = Ce or Tm) and their comparison with results obtained from paramagnetic nuclear magnetic resonance data in solution

St.Spiliadis, A.A. Pinkerton, D. Schwarzenbach
J. Chem. Soc., Dalton Trans., 1982, 1809-1813



C (black)
As (purple)
P (orange)
S (yellow)
Ce (lime)

3D rotatable model of [AsPh4][Ln(S2PMe2)4]

[updated] #89



This is one of the most interesting entries in this list, because it is one of the rarest occupied space groups at all. See also the paper by Urusov and Nadezhina about the frequency distribution of space groups in inorganic crystal chemistry:


Currently, the ICSD contains only 2 entries for this space group, namely:

ICSD-74350, (Sr,La)Zn0.5Mn0.5O4

Structural study on new ordered potassium-nickel fluoride-type oxides, strontium lanthanum magnesium manganese oxide and strontium lanthanum zinc manganese oxide

Byeon, S.H.; Kim, I.-S.; Itoh, M.; Nakamura, T.
Materials Research Bulletin (1993) 28, p597-p603


ICSD-94777, (Sr1.5,La0.5)(Cu0.5,Ti0.5)O3.78

Structure and magnetic properties of oxygen pressure induced Sr1.5La0.5Cu0.5Ti0.5O4-d (0.0 <= d <= 0.25)

Byeon, S.H.; Chung, H.
Chemistry of Materials (2002) 14, p556-p561

Interestingly, both datasets were published by the same first author. And, interestingly, both structures were clearly wrongly assigned. A symmetry check of the given coordinate sets revealed that both structures exhibit P4/mmm symmetry.

So, it seems to be the case that there is indeed no single inorganic crystal and no mineral on the earth, which crystallizes in the space group P422.

What about the CCDC, the (metal-)organic world of crystals?

A search retrieves 9 hits. For 6 of them, no coordinates are available. From the three sets with coordinates, two were corrected by the CCDC staff members to be not P422 but P41212 instead.

Accordingly, one compound is left and with good chance it is the only crystal of the world, belonging to the space group P422:

tetrakis(µ2-acetato)-tetrakis(µ2- ferrocenecarboxylato)-tetra-platinum toluene solvate

Interaction of Ferrocene Moieties Across a Square Pt4 Unit: Synthesis, Characterization, and Electrochemical Properties of Carboxylate-Bridged Bimetallic Pt4Fen (n = 2,3, and 4) Complexes

S.Tanaka, K.Mashima
Inorg.Chem. (2011), 50, 11384




3D rotatable model of [Pt4(µ-OCOCH3)4(µ-OCOC5H4FeCp)4]



There might be a second compound, which crystallizes in the space group P422. CrystalWorks (The Chemical Database Service at Daresbury) pointed to their entry:

CrystMet – 458169

M. V. Speka, V. Ya. Markiv, M. I. Zakharenko, N. M. Belyavina
Dopov. Nats. Akad. Nauk. Ukr., ? (2002), 89

Compound: YAl2.6Ga0.4
Cell: 16.67, 16.67, 9.793, 90, 90, 90
Space Group: P422 (89)



Al – lightblue
Ga – purple
Y – orange


Checking the given coordinate set it can be conformed that this is indeed the symmetry of space group P422. Unfortunately, I have no access to the original paper for any additional information.

3D rotatable model of YAl2.6Ga0.4

The Y-Al-Ga ternary systems seem to realize very many and different structures, see for instance:

Isothermal section (400 °C) of the phase diagram of Y–Al–Ga ternary system in the region up to 33.3 at.% Y

M.V Speka, V.Ya Markiv, M.I Zakharenko, N.M Belyavina
Journal of Alloys and Compounds, 348, p138–145




Example – Batisite, Na2BaTi2O2[Si4O12]

Named in allusion to its chemical composition, containing Barium, Titanium, and Silicon.

Crystal structure of batisite

Nikitin A.V., Belov N.V.
Doklady Akademii Nauk SSSR 146 (1962) 1401-1403





BaO10 polyhedra (green)
NaO6/O7 polyhedra (purple)
TiO6 octahedra (blue)
SiO4 tetrahedra (yellow)

3D rotatable model of Batisite




Example – Banalsite, BaNa2Al4Si4O16

Named from a contraction of the component cation symbols: Ba, Na, Al, and Si. It belongs to the group of tectosilicates.

The crystal structure of stronalsite and a redetermination of the structure of banalsite.

Liferovich R P, Locock A J, Mitchell R H, Shpachenko A K
The Canadian Mineralogist 44 (2006) 533-546





BaO10 irregular polyhedra (green)
NaO5 pentagonal pyramids (yellow)
AlO4 tetrahedra (blue)
SiO4 tetrahedra (orange)

3D rotatable model of Banalsite




Example – Edenharterite, PbTlAs3S6

Named in 1992 for Andreas Edenharter (born 1933), Swiss crystal chemist.

Crystal structure of synthetic PbTlAs3S6

T. Balic-Zunic, P. Engel
Zeitschrift für Kristallographie 165 (1983) 261-269




3D rotatable model of Edenharterite