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![The crystal structure of hemimorphite. (a) Here, two zinc and one silicon tetrahedra comprise three-membered ring in (010) plane; (b) the structure of hemimorphite projected onto the a-b plane. Six-membered rings and eight-membered rings are in the a-b plane. Large cavities run along the c axis and contain H2O. The corrugated layers of three-membered rings are also apparent in this projection (modified from Hill, et al., 1977 [8]).](publication/341305179/figure/fig1/AS:890182890975232@1589247548533/The-crystal-structure-of-hemimorphite-a-Here-two-zinc-and-one-silicon-tetrahedra.png)
The crystal structure of hemimorphite. (a) Here, two zinc and one silicon tetrahedra comprise three-membered ring in (010) plane; (b) the structure of hemimorphite projected onto the a-b plane. Six-membered rings and eight-membered rings are in the a-b plane. Large cavities run along the c axis and contain H2O. The corrugated layers of three-membered rings are also apparent in this projection (modified from Hill, et al., 1977 [8]).
Source publication
Hemimorphite, with the chemical formula Zn4Si2O7(OH)2·H2O, contains two different types of structurally bound hydrogen: molecular water and hydroxyl. The elastic properties of single-crystal hemimorphite have been determined by Brillouin spectroscopy at ambient conditions, yielding tight constraints on all nine single-crystal elastic moduli (Cij)....
Contexts in source publication
Context 1
... structure of orthorhombic hemimorphite, with space group Imm2, is composed of a three-dimensional framework, in which two ZnO 3 (OH) tetrahedra and one SiO 4 tetrahedron form three-membered rings that are corner-shared to form corrugated sheets parallel to (010) [8,9] (Figure 1). SiO 4 tetrahedra in one layer are linked to SiO 4 tetrahedra in an adjacent layer, while the ZnO 3 (OH) tetrahedra in adjacent layers also only link to each other, completing the framework. ...
Context 2
... structure of orthorhombic hemimorphite, with space group Imm2, is composed of a threedimensional framework, in which two ZnO3(OH) tetrahedra and one SiO4 tetrahedron form threemembered rings that are corner-shared to form corrugated sheets parallel to (010) [8,9] (Figure 1). SiO4 tetrahedra in one layer are linked to SiO4 tetrahedra in an adjacent layer, while the ZnO3(OH) tetrahedra in adjacent layers also only link to each other, completing the framework. ...
Citations
The new mineral khurayyimite Ca7Zn4(Si2O7)2(OH)10·4H2O occurs in colorless spherulitic aggregates in small cavities of altered spurrite marbles located in the northern part of the Siwaqa pyrometamorphic rock area, Central Jordan. It is a low-temperature, hydrothermal mineral and is formed at a temperature lower than 100 °C. Synchrotron single-crystal X-ray diffraction experiments have revealed that khurayyimite crystallizes in space group P21/c, with unit cell parameters a = 11.2171(8), b = 9.0897(5), c = 14.0451(10) Å, β = 113.297(8)º, V = 1315.28(17) Å3 and Z = 2. The crystal structure of khurayyimite exhibits tetrahedral chains of periodicity 6. The sequence of SiO4 and ZnO2(OH)2-tetrahedra along the chain is Si-Si-Zn. The neighboring SiO4-tetrahedra of the corrugated chains are bridged by additional ZnO2 (OH)2-tetrahedra to form 3-connected dreier rings. The chains can be addressed as loop-branched sechser single chains {lB, 1 1 ∞ }[ 6Zn4Si4O21 ]. The chains are linked by clusters of five CaO6 and two CaO7 polyhedra with additional OH groups and H2O molecules in the coordination environment. Based on the connectedness and one-dimensional polymerisations of tetrahedra (TO4)n− , chains of khurayyimite belong to the same group as vlasovite Na2ZrSi4O11 , since they can be described with geometrical repeat unit cTr = 2T43T4 and topological repeat unit cVr = 2V23V2 .
