... coordination), bordered by two B cations (dodecahedral) at the ribbon edges ( Fig. 6 ). Pairs of Si-tetrahedra ( T ) flank the ribbon on both sides and their number is considered for the I beam notation of each species: 2 for amphibole; 3 for clinojimthompsonite; and 2 combined with 3 for chesterite...

... sheets alternating with a layer of Cl - anions in a 2:1 ratio. The incorporation of high-charge cations (V 5+ , Mo 6+ , As 5+ , Si 4+ ) into the litharge sheet involves the formation of square cavities where MoO 5 square pyramids and (Si,As,V)O 4 tetrahedra are hosted. On the basis of information gained...

... by Zn(1)-centered tetrahedra, two independent Ca(1)- and Ca(2)-centered polyhedra, and CO 3 groups. Heteropolyhedral Ca-Zn-CO 3 {001} layers occur in paulišite and are connected along c through CO 3 groups and Ca(2)-centered polyhedra, as well as H-bonds. Along with minrecordite, skorpionite...

.../ ). Figure 1. Crystal structure of ussingite from neutron diffraction ( Williams and Weller 2012 ). Blue and gray tetrahedra represent SiO 4 and AlO 4 tetrahedra, respectively. Red and pink spheres represent O and H atoms, respectively. The black box delineates the unit-cell dimension. The four...

... by SO 4 tetrahedra along the b axis and by the oxalate groups (C 2 O 4 ) 2− along the a axis to form sheets parallel to (001). Between the sheets are layers of M 2+ (H 2 O) 6 octahedra ( M = Zn 2+ , Mg 2+ , Fe 2+ , and Mn 2+ ) and three symmetrically distinct H 2 O molecules that are not bonded to any...

...) Å 3 , Z = 2. The structures of boojumite ( R 1 = 0.057 for 1538 I > 2σ I ) and kennygayite ( R 1 = 0.046 for 2419 I > 2σ I ) are both based on chains of edge-sharing oxocentered OPb 4 tetrahedra. The chain in boojumite is sinuous, whereas that in kennygayite is zig-zag. Fig. 4. A crystal...

... (e.g., Dera et al. 2013a ). As a result, the c (the extending direction of the tetrahedra chains) is decreased much more significantly in comparison to the a and b ( Fig. 2 ) during these two phase transitions. The distortion index, quadratic elongation, and bond angle variance parameters...

... tetrahedra ( Liu and Lu 2006 ; Liu et al. 2008 ; Shi et al. 2013 ; Ohkubo et al. 2018 ). In the case of weakly hydrated K + ions, MD simulations and EXAFS analysis indeed revealed that the adsorbed alkali metal species residing in the interlayer surface are centered above the adjacent six-membered rings...

... and microcleavage planes (indicated by the yellow triangles in Fig. 10a ), with a flexible structure and relatively high surface energy, initiate the transformation (e.g., Min 1992 ; Lu et al. 2016 ). Meanwhile, interlayer ions K + and Si in exposed Si–O tetrahedra are readily released during alteration ( Lu et...

... anisotropic, being minimal along the [O 2 Cu 6 ] 8+ chains comprised of vertex-sharing OCu 4 tetrahedra. This peculiar thermal behavior can be explained by the anisotropy of bond-length evolution in the Cu1O 6 and Cu3O 6 octahedra and the flexibility of the S-O-Cu and Mo-O-Cu bond angles. Synthetic Zn- and V...

... reflections, is based on a loose 3D framework of alternating AsO 3 OH tetrahedra and AlO 6 octahedra. The structure is topologically equivalent to that of nafeasite and can be regarded as its Al analogue, even though nafeasite is monoclinic with space group C 2. The empirical formula (based on 2 As and 9 O...

... (29) (121), 3.640 (30) (221), 3.114 (79) (112), 2.947 (27) (400), 2.622 (27) (241) and 2.493 (27) (312). Plumbogaidonnayite has a similar spiral chain framework structure with gaidonnayite and georgechaoite, which is composed of SiO 4 tetrahedra and ZrO 6 octahedra, but with disordered extra-framework...

...) . The crystal structure was refined to R = 8.43%, wR 2 = 23.50% using single-crystal X-ray diffraction data (1578 reflections with F o > 4σ F o ). Kodamaite has a strongly layered crystal structure, with a motif based on single sheets of SiO 4 tetrahedra ( T ) that are composed of regular, planar, six...

... O pfu . In the hanahanite structure, ZnO 4 tetrahedra in adjacent sheets are linked by sharing corners and the interlayer region only contains an H 2 O group. § Corresponding author e-mail address : [email protected] 17 4 2023 26 6 2023 2023 haywoodite hanahanite new...

... the Jordan locality. It represents a framework built up of corner- and edge-sharing [ M O 6 ] octahedra, and [PO 4 ] tetrahedra ( Fig. 4 ). There are two kinds of channels that penetrate the structure along the a - and b -axes. The channels are filled with alkali-earth and alkali cations [the eightfold...

... is connected with the ν 1 (VO 4 ) 3– vibration. As has been shown for the pyromorphite–vanadinite series, even for a low content, when V 5+ substitutes for P 5+ at the tetrahedra, bands from the stretching vibration of V–O in ν 1 (VO 4 ) 3– are clearly visible in the Raman spectra (Solecka et al. , 2018...

... and was refined to an R 1 of 0.0323 for all 2594 (474 unique) reflections. The structure comprises a non-centrosymmetric arrangement of [GeS 4 ] 4− tetrahedra, forming two interstice sites: fully occupied Pb1 and partially occupied Ag1, aligned in the directions of a-, b -, and c -axes. Ruizhongite was named...

... composed of layers formed by M 1O 12 and M 2O 10 polyhedra separated by T O 4 tetrahedra perpendicular to the c axis. The abundance of distinct ions, which may be hosted at the M and T sites ( M = K, Na, Ca, Sr, Ba, Sr, Pb, Rb, Zn, Tl, Cs, Bi, NH 4 and REE; T = Si, P, V, As, S, Se, Mo, Cr and W) implies...

... ] layer, consisting of corner-sharing M O 6 octahedra and T O 4 tetrahedra ( Nikolova & Kostov-Kytin 2013 ) and having fully occupied M and T sites. However, the arrangements of the T O 4 tetrahedra in the 2 [ M ( T O 4 ) 2 ] layer differ between palmierite- and aphthitalite-type structures...