Crystal structure of tetragonal

O Connor, B. H., and Dale, D. H. (1966). A neutron diffraction analysis of the crystal structure of tetragonal nickel sulfate hexadeuterate. Acta Crystallogr. 21, 705-709. 

FIG. 12.14. The crystal structure of tetragonal PbO (and SnO). The small shaded circles represent metal atoms. The arrangement of bonds from a metal atom is shown at the right, where the two dots represent the inert pair of electrons (see p. 937). 

Mijihoff, F. C., The crystal structure of tetragonal selenium trioxide, Acta Crystallogr., Sect. B Struct. Sci., 18, (1965), 795-798. Cited on page 127. 

Although correlation between parameters is a function of the data structure and has nothing to do with deficiencies in the model, it has implications for both the choice of the model and the design of the experiment. EVANS described his experiences with the determination of the crystal structure of tetragonal barium titanate (BaTiOa). The problem was ample in that it involved only three atomic positional parameters (one for Ti and two for 0), plus nine thermal parameters. There was considerable interest in the details of the structure because of the ferroelectric properties of the material. The proposed model was essentially a simple cubic arrangement of atoms, but with Ti displaced slightly from the center of an octahedron. By ordinary x-ray standards, this distortion (which was expected to be on the order of 0.15 A) could be measured with a standard error of 0.01-0.02 A if... 

G. Teufer, The crystal structure of tetragonal Zr02, Acta Crystallogr. 15, 1187 (1962). 

Figure 8.17 Crystal structure of tetragonal CaC2 showing the resemblance to NaCl (p. 242). Above 450°C the parallel alignment of the C2 units breaks down and the structure becomes cubic.

Figure 10.1 Crystal structures of tetragonal La2Cu04, Nd2Cu04, YBa2Cu307 and...

Figure 10.8 Crystal structure of tetragonal infinite layer form of MQ1O2.

Figure 9. Crystal structure of tetragonal a-MoB (space group Idi/amd).

Figure 21. Crystal structures of tetragonal MoSi2, hexagonal CrSi2, and orthorhombic TiSi2. The CN 10 polyhedra of silicon atoms around the transition metal atoms and parts of the two-dimensionally close packed TSi2 layers are outlined for each structure.

Figure 9.6 (a) Crystal structure of tetragonal YBa2Cu306. Space group P4/mmm, (b) Crystal... 

Figure E.3 Crystal structure of tetragonal HgBa2Cu04+s. The symmetry may be reduced compared to space group /4/mmm a = 0.3880nm, c = 0.951 nm. The extra Os" oxygen ions may actually occupy an eightfold split position.

Figure 1.5 Crystal structure of tetragonal zirconia and relation between tetragonal (t) cell and pseudo-cubic fluorite (F) ceU. The closed and shaded open circles denote the cations and anions, respectively. An arrow in an open circle indicates the displacement of oxygen atoms along the c axis. The thick blue dashed lines indicate a primitive tetragonal cell and thin solid lines stand for two pseudo-fluorite cells. ...

Phase identification and crystal Structure of tetragonal phase in the compositionally homogeneous Ce, rj j02 - t, t, and t" forms... 

Figure 6.4 Crystal structure of ar-tetragonal boron. This was originally thought to be B50 (4Bi2 + 2B) but is now known to be either B50C2 or B50N2 in which the 2C (or 2N) occupy the 2(b) positions the remaining 2B are distributed statistically at other vacant sites in the lattice. Note that this reformulation solves three problems which attended the description of the or-tetragonal phase as a crystalline modification of pure B ...

Three forms of titanium dioxide, Ti02, are known. Of these the crystal structures of the two tetragonal forms, rutile and anatase, have been thoroughly investigated2) in each case only one parameter is involved, and the atomic arrangement has been accurately determined. The third form, brookite, is orthorhombic, with axial ratios... 

Transannular interaction via the electron-delocalization mechanism was found, but lessened by 10-15% for the ligand superhyperfine splitting and 30-35% for the hyperfine splitting (62) in the epr spectrum. The crystal structure of [VOS2CNEt2)2] shows that the molecular core has the expected C2V symmetry [V-0 = 159.1(4), V-S = 138.7(2)-241.0(2) pm] (63). Magnetic and spectral data provided evidence for a tetragonal, pyramidal structure (VII) for these complexes. Like many other coordinatively unsaturated, metal... 

In the crystal structure of these phases with tetragonal symmetry (P4/mbm, D h) the boron covalent sublattice is formed by chains of octahedra, developing along the c axis and by pairs of B atoms, bonding the octahedra in the xOy plane (see Fig. 1). The resulting three-dimensional skeleton contains tunnels parallel to the c axis that are filled by metal atoms . ... 

Boron is as unusual in its structures as it is in its chemical behavior. Sixteen boron modifications have been described, but most of them have not been well characterized. Many samples assumed to have consisted only of boron were possibly boron-rich borides (many of which are known, e.g. YB66). An established structure is that of rhombohedral a-B12 (the subscript number designates the number of atoms per unit cell). The crystal structures of three further forms are known, tetragonal -B50, rhombohedral J3-B105 and rhombohedral j3-B 320, but probably boron-rich borides were studied. a-B50 should be formulated B48X2. It consists of B12 icosahedra that are linked by tetrahedrally coordinated X atoms. These atoms are presumably C or N atoms (B, C and N can hardly be distinguished by X-ray diffraction). 

There are three crystal structures of titanium dioxide rutile, anatase, and brookite. The most active phase is rutile, which has a tetragonal structure [133], as shown in Figure 8.5 [134],... 

Table 2.1 shows the crystal structure data of the phases existing in the Mg-H system. Pnre Mg has a hexagonal crystal structure and its hydride has a tetragonal lattice nnit cell (rutile type). The low-pressure MgH is commonly designated as P-MgH in order to differentiate it from its high-pressure polymorph, which will be discussed later. Figure 2.2 shows the crystal structure of p-MgH where the positions of Mg and H atoms are clearly discerned. Precise measurements of the lattice parameters of p-MgH by synchrotron X-ray diffraction yielded a = 0.45180(6) mn and c = 0.30211(4) nm [2]. The powder diffraction file JCPDS 12-0697 lists a = 0.4517 nm and c = 0.30205 nm. The density of MgH is 1.45 g/cm [3]. 

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