The structure and optical activity of the paraelectric phase of dicalcium strontium propionate

Glazer, A. M.; Stadnicka, Katarzyna; Singh, Sindhu

doi:10.1088/0022-3719/14/33/011

Cited by 24 publications

(9 citation statements)

References 23 publications

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“…We note that the ellipsoid for Ca is a disc flattened perpendicular to [111], whereas for Ba it is a sphere. The same shapes are found in DBP and were explained by Glazer, Stadnicka & Singh (1981) by superposition of opposite chiral structures, as a result of supposing DBP to consist of chiral microdomains.…”

Section: ( a ) Experimentalsupporting

confidence: 68%

“…The disorder was interpreted in terms of approximately two-dimensional 'platelets' of local order of opposite chiralities (in this connection note that Fd3m contains both 41 and 4 3 axes). * A structural study of the Sr salt, DSP, at room temperature (Glazer, Stadnicka & Singh, 1981) confirmed these ideas, since the structure was of a single chirality, P41212 (D~), and it was possible to use the positions of Ca and Sr to explain the anisotropic temperature factors of Ca and Ba in DBP in terms of a superposition of chiral states produced by P4t2~2e P43212® threefold rotations about cubic [111]. A low-temperature structural study by Stadnicka, Glazer, Singh & Sliwifiski (1982) enabled the spontaneous polarization of DSP in its ferroelectric phase to be calculated.…”

Section: Introductionmentioning

confidence: 99%

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Structure and disorder of dicalcium barium cyclopropanecarboxylate

Stadnicka¹,

Glazer²

1984

Acta Crystallogr Sect B

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The crystal structure of the prototype phase of dicalcium barium cyclopropanecarboxylate is described.Ca2Ba[(CH2)2CHCOO]6, Mr=728, cubic, Fd3rn (O7), a = 18.409 (9) A, V= 6239 A3, Z= 8, Dx = 1.55, Dm=l'56(l)Mgm-3;R=0"034, Rw=0.032 and Rc = 0-037 for 516 reflections. As in the isomorphous compound dicalcium barium propionate, the structure is disordered with the organic groups statistically in two sites related by a pseudomirror plane. X-ray diffuse scattering measurements show that there are correlated locally ordered regions in the form of platelets perpendicular to (100) and elongated along the (110) directions, corresponding to regions of opposite chiralities. The correlation lengths are found to be 23.4(5) A projected along [110] and 4-1 (1) projected along [001]. It has been found that at room temperature the crystal is normally orthorhombic, but that X-ray dosage stabilizes the prototype phase at this temperature. The orthorhombic-cubic transition in the absence of X-ray dosage is at about 308 K.

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Section: ( a ) Experimentalsupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Structure and disorder of dicalcium barium cyclopropanecarboxylate

Stadnicka¹,

Glazer²

1984

Acta Crystallogr Sect B

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“…lished simultaneously by Glazer, Stadnicka & Singh (1981) and Itoh, Mishima & Nakamura (1981). Although the two groups worked on crystals of opposite chiralities, both agreed that laevorotatory DSP has space group P41212(D44).…”

Section: Dicalcium Strontium Propionate (Dsp)mentioning

confidence: 99%

“…In this projection we observe both 31 and 32 axes, which alternate around the [111] direction. Kizel, Burkov, Krasilov, Kozlova, Lowry (1935) Lowry (1935) Hylleraas (1927) Hylleraas (1927) Wondre (Unpublished) Schwarzenbach (1966) Hartshorne & Stuart (1970) Glazer, Stadnicka & Singh (1981) Singh ( Both 0(2) and 0(3) atoms, each type taken on its own, form helical arrangements about the 3~ and 32 axes. However, the 0(2)-0(2) and 0(3)-0(3) distances measured about the helix axes are long (5-29 and 6.74 A), and so they cannot contribute significantly, at least in first order.…”

Section: Bi12sio2o (Bso) and Bi12geo2o (Bgo)mentioning

confidence: 99%

On the origin of optical activity in crystal structures

Glazer¹,

Stadnicka²

1986

J Appl Cryst

143

129

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Close examination of published measurements of absolute configuration in inorganic crystals has revealed many mistakes, and only a small number of published correlations between optical rotation and chirality of crystal structure can be trusted. The sense of rotation of light is here traced to the hand of specific helices of atoms, provided that the latter are correctly chosen. Four principles are given for choosing the helices. The crystals described are: low-quartz, ~-A1PO4, ct-HgS, Ca2Sr(CzHsCOO)6, BitzSiO2o, NaC103, NaBrO 3 and ~-LiIO 3. The principles suggest that the published absolute configuration of ~t-LiIO3 must be incorrect {subsequently

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“…Thus it is possible to have ferrogyrotropic S-twins. Dicalcium strontium propionate (DSP) is an example of this (Wadhawan, 1979;Glazer, Stadnicka & Singh, 1981).…”

Section: N-twinsmentioning

confidence: 99%

A Tensor Classification of Twinning in Crystals

Wadhawan¹

1997

Acta Cryst Sect A

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A classification scheme for twinning in crystals is proposed. It is based on a tensor distinction of properties across the twin interface. The classification employs concepts from the theory of transformation twinning. The adequacy of such a scheme for other main types of twins, namely growth twins and nonferroelastic mechanical twins, is examined, and found to be satisfactory. All twins can be divided into four fundamentally distinct categories: ferroelastic or S-twins, nonferroelastic-ferroic or N-twins, Bollmann or B-twins and translation or T-twins. A comparison is made of the attributes of these four types of twins. A compact and informative twin symbol is introduced, which carries information about the tensor properties in which the twins differ. Information about any underlying total or partial coincidence sublattice is incorporated by attaching a subscript t or p to the main twin symbol. Several examples are discussed. This paper also introduces a rigorous definition of prototype symmetry in terms of the 'nondisruption condition'.

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The structure and optical activity of the paraelectric phase of dicalcium strontium propionate

Cited by 24 publications

References 23 publications

Structure and disorder of dicalcium barium cyclopropanecarboxylate

Structure and disorder of dicalcium barium cyclopropanecarboxylate

On the origin of optical activity in crystal structures

A Tensor Classification of Twinning in Crystals

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