Crystal structure and thermal behavior of Cs{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]3H{sub 2}O

Journal Article · Mon Mar 01 04:00:00 EST 1999 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1998.8104· OSTI ID:338452

Touboul, M; Penin, N ^[1]; Nowogrocki, G ^[2]

---

1. UPRES, Amiens (France). Lab. de Reactivite et de Chimie des Solides
2. ENSC Lille, Villeneuve d`Ascq (France). Lab. de Cristallochimie et Physicochimie du Solide

The crystal structure of synthetic Cs{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]3H{sub 2}O was determined from single-crystal X-ray diffraction data. The compound is monoclinic, space group P2{sub 1}/c; the unit cell parameters are a = 8.424(2) {angstrom}, b = 11.378(3) {angstrom}, c = 13.160(5) {angstrom}, {beta} = 92.06(3){degree}; Z = 4. The crystal structure was solved from 6355 reflections until R = 0.029; it contains isolated [B{sub 4}O{sub 5}(OH){sub 4}]{sup 2{minus}} polyanions separated by free water molecules and Cs{sup +} ions. Although its formula is the same as that of the tincalconite Na{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]3H{sub 2}O, Cs{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]3H{sub 2}O structure is close to that of synthetic K{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]2H{sub 2}O which contains only two isolated water molecules. In the cesium and the potassium borates, the [B{sub 4}O{sub 5}(OH){sub 4}]{sup 2{minus}} anions have not a two-fold axis as in the tincalconite; the shorthand notations of these two kinds of anions shall be noted as: 4: 2{Delta} + 2T in the first two borates and 4:({Delta} + T){sub 2} in the tincalconite, {Delta} and T being triangular and tetrahedral borons, respectively. Cs{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]3H{sub 2}O indexed X-ray powder diffraction pattern is given. The dehydration of this borate occurs in two close steps and leads to an amorphous phase; this process is well explained considering the structure and especially the change in the Cs{sup +} coordination during the heating.

• OSTI ID: 338452
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 143; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
BORATES
CESIUM COMPOUNDS
CRYSTAL STRUCTURE
DEHYDRATION
EXPERIMENTAL DATA
LATTICE PARAMETERS
SYNTHESIS
THERMAL ANALYSIS
X-RAY DIFFRACTION