Lithium potassium borate and lithium rubidium borate: new non-linear optical crystals

Abstract

The title compounds, LiKB(4)O(7) and LiRbB(4)O(7), are newly developed non-linear optical crystals containing two kinds of anionic groups, namely (B(3)O(8))(7-) and (B(5)O(10))(5-). The (B(3)O(8))(7-) groups form infinite spiral chains parallel to the [100] direction, which are interconnected by sharing O atoms with (B(5)O(10))(5-) groups.

X-ray and thermoluminescence of LiKB4O7 single crystals

“…[4], the LKBO lattice is formed by two types of the boron-oxygen complexes Owing to strong covalent bond B-O inside the boron-oxygen complexes, these complexes by common, the so called bridging, oxygen atoms form the spatial frame of the LKBO single crystal (hardness 5 by Moos). Li + and K + ions are positioned in hollows formed by these boron-oxygen complexes, and are the charge compensators.…”

“…Among such newly synthesized anhydrous borates, one can name a chemical compound LiKB 4 O 7 (LKBO), which corresponds to the point of 50 mol% on the state diagram of the Li 2 B 4 O 7 -K 2 B 4 O 7 system and belongs to the space group P2 1 2 1 2 1 [4]. A very small number of physical properties for LKBO have been studied till today [8][9][10], except the single crystals growth process [5][6][7].…”

Growth and properties of new nonlinear LiKB4O7 single crystals

“…The authors of publications [7,8] ascertained that under substitution of a half of Li by K, in system Li 2 B 4 O 7 -K 2 B 4 O 7 there appears a new chemical compound LiKB 4 O 7 , which belongs to the space group P2 1 2 1 2 1 [5] and melts congruently at temperature T melt E 680 1C [8]. This means that for compounds Li 2Àx K x B 4 O 7 up to concentrations o4% weight K we deal with a case when the impurity atoms K simply dissolve in the Li 2 B 4 O 7 crystal lattice, i.e.…”

Low‐temperature change of lattice parameters in LiKB4O7 single crystals

“…In connection with this, let us consider the peculiarities of the LKB4 crystal structure. The lattice of the LKB4 crystal consists of anionic boron-oxygen groups with strong B-O covalent bonds [1]. The Li + and K + ions are found in the channel of the boronoxygen framework of the LKB4 structure and it is necessary mainly for charge compensation.…”

“…1 Introduction LiKB 4 O 7 (LKB4) is a nonlinear optical crystal, which belongs to the acentric P2 1 2 1 2 1 space group (the 222 point group) and melts congruently at temperatures T > 953 K [1,2]. Therefore, optically transparent single crystals may be grown from the stoichiometric melting composition [3,4].…”