Calcium orthophosphates, Ca

Phosphates are found in soft organic tissues as phosphate esters, and in hard tissues, notably bones and teeth, as solid calcium orthophosphates see Biomineralization). Hard tissues are composites of Apatite and an organic matrix collagen in bone, dentin, and dental cement, and keratin in dental enamel. The Apatite phases are defective with Ca/P ratios of 1.6-1.8 and can incorporate other cations (Na+, K+, Mg +) or anions (F , d , COs ", citrate). 

The build-up of Ca(0H>2 or Mg(OH)2 at the anolyte interface of the membrane-brine system can be prevented by addition of certain sequestering-gelling agents into the brine such as phosphoric acid or phosphate salts (43). A strongly hydrogen bonded non-stoichiometric calcium orthophosphate gel is formed at pH s greater than 5 to sequester the divalent ions at the membrane-brine interface, but the gel dissolves at pHs of 2-3.5. 

Water is removed by vacuum distillation and the resultant solid is separated from the purified polyether by filtration under pressure (0.4-0.6 MPa), at 80-100 °C. Similar results are obtained with calcium acid orthophosphate (Ca(H2P04)2) [97]. 

Talmage (T4) has determined the concentrations of calcium and phosphate in rat plasma after high-speed centrifugation. He has studied normal plasma and plasma to which calcium, phosphate and calcium orthophosphate had been added as well as plasma obtained after nephrectomy. There was a substantial variation in the final [Ca] [P] products (82-120) high products were obtained when the plasma phosphate concentration was high, as after nephrectomy. However, when his data are recalculated as [Ca] [P] as shown in Table 8, there is much less varia-... 

Durapattte. Hydroxylapatite calcium phosphate hydroxide calcium orthophosphate, basic hydroxyapatite Alveograf Ossopan Periograf. 3Ca3(P04)a.Ca(0H)2 Or... 

Calcium silicate-phosphates can be prepared by the following procedure. Monocalcium orthophosphate, Ca(H2P04)2, is, according to the method of Hill and Hendricks (38), recrystallized from a 50% solution of orthophosphoric acid. The crystals are then washed with acetone to remove orthophosphoric acid and dried at 70°C. By melting the resulting pure monocalcium orthophosphate at 980-1000°C., calcium metaphosphate is produced. A mixture of the calcium metaphosphate and an appropriate amount of silica gel is melted in a platinum crucible and cooled to form a glass, which has a Ca0/P205 ratio of... 

Monobasic calcium phosphate, Ca(H2P04)2, is also known as calcium hypophosphite, calcium biphosphate, acid calcium phosphate, monocalcium orthophosphate, and primary calcium phosphate. It usually exists in the form of the hydrate Ca(H2P04)2-H20. It decomposes when heated to 2oo°C (400°F)... 

Zirconyl pyrophosphate, (ZrO)2P207, mp = 2070°C, p = 3.88 g/cc, is stable up to about 1600 C, and calcium orthophosphate, Ca3(P04)2 which melts at 1820°C, can be used for some purposes at temperatures up to 1600°C. The zirconyl compound, which loses P2O5 above 1600°C, has potential use as a low-expansion ceramic, although its strength is rather limited [3]. Up to llOO C the net expansion is <1.7 x 10 C (Table 12.27). Zirconyl pyrophosphate is a good electrical insulator and its dielectric constant is similar to that of alumina [4]. Solid solutions of composition Ca Sr,. Zr4(P04)g and Zr 2-Nx i show almost zero thermal expansion over a considerable temperature range, and are promising materials for future application (see below). 

We have conducted two human metabolic studies (5,6) to compare the effects of increasing phosphorus intake on calcium utilization in healthy young adults maintained at low (ca. 400 mg/day) and high (ca. 1200 mg/day) levels of calcium intake. Increasing dietary phosphorus, as orthophosphate, caused a slight reduction in fecal calcium and a substantial reduction in urinary calcium losses (Table III). 

This class of enzymes [EC 3.6.1.38] includes calcium pumps that catalyze hydrolysis of ATP, producing ADP and orthophosphate this hydrolysis is coupled to the transport of Ca ions. 

MW 234.06 readily forms monohydrate, Ca(H2P04)2 H2O Synonyms monocalcium orthophosphate calcium biphosphate primary calcium phospate, calcium dihydrogen phosphate. 

Elemental composition Ca 38.76%, P 19.97%, 0 41.26%. Calcium may he analyzed by AA, and ICP, or x-ray methods (see Calcium). The orthophosphate anion may be analyzed by colorimetry (see Phosphorus). For colorimetric analysis the insoluble tribasic phosphate must be brought into aqueous phase hy dissolving in dilute sulfuric acid. 

CO Carbon monoxide, 2 81 CO(N3)j Carbonyl azide, 4 35 C3N3C13 Cyanuric chloride, 2 94 [C H4(OH)CH=NCH2]2 N,N -Di-salicylalethylenediamine, 3 198 CaCOa Marble, 2 49 CaP2 Calcium fluoride, 4 137 Ca(H2P04)2-H20 Calcium dihydrogen orthophosphate 1-hydrate, 4 18... 

Phosphatase Hydrolysis of phosphate Translocation of ATPases linked to cation Inorganic pyrophosphatase (pyrophosphate orthophosphate -1- PO ) Glucose-6-phosphatase Fnictose-l,6-bisphosphatase Alkaline phosphatase Phosphoprotein phosphatase (Na-, K- )-ATPase (Mg +, Ca +)-ATPase Proton-translocating ATPase Zn Zii Sodium pump Calcium pump pump... 

The interest in mineral fortification of milk for the production of milks with higher nutritional value is a challenge. This is because the introduction of minerals upsets the mineral-protein equilibria in milk which will affect their stability. Philippe et al. (2004) showed that supplementation of skim milk with calcium gluconate, calcium lactate, or calcium chloride (up to 16 mmole added Ca/kg) decreased the heat stability. The addition of MgCl2 or FeCla (at a level of 8 mmole/kg) also reduced the heat stability of casein micelles (Philippe et al., 2005). However, by manipulating the mineral equilibria of milk with the use of a combination of soluble calcium salts and orthophosphates, it is possible to produce milks (with up to 20 mmole added Ca/kg) that are stable to heating (Williams et al., 2005). O Kennedy et al. (2001) showed that denatured whey proteins could be used as a carrier for calcium phosphate and further that adequate heat stability at 130 °C of whey protein-calcium phosphate suspensions could be achieved by appropriate adjustment of pH. 

CaC03 Marble, 2 49 CaF2 Calcium fluoride, 4 137 Ca(H2P04)2-H20 Calcium dihydrogen orthophosphate 1-hydrate, 4 18... 

Calcium Phosphate Monobasic. Acid calcium phosphate calcium biphosphate monocalcium orthophosphate monocalcium phosphate primary calcium phosphate "calcium superphosphate". CaH4OtP] mol wt 234.06. Ca 17.12%, H 1-72%, O 54.69%, P 26.47%. CaiHjPO ), Commercial prepn for fertilizers by treating pulverized phosphate rock with HjSO. or H2POt Faith, Keyes St Clark s Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds, (Wiley-Interscience, New York, 4th ed., 1975) pp 191-200. Laboratory prepn from CaCO, and H,P04 Jensen, Kath-ley, lnorg. Syn. 4, 18 (1953). 

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